diff --git a/.github/.OwlBot.lock.yaml b/.github/.OwlBot.lock.yaml
new file mode 100644
index 0000000000..cd8bc8740c
--- /dev/null
+++ b/.github/.OwlBot.lock.yaml
@@ -0,0 +1,9 @@
+# Copyright 2021 Google LLC
+#
+# Use of this source code is governed by a BSD-style
+# license that can be found in the LICENSE file or at
+# https://developers.google.com/open-source/licenses/bsd
+
+docker:
+  image: gcr.io/repo-automation-bots/owlbot-python:latest
+  digest: sha256:0ffe3bdd6c7159692df5f7744da74e5ef19966288a6bf76023e8e04e0c424d7d
diff --git a/.github/.OwlBot.yaml b/.github/.OwlBot.yaml
new file mode 100644
index 0000000000..1bfc664928
--- /dev/null
+++ b/.github/.OwlBot.yaml
@@ -0,0 +1,8 @@
+# Copyright 2021 Google LLC
+#
+# Use of this source code is governed by a BSD-style
+# license that can be found in the LICENSE file or at
+# https://developers.google.com/open-source/licenses/bsd
+
+docker:
+  image: gcr.io/repo-automation-bots/owlbot-python:latest
diff --git a/.github/workflows/django_tests_against_emulator0.yml b/.github/workflows/django_tests_against_emulator0.yml
index 0f7f7c99db..2b31049e72 100644
--- a/.github/workflows/django_tests_against_emulator0.yml
+++ b/.github/workflows/django_tests_against_emulator0.yml
@@ -1,7 +1,7 @@
 on:
   push:
     branches:
-      - master
+      - main
   pull_request:
 name: django-tests0
 jobs:
diff --git a/.github/workflows/django_tests_against_emulator1.yml b/.github/workflows/django_tests_against_emulator1.yml
index 921a9a5848..722a593af1 100644
--- a/.github/workflows/django_tests_against_emulator1.yml
+++ b/.github/workflows/django_tests_against_emulator1.yml
@@ -1,7 +1,7 @@
 on:
   push:
     branches:
-      - master
+      - main
   pull_request:
 name: django-tests1
 jobs:
diff --git a/.github/workflows/django_tests_against_emulator2.yml b/.github/workflows/django_tests_against_emulator2.yml
index 682de38ed6..364803ab3a 100644
--- a/.github/workflows/django_tests_against_emulator2.yml
+++ b/.github/workflows/django_tests_against_emulator2.yml
@@ -1,7 +1,7 @@
 on:
   push:
     branches:
-      - master
+      - main
   pull_request:
 name: django-tests2
 jobs:
diff --git a/.github/workflows/django_tests_against_emulator3.yml b/.github/workflows/django_tests_against_emulator3.yml
index ea83185a82..9e2df8ae94 100644
--- a/.github/workflows/django_tests_against_emulator3.yml
+++ b/.github/workflows/django_tests_against_emulator3.yml
@@ -1,7 +1,7 @@
 on:
   push:
     branches:
-      - master
+      - main
   pull_request:
 name: django-tests3
 jobs:
diff --git a/.github/workflows/django_tests_against_emulator4.yml b/.github/workflows/django_tests_against_emulator4.yml
index 6a59ff7725..361dccfbc7 100644
--- a/.github/workflows/django_tests_against_emulator4.yml
+++ b/.github/workflows/django_tests_against_emulator4.yml
@@ -1,7 +1,7 @@
 on:
   push:
     branches:
-      - master
+      - main
   pull_request:
 name: django-tests4
 jobs:
diff --git a/.github/workflows/django_tests_against_emulator5.yml b/.github/workflows/django_tests_against_emulator5.yml
index f07609fb2f..817b0c4295 100644
--- a/.github/workflows/django_tests_against_emulator5.yml
+++ b/.github/workflows/django_tests_against_emulator5.yml
@@ -1,7 +1,7 @@
 on:
   push:
     branches:
-      - master
+      - main
   pull_request:
 name: django-tests5
 jobs:
diff --git a/.github/workflows/django_tests_against_emulator6.yml b/.github/workflows/django_tests_against_emulator6.yml
index 3984852de2..ab9d817c98 100644
--- a/.github/workflows/django_tests_against_emulator6.yml
+++ b/.github/workflows/django_tests_against_emulator6.yml
@@ -1,7 +1,7 @@
 on:
   push:
     branches:
-      - master
+      - main
   pull_request:
 name: django-tests6
 jobs:
diff --git a/.github/workflows/django_tests_against_emulator7.yml b/.github/workflows/django_tests_against_emulator7.yml
index 0932197f86..4ee19f9373 100644
--- a/.github/workflows/django_tests_against_emulator7.yml
+++ b/.github/workflows/django_tests_against_emulator7.yml
@@ -1,7 +1,7 @@
 on:
   push:
     branches:
-      - master
+      - main
   pull_request:
 name: django-tests7
 jobs:
diff --git a/.github/workflows/django_tests_against_emulator8.yml b/.github/workflows/django_tests_against_emulator8.yml
index 98d4b5f1d8..5c148ddd23 100644
--- a/.github/workflows/django_tests_against_emulator8.yml
+++ b/.github/workflows/django_tests_against_emulator8.yml
@@ -1,7 +1,7 @@
 on:
   push:
     branches:
-      - master
+      - main
   pull_request:
 name: django-tests8
 jobs:
diff --git a/.github/workflows/django_tests_against_emulator9.yml b/.github/workflows/django_tests_against_emulator9.yml
index 0ba4baefce..4388c3cfa6 100644
--- a/.github/workflows/django_tests_against_emulator9.yml
+++ b/.github/workflows/django_tests_against_emulator9.yml
@@ -1,7 +1,7 @@
 on:
   push:
     branches:
-      - master
+      - main
   pull_request:
 name: django-tests9
 jobs:
diff --git a/.github/workflows/integration-tests-against-emulator.yml b/.github/workflows/integration-tests-against-emulator.yml
index efd2c4e5bb..5767e966bb 100644
--- a/.github/workflows/integration-tests-against-emulator.yml
+++ b/.github/workflows/integration-tests-against-emulator.yml
@@ -1,7 +1,7 @@
 on:
   push:
     branches:
-      - master
+      - main
   pull_request:
 name: Run Django Spanner integration tests against emulator
 jobs:
diff --git a/.kokoro/build.sh b/.kokoro/build.sh
index 4ac9dd8b76..eea1d84933 100755
--- a/.kokoro/build.sh
+++ b/.kokoro/build.sh
@@ -1,17 +1,9 @@
 #!/bin/bash
 # Copyright 2020 Google LLC
 #
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#     https://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
+# Use of this source code is governed by a BSD-style
+# license that can be found in the LICENSE file or at
+# https://developers.google.com/open-source/licenses/bsd
 
 set -eo pipefail
 
diff --git a/.kokoro/docker/docs/Dockerfile b/.kokoro/docker/docs/Dockerfile
index 412b0b56a9..92ade8f99f 100644
--- a/.kokoro/docker/docs/Dockerfile
+++ b/.kokoro/docker/docs/Dockerfile
@@ -1,16 +1,8 @@
 # Copyright 2020 Google LLC
 #
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#     http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
+# Use of this source code is governed by a BSD-style
+# license that can be found in the LICENSE file or at
+# https://developers.google.com/open-source/licenses/bsd
 
 from ubuntu:20.04
 
@@ -40,6 +32,7 @@ RUN apt-get update \
     libssl-dev \
     libsqlite3-dev \
     portaudio19-dev \
+    python3-distutils \
     redis-server \
     software-properties-common \
     ssh \
@@ -59,40 +52,8 @@ RUN apt-get update \
   && rm -rf /var/lib/apt/lists/* \
   && rm -f /var/cache/apt/archives/*.deb
 
-
-COPY fetch_gpg_keys.sh /tmp
-# Install the desired versions of Python.
-RUN set -ex \
-    && export GNUPGHOME="$(mktemp -d)" \
-    && echo "disable-ipv6" >> "${GNUPGHOME}/dirmngr.conf" \
-    && /tmp/fetch_gpg_keys.sh \
-    && for PYTHON_VERSION in 3.7.8 3.8.5; do \
-        wget --no-check-certificate -O python-${PYTHON_VERSION}.tar.xz "https://www.python.org/ftp/python/${PYTHON_VERSION%%[a-z]*}/Python-$PYTHON_VERSION.tar.xz" \
-        && wget --no-check-certificate -O python-${PYTHON_VERSION}.tar.xz.asc "https://www.python.org/ftp/python/${PYTHON_VERSION%%[a-z]*}/Python-$PYTHON_VERSION.tar.xz.asc" \
-        && gpg --batch --verify python-${PYTHON_VERSION}.tar.xz.asc python-${PYTHON_VERSION}.tar.xz \
-        && rm -r python-${PYTHON_VERSION}.tar.xz.asc \
-        && mkdir -p /usr/src/python-${PYTHON_VERSION} \
-        && tar -xJC /usr/src/python-${PYTHON_VERSION} --strip-components=1 -f python-${PYTHON_VERSION}.tar.xz \
-        && rm python-${PYTHON_VERSION}.tar.xz \
-        && cd /usr/src/python-${PYTHON_VERSION} \
-        && ./configure \
-            --enable-shared \
-            # This works only on Python 2.7 and throws a warning on every other
-            # version, but seems otherwise harmless.
-            --enable-unicode=ucs4 \
-            --with-system-ffi \
-            --without-ensurepip \
-        && make -j$(nproc) \
-        && make install \
-        && ldconfig \
-  ; done \
-  && rm -rf "${GNUPGHOME}" \
-  && rm -rf /usr/src/python* \
-  && rm -rf ~/.cache/
-
 RUN wget -O /tmp/get-pip.py 'https://bootstrap.pypa.io/get-pip.py' \
-  && python3.7 /tmp/get-pip.py \
   && python3.8 /tmp/get-pip.py \
   && rm /tmp/get-pip.py
 
-CMD ["python3.7"]
+CMD ["python3.8"]
diff --git a/.kokoro/docker/docs/fetch_gpg_keys.sh b/.kokoro/docker/docs/fetch_gpg_keys.sh
index d653dd868e..c26695ddf0 100755
--- a/.kokoro/docker/docs/fetch_gpg_keys.sh
+++ b/.kokoro/docker/docs/fetch_gpg_keys.sh
@@ -1,21 +1,13 @@
 #!/bin/bash
 # Copyright 2020 Google LLC
 #
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#      http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
+# Use of this source code is governed by a BSD-style
+# license that can be found in the LICENSE file or at
+# https://developers.google.com/open-source/licenses/bsd
 
 # A script to fetch gpg keys with retry.
 # Avoid jinja parsing the file.
-# 
+#
 
 function retry {
     if [[ "${#}" -le 1 ]]; then
@@ -42,4 +34,4 @@ retry 3 gpg --keyserver ha.pool.sks-keyservers.net --recv-keys \
 retry 3 gpg --keyserver ha.pool.sks-keyservers.net --recv-keys \
       E3FF2839C048B25C084DEBE9B26995E310250568
 
-# 
+#
diff --git a/.kokoro/docs/common.cfg b/.kokoro/docs/common.cfg
index 2003193838..cdf8e2a4ef 100644
--- a/.kokoro/docs/common.cfg
+++ b/.kokoro/docs/common.cfg
@@ -62,4 +62,4 @@ before_action {
       keyname: "docuploader_service_account"
     }
   }
-}
+}
\ No newline at end of file
diff --git a/.kokoro/populate-secrets.sh b/.kokoro/populate-secrets.sh
new file mode 100755
index 0000000000..7b511c3257
--- /dev/null
+++ b/.kokoro/populate-secrets.sh
@@ -0,0 +1,35 @@
+#!/bin/bash
+# Copyright 2020 Google LLC
+#
+# Use of this source code is governed by a BSD-style
+# license that can be found in the LICENSE file or at
+# https://developers.google.com/open-source/licenses/bsd
+
+set -eo pipefail
+
+function now { date +"%Y-%m-%d %H:%M:%S" | tr -d '\n' ;}
+function msg { println "$*" >&2 ;}
+function println { printf '%s\n' "$(now) $*" ;}
+
+
+# Populates requested secrets set in SECRET_MANAGER_KEYS from service account:
+# kokoro-trampoline@cloud-devrel-kokoro-resources.iam.gserviceaccount.com
+SECRET_LOCATION="${KOKORO_GFILE_DIR}/secret_manager"
+msg "Creating folder on disk for secrets: ${SECRET_LOCATION}"
+mkdir -p ${SECRET_LOCATION}
+for key in $(echo ${SECRET_MANAGER_KEYS} | sed "s/,/ /g")
+do
+  msg "Retrieving secret ${key}"
+  docker run --entrypoint=gcloud \
+    --volume=${KOKORO_GFILE_DIR}:${KOKORO_GFILE_DIR} \
+    gcr.io/google.com/cloudsdktool/cloud-sdk \
+    secrets versions access latest \
+    --project cloud-devrel-kokoro-resources \
+    --secret ${key} > \
+    "${SECRET_LOCATION}/${key}"
+  if [[ $? == 0 ]]; then
+    msg "Secret written to ${SECRET_LOCATION}/${key}"
+  else
+    msg "Error retrieving secret ${key}"
+  fi
+done
diff --git a/.kokoro/publish-docs.sh b/.kokoro/publish-docs.sh
index 8acb14e802..a80ea7c0a0 100755
--- a/.kokoro/publish-docs.sh
+++ b/.kokoro/publish-docs.sh
@@ -1,17 +1,9 @@
 #!/bin/bash
 # Copyright 2020 Google LLC
 #
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#     https://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
+# Use of this source code is governed by a BSD-style
+# license that can be found in the LICENSE file or at
+# https://developers.google.com/open-source/licenses/bsd
 
 set -eo pipefail
 
diff --git a/.kokoro/release.sh b/.kokoro/release.sh
index 9f60d5f251..57e2f28ce1 100755
--- a/.kokoro/release.sh
+++ b/.kokoro/release.sh
@@ -1,19 +1,9 @@
 #!/bin/bash
 # Copyright 2020 Google LLC
 #
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#     https://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-
-#!/bin/bash
+# Use of this source code is governed by a BSD-style
+# license that can be found in the LICENSE file or at
+# https://developers.google.com/open-source/licenses/bsd
 
 set -eo pipefail
 
@@ -28,7 +18,7 @@ python3 -m pip install --upgrade twine wheel setuptools
 export PYTHONUNBUFFERED=1
 
 # Move into the package, build the distribution and upload.
-TWINE_PASSWORD=$(cat "${KOKORO_KEYSTORE_DIR}/73713_google_cloud_pypi_password")
+TWINE_PASSWORD=$(cat "${KOKORO_GFILE_DIR}/secret_manager/google-cloud-pypi-token")
 cd github/python-spanner-django
 python3 setup.py sdist bdist_wheel
-twine upload --username gcloudpypi --password "${TWINE_PASSWORD}" dist/*
+twine upload --username __token__ --password "${TWINE_PASSWORD}" dist/*
diff --git a/.kokoro/release/common.cfg b/.kokoro/release/common.cfg
index 31533b977a..2cf743579d 100644
--- a/.kokoro/release/common.cfg
+++ b/.kokoro/release/common.cfg
@@ -23,42 +23,8 @@ env_vars: {
     value: "github/python-spanner-django/.kokoro/release.sh"
 }
 
-# Fetch the token needed for reporting release status to GitHub
-before_action {
-  fetch_keystore {
-    keystore_resource {
-      keystore_config_id: 73713
-      keyname: "yoshi-automation-github-key"
-    }
-  }
-}
-
-# Fetch PyPI password
-before_action {
-  fetch_keystore {
-    keystore_resource {
-      keystore_config_id: 73713
-      keyname: "google_cloud_pypi_password"
-    }
-  }
-}
-
-# Fetch magictoken to use with Magic Github Proxy 
-before_action {
-  fetch_keystore {
-    keystore_resource {
-      keystore_config_id: 73713
-      keyname: "releasetool-magictoken"
-    }
-  }
-}
-
-# Fetch api key to use with Magic Github Proxy 
-before_action {
-  fetch_keystore {
-    keystore_resource {
-      keystore_config_id: 73713
-      keyname: "magic-github-proxy-api-key"
-    }
-  }
+# Tokens needed to report release status back to GitHub
+env_vars: {
+  key: "SECRET_MANAGER_KEYS"
+  value: "releasetool-publish-reporter-app,releasetool-publish-reporter-googleapis-installation,releasetool-publish-reporter-pem,google-cloud-pypi-token"
 }
diff --git a/.kokoro/release/release.cfg b/.kokoro/release/release.cfg
index 18a4c35325..8f43917d92 100644
--- a/.kokoro/release/release.cfg
+++ b/.kokoro/release/release.cfg
@@ -1 +1 @@
-# Format: //devtools/kokoro/config/proto/build.proto
+# Format: //devtools/kokoro/config/proto/build.proto
\ No newline at end of file
diff --git a/.kokoro/samples/lint/common.cfg b/.kokoro/samples/lint/common.cfg
new file mode 100644
index 0000000000..b42e774271
--- /dev/null
+++ b/.kokoro/samples/lint/common.cfg
@@ -0,0 +1,34 @@
+# Format: //devtools/kokoro/config/proto/build.proto
+
+# Build logs will be here
+action {
+  define_artifacts {
+    regex: "**/*sponge_log.xml"
+  }
+}
+
+# Specify which tests to run
+env_vars: {
+    key: "RUN_TESTS_SESSION"
+    value: "lint"
+}
+
+env_vars: {
+    key: "TRAMPOLINE_BUILD_FILE"
+    value: "github/python-spanner-django/.kokoro/test-samples.sh"
+}
+
+# Configure the docker image for kokoro-trampoline.
+env_vars: {
+    key: "TRAMPOLINE_IMAGE"
+    value: "gcr.io/cloud-devrel-kokoro-resources/python-samples-testing-docker"
+}
+
+# Download secrets for samples
+gfile_resources: "/bigstore/cloud-devrel-kokoro-resources/python-docs-samples"
+
+# Download trampoline resources.
+gfile_resources: "/bigstore/cloud-devrel-kokoro-resources/trampoline"
+
+# Use the trampoline script to run in docker.
+build_file: "python-spanner-django/.kokoro/trampoline.sh"
\ No newline at end of file
diff --git a/.kokoro/samples/lint/continuous.cfg b/.kokoro/samples/lint/continuous.cfg
new file mode 100644
index 0000000000..a1c8d9759c
--- /dev/null
+++ b/.kokoro/samples/lint/continuous.cfg
@@ -0,0 +1,6 @@
+# Format: //devtools/kokoro/config/proto/build.proto
+
+env_vars: {
+    key: "INSTALL_LIBRARY_FROM_SOURCE"
+    value: "True"
+}
\ No newline at end of file
diff --git a/.kokoro/samples/lint/periodic.cfg b/.kokoro/samples/lint/periodic.cfg
new file mode 100644
index 0000000000..50fec96497
--- /dev/null
+++ b/.kokoro/samples/lint/periodic.cfg
@@ -0,0 +1,6 @@
+# Format: //devtools/kokoro/config/proto/build.proto
+
+env_vars: {
+    key: "INSTALL_LIBRARY_FROM_SOURCE"
+    value: "False"
+}
\ No newline at end of file
diff --git a/.kokoro/samples/lint/presubmit.cfg b/.kokoro/samples/lint/presubmit.cfg
new file mode 100644
index 0000000000..a1c8d9759c
--- /dev/null
+++ b/.kokoro/samples/lint/presubmit.cfg
@@ -0,0 +1,6 @@
+# Format: //devtools/kokoro/config/proto/build.proto
+
+env_vars: {
+    key: "INSTALL_LIBRARY_FROM_SOURCE"
+    value: "True"
+}
\ No newline at end of file
diff --git a/.kokoro/samples/python3.6/common.cfg b/.kokoro/samples/python3.6/common.cfg
new file mode 100644
index 0000000000..6e32d40d20
--- /dev/null
+++ b/.kokoro/samples/python3.6/common.cfg
@@ -0,0 +1,40 @@
+# Format: //devtools/kokoro/config/proto/build.proto
+
+# Build logs will be here
+action {
+  define_artifacts {
+    regex: "**/*sponge_log.xml"
+  }
+}
+
+# Specify which tests to run
+env_vars: {
+    key: "RUN_TESTS_SESSION"
+    value: "py-3.6"
+}
+
+# Declare build specific Cloud project.
+env_vars: {
+    key: "BUILD_SPECIFIC_GCLOUD_PROJECT"
+    value: "python-docs-samples-tests-py36"
+}
+
+env_vars: {
+    key: "TRAMPOLINE_BUILD_FILE"
+    value: "github/python-spanner-django/.kokoro/test-samples.sh"
+}
+
+# Configure the docker image for kokoro-trampoline.
+env_vars: {
+    key: "TRAMPOLINE_IMAGE"
+    value: "gcr.io/cloud-devrel-kokoro-resources/python-samples-testing-docker"
+}
+
+# Download secrets for samples
+gfile_resources: "/bigstore/cloud-devrel-kokoro-resources/python-docs-samples"
+
+# Download trampoline resources.
+gfile_resources: "/bigstore/cloud-devrel-kokoro-resources/trampoline"
+
+# Use the trampoline script to run in docker.
+build_file: "python-spanner-django/.kokoro/trampoline.sh"
\ No newline at end of file
diff --git a/.kokoro/samples/python3.6/continuous.cfg b/.kokoro/samples/python3.6/continuous.cfg
new file mode 100644
index 0000000000..7218af1499
--- /dev/null
+++ b/.kokoro/samples/python3.6/continuous.cfg
@@ -0,0 +1,7 @@
+# Format: //devtools/kokoro/config/proto/build.proto
+
+env_vars: {
+    key: "INSTALL_LIBRARY_FROM_SOURCE"
+    value: "True"
+}
+
diff --git a/.kokoro/samples/python3.6/periodic-head.cfg b/.kokoro/samples/python3.6/periodic-head.cfg
new file mode 100644
index 0000000000..f9cfcd33e0
--- /dev/null
+++ b/.kokoro/samples/python3.6/periodic-head.cfg
@@ -0,0 +1,11 @@
+# Format: //devtools/kokoro/config/proto/build.proto
+
+env_vars: {
+    key: "INSTALL_LIBRARY_FROM_SOURCE"
+    value: "True"
+}
+
+env_vars: {
+    key: "TRAMPOLINE_BUILD_FILE"
+    value: "github/python-pubsub/.kokoro/test-samples-against-head.sh"
+}
diff --git a/.kokoro/samples/python3.6/periodic.cfg b/.kokoro/samples/python3.6/periodic.cfg
new file mode 100644
index 0000000000..50fec96497
--- /dev/null
+++ b/.kokoro/samples/python3.6/periodic.cfg
@@ -0,0 +1,6 @@
+# Format: //devtools/kokoro/config/proto/build.proto
+
+env_vars: {
+    key: "INSTALL_LIBRARY_FROM_SOURCE"
+    value: "False"
+}
\ No newline at end of file
diff --git a/.kokoro/samples/python3.6/presubmit.cfg b/.kokoro/samples/python3.6/presubmit.cfg
new file mode 100644
index 0000000000..a1c8d9759c
--- /dev/null
+++ b/.kokoro/samples/python3.6/presubmit.cfg
@@ -0,0 +1,6 @@
+# Format: //devtools/kokoro/config/proto/build.proto
+
+env_vars: {
+    key: "INSTALL_LIBRARY_FROM_SOURCE"
+    value: "True"
+}
\ No newline at end of file
diff --git a/.kokoro/samples/python3.7/common.cfg b/.kokoro/samples/python3.7/common.cfg
new file mode 100644
index 0000000000..407c854ff0
--- /dev/null
+++ b/.kokoro/samples/python3.7/common.cfg
@@ -0,0 +1,40 @@
+# Format: //devtools/kokoro/config/proto/build.proto
+
+# Build logs will be here
+action {
+  define_artifacts {
+    regex: "**/*sponge_log.xml"
+  }
+}
+
+# Specify which tests to run
+env_vars: {
+    key: "RUN_TESTS_SESSION"
+    value: "py-3.7"
+}
+
+# Declare build specific Cloud project.
+env_vars: {
+    key: "BUILD_SPECIFIC_GCLOUD_PROJECT"
+    value: "python-docs-samples-tests-py37"
+}
+
+env_vars: {
+    key: "TRAMPOLINE_BUILD_FILE"
+    value: "github/python-spanner-django/.kokoro/test-samples.sh"
+}
+
+# Configure the docker image for kokoro-trampoline.
+env_vars: {
+    key: "TRAMPOLINE_IMAGE"
+    value: "gcr.io/cloud-devrel-kokoro-resources/python-samples-testing-docker"
+}
+
+# Download secrets for samples
+gfile_resources: "/bigstore/cloud-devrel-kokoro-resources/python-docs-samples"
+
+# Download trampoline resources.
+gfile_resources: "/bigstore/cloud-devrel-kokoro-resources/trampoline"
+
+# Use the trampoline script to run in docker.
+build_file: "python-spanner-django/.kokoro/trampoline.sh"
\ No newline at end of file
diff --git a/.kokoro/samples/python3.7/continuous.cfg b/.kokoro/samples/python3.7/continuous.cfg
new file mode 100644
index 0000000000..a1c8d9759c
--- /dev/null
+++ b/.kokoro/samples/python3.7/continuous.cfg
@@ -0,0 +1,6 @@
+# Format: //devtools/kokoro/config/proto/build.proto
+
+env_vars: {
+    key: "INSTALL_LIBRARY_FROM_SOURCE"
+    value: "True"
+}
\ No newline at end of file
diff --git a/.kokoro/samples/python3.7/periodic-head.cfg b/.kokoro/samples/python3.7/periodic-head.cfg
new file mode 100644
index 0000000000..f9cfcd33e0
--- /dev/null
+++ b/.kokoro/samples/python3.7/periodic-head.cfg
@@ -0,0 +1,11 @@
+# Format: //devtools/kokoro/config/proto/build.proto
+
+env_vars: {
+    key: "INSTALL_LIBRARY_FROM_SOURCE"
+    value: "True"
+}
+
+env_vars: {
+    key: "TRAMPOLINE_BUILD_FILE"
+    value: "github/python-pubsub/.kokoro/test-samples-against-head.sh"
+}
diff --git a/.kokoro/samples/python3.7/periodic.cfg b/.kokoro/samples/python3.7/periodic.cfg
new file mode 100644
index 0000000000..50fec96497
--- /dev/null
+++ b/.kokoro/samples/python3.7/periodic.cfg
@@ -0,0 +1,6 @@
+# Format: //devtools/kokoro/config/proto/build.proto
+
+env_vars: {
+    key: "INSTALL_LIBRARY_FROM_SOURCE"
+    value: "False"
+}
\ No newline at end of file
diff --git a/.kokoro/samples/python3.7/presubmit.cfg b/.kokoro/samples/python3.7/presubmit.cfg
new file mode 100644
index 0000000000..a1c8d9759c
--- /dev/null
+++ b/.kokoro/samples/python3.7/presubmit.cfg
@@ -0,0 +1,6 @@
+# Format: //devtools/kokoro/config/proto/build.proto
+
+env_vars: {
+    key: "INSTALL_LIBRARY_FROM_SOURCE"
+    value: "True"
+}
\ No newline at end of file
diff --git a/.kokoro/samples/python3.8/common.cfg b/.kokoro/samples/python3.8/common.cfg
new file mode 100644
index 0000000000..07b0e8fddb
--- /dev/null
+++ b/.kokoro/samples/python3.8/common.cfg
@@ -0,0 +1,40 @@
+# Format: //devtools/kokoro/config/proto/build.proto
+
+# Build logs will be here
+action {
+  define_artifacts {
+    regex: "**/*sponge_log.xml"
+  }
+}
+
+# Specify which tests to run
+env_vars: {
+    key: "RUN_TESTS_SESSION"
+    value: "py-3.8"
+}
+
+# Declare build specific Cloud project.
+env_vars: {
+    key: "BUILD_SPECIFIC_GCLOUD_PROJECT"
+    value: "python-docs-samples-tests-py38"
+}
+
+env_vars: {
+    key: "TRAMPOLINE_BUILD_FILE"
+    value: "github/python-spanner-django/.kokoro/test-samples.sh"
+}
+
+# Configure the docker image for kokoro-trampoline.
+env_vars: {
+    key: "TRAMPOLINE_IMAGE"
+    value: "gcr.io/cloud-devrel-kokoro-resources/python-samples-testing-docker"
+}
+
+# Download secrets for samples
+gfile_resources: "/bigstore/cloud-devrel-kokoro-resources/python-docs-samples"
+
+# Download trampoline resources.
+gfile_resources: "/bigstore/cloud-devrel-kokoro-resources/trampoline"
+
+# Use the trampoline script to run in docker.
+build_file: "python-spanner-django/.kokoro/trampoline.sh"
\ No newline at end of file
diff --git a/.kokoro/samples/python3.8/continuous.cfg b/.kokoro/samples/python3.8/continuous.cfg
new file mode 100644
index 0000000000..a1c8d9759c
--- /dev/null
+++ b/.kokoro/samples/python3.8/continuous.cfg
@@ -0,0 +1,6 @@
+# Format: //devtools/kokoro/config/proto/build.proto
+
+env_vars: {
+    key: "INSTALL_LIBRARY_FROM_SOURCE"
+    value: "True"
+}
\ No newline at end of file
diff --git a/.kokoro/samples/python3.8/periodic-head.cfg b/.kokoro/samples/python3.8/periodic-head.cfg
new file mode 100644
index 0000000000..f9cfcd33e0
--- /dev/null
+++ b/.kokoro/samples/python3.8/periodic-head.cfg
@@ -0,0 +1,11 @@
+# Format: //devtools/kokoro/config/proto/build.proto
+
+env_vars: {
+    key: "INSTALL_LIBRARY_FROM_SOURCE"
+    value: "True"
+}
+
+env_vars: {
+    key: "TRAMPOLINE_BUILD_FILE"
+    value: "github/python-pubsub/.kokoro/test-samples-against-head.sh"
+}
diff --git a/.kokoro/samples/python3.8/periodic.cfg b/.kokoro/samples/python3.8/periodic.cfg
new file mode 100644
index 0000000000..50fec96497
--- /dev/null
+++ b/.kokoro/samples/python3.8/periodic.cfg
@@ -0,0 +1,6 @@
+# Format: //devtools/kokoro/config/proto/build.proto
+
+env_vars: {
+    key: "INSTALL_LIBRARY_FROM_SOURCE"
+    value: "False"
+}
\ No newline at end of file
diff --git a/.kokoro/samples/python3.8/presubmit.cfg b/.kokoro/samples/python3.8/presubmit.cfg
new file mode 100644
index 0000000000..a1c8d9759c
--- /dev/null
+++ b/.kokoro/samples/python3.8/presubmit.cfg
@@ -0,0 +1,6 @@
+# Format: //devtools/kokoro/config/proto/build.proto
+
+env_vars: {
+    key: "INSTALL_LIBRARY_FROM_SOURCE"
+    value: "True"
+}
\ No newline at end of file
diff --git a/.kokoro/samples/python3.9/common.cfg b/.kokoro/samples/python3.9/common.cfg
new file mode 100644
index 0000000000..0c8833cfa5
--- /dev/null
+++ b/.kokoro/samples/python3.9/common.cfg
@@ -0,0 +1,40 @@
+# Format: //devtools/kokoro/config/proto/build.proto
+
+# Build logs will be here
+action {
+  define_artifacts {
+    regex: "**/*sponge_log.xml"
+  }
+}
+
+# Specify which tests to run
+env_vars: {
+    key: "RUN_TESTS_SESSION"
+    value: "py-3.9"
+}
+
+# Declare build specific Cloud project.
+env_vars: {
+    key: "BUILD_SPECIFIC_GCLOUD_PROJECT"
+    value: "python-docs-samples-tests-py39"
+}
+
+env_vars: {
+    key: "TRAMPOLINE_BUILD_FILE"
+    value: "github/python-spanner-django/.kokoro/test-samples.sh"
+}
+
+# Configure the docker image for kokoro-trampoline.
+env_vars: {
+    key: "TRAMPOLINE_IMAGE"
+    value: "gcr.io/cloud-devrel-kokoro-resources/python-samples-testing-docker"
+}
+
+# Download secrets for samples
+gfile_resources: "/bigstore/cloud-devrel-kokoro-resources/python-docs-samples"
+
+# Download trampoline resources.
+gfile_resources: "/bigstore/cloud-devrel-kokoro-resources/trampoline"
+
+# Use the trampoline script to run in docker.
+build_file: "python-spanner-django/.kokoro/trampoline.sh"
\ No newline at end of file
diff --git a/.kokoro/samples/python3.9/continuous.cfg b/.kokoro/samples/python3.9/continuous.cfg
new file mode 100644
index 0000000000..a1c8d9759c
--- /dev/null
+++ b/.kokoro/samples/python3.9/continuous.cfg
@@ -0,0 +1,6 @@
+# Format: //devtools/kokoro/config/proto/build.proto
+
+env_vars: {
+    key: "INSTALL_LIBRARY_FROM_SOURCE"
+    value: "True"
+}
\ No newline at end of file
diff --git a/.kokoro/samples/python3.9/periodic-head.cfg b/.kokoro/samples/python3.9/periodic-head.cfg
new file mode 100644
index 0000000000..f9cfcd33e0
--- /dev/null
+++ b/.kokoro/samples/python3.9/periodic-head.cfg
@@ -0,0 +1,11 @@
+# Format: //devtools/kokoro/config/proto/build.proto
+
+env_vars: {
+    key: "INSTALL_LIBRARY_FROM_SOURCE"
+    value: "True"
+}
+
+env_vars: {
+    key: "TRAMPOLINE_BUILD_FILE"
+    value: "github/python-pubsub/.kokoro/test-samples-against-head.sh"
+}
diff --git a/.kokoro/samples/python3.9/periodic.cfg b/.kokoro/samples/python3.9/periodic.cfg
new file mode 100644
index 0000000000..50fec96497
--- /dev/null
+++ b/.kokoro/samples/python3.9/periodic.cfg
@@ -0,0 +1,6 @@
+# Format: //devtools/kokoro/config/proto/build.proto
+
+env_vars: {
+    key: "INSTALL_LIBRARY_FROM_SOURCE"
+    value: "False"
+}
\ No newline at end of file
diff --git a/.kokoro/samples/python3.9/presubmit.cfg b/.kokoro/samples/python3.9/presubmit.cfg
new file mode 100644
index 0000000000..a1c8d9759c
--- /dev/null
+++ b/.kokoro/samples/python3.9/presubmit.cfg
@@ -0,0 +1,6 @@
+# Format: //devtools/kokoro/config/proto/build.proto
+
+env_vars: {
+    key: "INSTALL_LIBRARY_FROM_SOURCE"
+    value: "True"
+}
\ No newline at end of file
diff --git a/.kokoro/test-samples-against-head.sh b/.kokoro/test-samples-against-head.sh
new file mode 100755
index 0000000000..104d0e40bb
--- /dev/null
+++ b/.kokoro/test-samples-against-head.sh
@@ -0,0 +1,21 @@
+#!/bin/bash
+# Copyright 2021 Google LLC
+#
+# Use of this source code is governed by a BSD-style
+# license that can be found in the LICENSE file or at
+# https://developers.google.com/open-source/licenses/bsd
+
+
+# A customized test runner for samples.
+#
+# For periodic builds, you can specify this file for testing against head.
+
+# `-e` enables the script to automatically fail when a command fails
+# `-o pipefail` sets the exit code to the rightmost comment to exit with a non-zero
+set -eo pipefail
+# Enables `**` to include files nested inside sub-folders
+shopt -s globstar
+
+cd github/python-spanner-django
+
+exec .kokoro/test-samples-impl.sh
diff --git a/.kokoro/test-samples-impl.sh b/.kokoro/test-samples-impl.sh
new file mode 100755
index 0000000000..595dca8b0d
--- /dev/null
+++ b/.kokoro/test-samples-impl.sh
@@ -0,0 +1,94 @@
+#!/bin/bash
+# Copyright 2021 Google LLC
+#
+# Use of this source code is governed by a BSD-style
+# license that can be found in the LICENSE file or at
+# https://developers.google.com/open-source/licenses/bsd
+
+
+# `-e` enables the script to automatically fail when a command fails
+# `-o pipefail` sets the exit code to the rightmost comment to exit with a non-zero
+set -eo pipefail
+# Enables `**` to include files nested inside sub-folders
+shopt -s globstar
+
+# Exit early if samples don't exist
+if ! find samples -name 'requirements.txt' | grep -q .; then
+  echo "No tests run. './samples/**/requirements.txt' not found"
+  exit 0
+fi
+
+# Disable buffering, so that the logs stream through.
+export PYTHONUNBUFFERED=1
+
+# Debug: show build environment
+env | grep KOKORO
+
+# Install nox
+python3.6 -m pip install --upgrade --quiet nox
+
+# Use secrets acessor service account to get secrets
+if [[ -f "${KOKORO_GFILE_DIR}/secrets_viewer_service_account.json" ]]; then
+    gcloud auth activate-service-account \
+	   --key-file="${KOKORO_GFILE_DIR}/secrets_viewer_service_account.json" \
+	   --project="cloud-devrel-kokoro-resources"
+fi
+
+# This script will create 3 files:
+# - testing/test-env.sh
+# - testing/service-account.json
+# - testing/client-secrets.json
+./scripts/decrypt-secrets.sh
+
+source ./testing/test-env.sh
+export GOOGLE_APPLICATION_CREDENTIALS=$(pwd)/testing/service-account.json
+
+# For cloud-run session, we activate the service account for gcloud sdk.
+gcloud auth activate-service-account \
+       --key-file "${GOOGLE_APPLICATION_CREDENTIALS}"
+
+export GOOGLE_CLIENT_SECRETS=$(pwd)/testing/client-secrets.json
+
+echo -e "\n******************** TESTING PROJECTS ********************"
+
+# Switch to 'fail at end' to allow all tests to complete before exiting.
+set +e
+# Use RTN to return a non-zero value if the test fails.
+RTN=0
+ROOT=$(pwd)
+# Find all requirements.txt in the samples directory (may break on whitespace).
+for file in samples/**/requirements.txt; do
+    cd "$ROOT"
+    # Navigate to the project folder.
+    file=$(dirname "$file")
+    cd "$file"
+
+    echo "------------------------------------------------------------"
+    echo "- testing $file"
+    echo "------------------------------------------------------------"
+
+    # Use nox to execute the tests for the project.
+    python3.6 -m nox -s "$RUN_TESTS_SESSION"
+    EXIT=$?
+
+    # If this is a periodic build, send the test log to the FlakyBot.
+    # See https://github.com/googleapis/repo-automation-bots/tree/main/packages/flakybot.
+    if [[ $KOKORO_BUILD_ARTIFACTS_SUBDIR = *"periodic"* ]]; then
+      chmod +x $KOKORO_GFILE_DIR/linux_amd64/flakybot
+      $KOKORO_GFILE_DIR/linux_amd64/flakybot
+    fi
+
+    if [[ $EXIT -ne 0 ]]; then
+      RTN=1
+      echo -e "\n Testing failed: Nox returned a non-zero exit code. \n"
+    else
+      echo -e "\n Testing completed.\n"
+    fi
+
+done
+cd "$ROOT"
+
+# Workaround for Kokoro permissions issue: delete secrets
+rm testing/{test-env.sh,client-secrets.json,service-account.json}
+
+exit "$RTN"
diff --git a/.kokoro/test-samples.sh b/.kokoro/test-samples.sh
new file mode 100755
index 0000000000..64bd21dd92
--- /dev/null
+++ b/.kokoro/test-samples.sh
@@ -0,0 +1,39 @@
+#!/bin/bash
+# Copyright 2021 Google LLC
+#
+# Use of this source code is governed by a BSD-style
+# license that can be found in the LICENSE file or at
+# https://developers.google.com/open-source/licenses/bsd
+
+
+# The default test runner for samples.
+#
+# For periodic builds, we rewinds the repo to the latest release, and
+# run test-samples-impl.sh.
+
+# `-e` enables the script to automatically fail when a command fails
+# `-o pipefail` sets the exit code to the rightmost comment to exit with a non-zero
+set -eo pipefail
+# Enables `**` to include files nested inside sub-folders
+shopt -s globstar
+
+cd github/python-spanner-django
+
+# Run periodic samples tests at latest release
+if [[ $KOKORO_BUILD_ARTIFACTS_SUBDIR = *"periodic"* ]]; then
+    # preserving the test runner implementation.
+    cp .kokoro/test-samples-impl.sh "${TMPDIR}/test-samples-impl.sh"
+    echo "--- IMPORTANT IMPORTANT IMPORTANT ---"
+    echo "Now we rewind the repo back to the latest release..."
+    LATEST_RELEASE=$(git describe --abbrev=0 --tags)
+    git checkout $LATEST_RELEASE
+    echo "The current head is: "
+    echo $(git rev-parse --verify HEAD)
+    echo "--- IMPORTANT IMPORTANT IMPORTANT ---"
+    # move back the test runner implementation if there's no file.
+    if [ ! -f .kokoro/test-samples-impl.sh ]; then
+	cp "${TMPDIR}/test-samples-impl.sh" .kokoro/test-samples-impl.sh
+    fi
+fi
+
+exec .kokoro/test-samples-impl.sh
diff --git a/.kokoro/trampoline.sh b/.kokoro/trampoline.sh
index 8f0237f322..d42a40acbb 100755
--- a/.kokoro/trampoline.sh
+++ b/.kokoro/trampoline.sh
@@ -1,23 +1,20 @@
 #!/bin/bash
-# Copyright 2020 Google LLC.
+# Copyright 2017 Google LLC
 #
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#      http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
+# Use of this source code is governed by a BSD-style
+# license that can be found in the LICENSE file or at
+# https://developers.google.com/open-source/licenses/bsd
 
 set -eo pipefail
 
-python3 "${KOKORO_GFILE_DIR}/trampoline_v1.py"  || ret_code=$?
-
-chmod +x ${KOKORO_GFILE_DIR}/trampoline_cleanup.sh
-${KOKORO_GFILE_DIR}/trampoline_cleanup.sh || true
+# Always run the cleanup script, regardless of the success of bouncing into
+# the container.
+function cleanup() {
+    chmod +x ${KOKORO_GFILE_DIR}/trampoline_cleanup.sh
+    ${KOKORO_GFILE_DIR}/trampoline_cleanup.sh
+    echo "cleanup";
+}
+trap cleanup EXIT
 
-exit ${ret_code}
+$(dirname $0)/populate-secrets.sh # Secret Manager secrets.
+python3 "${KOKORO_GFILE_DIR}/trampoline_v1.py"
\ No newline at end of file
diff --git a/.kokoro/trampoline_v2.sh b/.kokoro/trampoline_v2.sh
index 4af6cdc26d..591faf816e 100755
--- a/.kokoro/trampoline_v2.sh
+++ b/.kokoro/trampoline_v2.sh
@@ -1,17 +1,9 @@
 #!/usr/bin/env bash
 # Copyright 2020 Google LLC
 #
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#      http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
+# Use of this source code is governed by a BSD-style
+# license that can be found in the LICENSE file or at
+# https://developers.google.com/open-source/licenses/bsd
 
 # trampoline_v2.sh
 #
diff --git a/.trampolinerc b/.trampolinerc
index 28037bbb86..383b6ec89f 100644
--- a/.trampolinerc
+++ b/.trampolinerc
@@ -1,4 +1,4 @@
-# Copyright 2021 Google LLC
+# Copyright 2020 Google LLC
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8d1d5d4875..a370dd14c0 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,35 @@
 # Changelog
 
+## 2.2.1b3 (2021-07-30)
+
+### Miscellaneous Chores
+- release 2.2.1b3 ([de23f65](https://www.github.com/googleapis/python-spanner-django/commit/de23f65))
+- Update repo to say beta release instead of alpha ([#691](https://www.github.com/googleapis/python-spanner-django/issues/691)) ([2144d09](https://www.github.com/googleapis/python-spanner-django/commit/2144d09))
+
+
+## 2.2.1b2 (2021-07-27)
+
+
+### Features
+- Added support for check constraint ([#679](https://www.github.com/googleapis/python-spanner-django/issues/679)) ([42352c0](https://www.github.com/googleapis/python-spanner-django/commit/42352c0))
+- Add open telemetry trace in schema and related unit tests ([#648](https://www.github.com/googleapis/python-spanner-django/issues/648)) ([fc51086](https://www.github.com/googleapis/python-spanner-django/commit/fc51086))
+
+
+### Bug Fixes
+- updated assets to have text background so it works with dark mode ([#674](https://www.github.com/googleapis/python-spanner-django/issues/674)) ([306eeba](https://www.github.com/googleapis/python-spanner-django/commit/306eeba))
+- updated assets to have text background so it works with dark mode ([#671](https://www.github.com/googleapis/python-spanner-django/issues/671)) ([0f99938](https://www.github.com/googleapis/python-spanner-django/commit/0f99938))
+- bump version number after 2.2.1b1 release ([#652](https://www.github.com/googleapis/python-spanner-django/issues/652)) ([287b893](https://www.github.com/googleapis/python-spanner-django/commit/287b893))
+
+
+### Documentation
+- update docs to show decimal field support and check constraints but no support for unsigned data type ([#683](https://www.github.com/googleapis/python-spanner-django/issues/683)) ([74f2269](https://www.github.com/googleapis/python-spanner-django/commit/74f2269))
+- Adding documentation for GA ([#665](https://www.github.com/googleapis/python-spanner-django/issues/665)) ([216c2e0](https://www.github.com/googleapis/python-spanner-django/commit/216c2e0))
+
+
+### Miscellaneous Chores
+- release 2.2.1b2 ([#685](https://www.github.com/googleapis/python-spanner-django/issues/685)) ([96a809d](https://www.github.com/googleapis/python-spanner-django/commit/96a809d))
+- fix release build ([#659](https://www.github.com/googleapis/python-spanner-django/issues/659)) ([11bc9c2](https://www.github.com/googleapis/python-spanner-django/commit/11bc9c2))
+
 ## 2.2.1b1 (2021-06-17)
 
 
diff --git a/README.rst b/README.rst
index e79e23cd91..62739a3182 100644
--- a/README.rst
+++ b/README.rst
@@ -220,13 +220,13 @@ How it works
 Overall design
 ~~~~~~~~~~~~~~
 
-.. figure:: https://raw.githubusercontent.com/googleapis/python-spanner-django/master/assets/overview.png
+.. figure:: https://raw.githubusercontent.com/googleapis/python-spanner-django/main/assets/overview.png
    :alt: "Overall Design"
 
 Internals
 ~~~~~~~~~
 
-.. figure:: https://raw.githubusercontent.com/googleapis/python-spanner-django/master/assets/internals.png
+.. figure:: https://raw.githubusercontent.com/googleapis/python-spanner-django/main/assets/internals.png
    :alt: "Internals"
 
 
@@ -247,11 +247,11 @@ HOW TO CONTRIBUTE
 
 Contributions to this library are always welcome and highly encouraged.
 
-See `CONTRIBUTING <https://github.com/googleapis/python-spanner-django/blob/master/CONTRIBUTING.md>`_ for more information on how to get started.
+See `CONTRIBUTING <https://github.com/googleapis/python-spanner-django/blob/main/CONTRIBUTING.md>`_ for more information on how to get started.
 
 Please note that this project is released with a Contributor Code of Conduct.
 By participating in this project you agree to abide by its terms. See the `Code 
-of Conduct <https://github.com/googleapis/python-spanner-django/blob/master/CODE_OF_CONDUCT.md>`_ for more information.
+of Conduct <https://github.com/googleapis/python-spanner-django/blob/main/CODE_OF_CONDUCT.md>`_ for more information.
 
 Current limitations
 -------------------
@@ -283,23 +283,16 @@ were created.
 Spanner does not support ``ON DELETE CASCADE`` when creating foreign-key
 constraints, so this is not supported in ``django-google-spanner``.
 
-Check constraints aren't supported
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+``Unsigned`` datatypes are not supported
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-Spanner does not support ``CHECK`` constraints so one isn't created for
-`PositiveIntegerField
+Spanner does not support ``Unsigned`` datatypes so `PositiveIntegerField
 <https://docs.djangoproject.com/en/stable/ref/models/fields/#positiveintegerfield>`__
-and `CheckConstraint
-<https://docs.djangoproject.com/en/stable/ref/models/constraints/#checkconstraint>`__
-can't be used.
-
-No native support for ``DecimalField``
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-Spanner's support for `Decimal <https://www.python.org/dev/peps/pep-0327/>`__
-types is limited to
-`NUMERIC <https://cloud.google.com/spanner/docs/data-types#numeric_types>`__
-precision. Higher-precision values can be stored as strings instead.
+and `PositiveSmallIntegerField
+<https://docs.djangoproject.com/en/3.2/ref/models/fields/#positivesmallintegerfield>`__
+are both stored as `Integer type
+<https://cloud.google.com/spanner/docs/data-types#integer_type>`__
+.
 
 ``Meta.order_with_respect_to`` model option isn't supported
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
diff --git a/assets/overview.png b/assets/overview.png
index a556727a18..1fc2933e51 100644
Binary files a/assets/overview.png and b/assets/overview.png differ
diff --git a/django_spanner/__init__.py b/django_spanner/__init__.py
index 861e3abb94..a26703d5a5 100644
--- a/django_spanner/__init__.py
+++ b/django_spanner/__init__.py
@@ -5,6 +5,7 @@
 # https://developers.google.com/open-source/licenses/bsd
 
 import datetime
+import os
 
 # Monkey-patch AutoField to generate a random value since Cloud Spanner can't
 # do that.
@@ -24,6 +25,8 @@
 
 __version__ = pkg_resources.get_distribution("django-google-spanner").version
 
+USE_EMULATOR = os.getenv("SPANNER_EMULATOR_HOST") is not None
+
 check_django_compatability()
 register_expressions()
 register_functions()
diff --git a/django_spanner/features.py b/django_spanner/features.py
index af7e4c1131..a0ae6299c3 100644
--- a/django_spanner/features.py
+++ b/django_spanner/features.py
@@ -38,6 +38,8 @@ class DatabaseFeatures(BaseDatabaseFeatures):
     skip_tests = (
         # No foreign key constraints in Spanner.
         "backends.tests.FkConstraintsTests.test_check_constraints",
+        # Spanner does not support empty list of DML statement.
+        "backends.tests.BackendTestCase.test_cursor_executemany_with_empty_params_list",
         "fixtures_regress.tests.TestFixtures.test_loaddata_raises_error_when_fixture_has_invalid_foreign_key",
         # No Django transaction management in Spanner.
         "basic.tests.SelectOnSaveTests.test_select_on_save_lying_update",
@@ -184,7 +186,7 @@ class DatabaseFeatures(BaseDatabaseFeatures):
         "db_functions.comparison.test_cast.CastTests.test_cast_to_decimal_field",
         "model_fields.test_decimalfield.DecimalFieldTests.test_fetch_from_db_without_float_rounding",
         "model_fields.test_decimalfield.DecimalFieldTests.test_roundtrip_with_trailing_zeros",
-        # No CHECK constraints in Spanner.
+        # Spanner does not support unsigned integer field.
         "model_fields.test_integerfield.PositiveIntegerFieldTests.test_negative_values",
         # Spanner doesn't support the variance the standard deviation database
         # functions:
diff --git a/django_spanner/schema.py b/django_spanner/schema.py
index d28dcc4f6e..247358857a 100644
--- a/django_spanner/schema.py
+++ b/django_spanner/schema.py
@@ -7,6 +7,7 @@
 from django.db import NotSupportedError
 from django.db.backends.base.schema import BaseDatabaseSchemaEditor
 from django_spanner._opentelemetry_tracing import trace_call
+from django_spanner import USE_EMULATOR
 
 
 class DatabaseSchemaEditor(BaseDatabaseSchemaEditor):
@@ -472,8 +473,13 @@ def _alter_column_type_sql(self, model, old_field, new_field, new_type):
         )
 
     def _check_sql(self, name, check):
-        # Spanner doesn't support CHECK constraints.
-        return None
+        # Emulator does not support check constraints yet.
+        if USE_EMULATOR:
+            return None
+        return self.sql_constraint % {
+            "name": self.quote_name(name),
+            "constraint": self.sql_check_constraint % {"check": check},
+        }
 
     def _unique_sql(self, model, fields, name, condition=None):
         # Inline constraints aren't supported, so create the index separately.
diff --git a/docs/changelog.md b/docs/changelog.md
deleted file mode 100644
index 825c32f0d0..0000000000
--- a/docs/changelog.md
+++ /dev/null
@@ -1 +0,0 @@
-# Changelog
diff --git a/docs/changelog.md b/docs/changelog.md
new file mode 120000
index 0000000000..04c99a55ca
--- /dev/null
+++ b/docs/changelog.md
@@ -0,0 +1 @@
+../CHANGELOG.md
\ No newline at end of file
diff --git a/docs/example_from_scratch.md b/docs/example_from_scratch.md
new file mode 120000
index 0000000000..1e40292b5e
--- /dev/null
+++ b/docs/example_from_scratch.md
@@ -0,0 +1 @@
+../examples/from-scratch/README.md
\ No newline at end of file
diff --git a/docs/example_healthchecks.md b/docs/example_healthchecks.md
new file mode 120000
index 0000000000..08983d890b
--- /dev/null
+++ b/docs/example_healthchecks.md
@@ -0,0 +1 @@
+../examples/healthchecks/README.md
\ No newline at end of file
diff --git a/docs/samples.rst b/docs/samples.rst
index 4d9ef417a2..09d8c37590 100644
--- a/docs/samples.rst
+++ b/docs/samples.rst
@@ -1,24 +1,12 @@
-Sample Code
-####################################
+Sample Examples
+###############
 
-Create and register your first model
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-To define your database layout create a models file in your app folder and add the relevant 
-classes to it. Spanner works exactly like any other database you may have used with Django. 
-Here is a simple example you can run with Spanner. In our poll application below we create 
-the following two models:
+django-spanner for Django tutorial
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-.. code:: python
+This `Example <example_from_scratch.html>`_ shows how to use django-spanner for Cloud Spanner as a backend database for `healthchecks.io <https://healthchecks.io>`_ 
 
-    from django.db import models
-    
-    class Question(models.Model):
-    question_text = models.CharField(max_length=200)
-    pub_date = models.DateTimeField('date published')
-    def __str__(self):
-        return str(self.rating)
-    
-    class Choice(models.Model):
-    question = models.ForeignKey(Question, on_delete=models.CASCADE)
-    choice_text = models.CharField(max_length=200)
-    votes = models.IntegerField(default=0)
+django-spanner on healthchecks.io
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+This `Example <example_healthchecks.html>`_ shows how to use django-spanner for Cloud Spanner as a backend database for `Django's tutorials <https://docs.djangoproject.com/en/2.2/intro/tutorial01/>`_ 
diff --git a/noxfile.py b/noxfile.py
index a5c05e7a02..3b51d73841 100644
--- a/noxfile.py
+++ b/noxfile.py
@@ -43,7 +43,7 @@ def lint(session):
     session.run("flake8", "django_spanner", "tests")
 
 
-@nox.session(python="3.6")
+@nox.session(python=DEFAULT_PYTHON_VERSION)
 def blacken(session):
     """Run black.
 
diff --git a/owlbot.py b/owlbot.py
new file mode 100644
index 0000000000..d0087b4c0b
--- /dev/null
+++ b/owlbot.py
@@ -0,0 +1,42 @@
+# Copyright 2021 Google LLC
+#
+# Use of this source code is governed by a BSD-style
+# license that can be found in the LICENSE file or at
+# https://developers.google.com/open-source/licenses/bsd
+
+"""This script is used to synthesize generated parts of this library."""
+import re
+
+import synthtool as s
+import synthtool.gcp as gcp
+
+# ----------------------------------------------------------------------------
+# Add templated files
+# ----------------------------------------------------------------------------
+templated_files = gcp.CommonTemplates().py_library(microgenerator=True)
+
+# Just move templates for building docs and releases
+# Presubmit and continuous are configured differently
+s.move(templated_files / ".trampolinerc")
+s.move(templated_files / ".kokoro" / "docker")
+s.move(templated_files / ".kokoro" / "docs")
+s.move(templated_files / ".kokoro" / "release.sh")
+s.move(templated_files / ".kokoro" / "trampoline_v2.sh")
+s.move(templated_files / ".kokoro" / "trampoline.sh")
+s.move(templated_files / ".kokoro" / "populate-secrets.sh")
+s.move(templated_files / ".kokoro" / "release")
+
+# Replace the Apache Licenses in the `.kokoro` directory
+# with the BSD license expected in this repository
+s.replace(
+    ".kokoro/**/*",
+    "# Copyright.*(\d{4}).*# limitations under the License\.",
+    """# Copyright \g<1> Google LLC
+#
+# Use of this source code is governed by a BSD-style
+# license that can be found in the LICENSE file or at
+# https://developers.google.com/open-source/licenses/bsd""",
+    flags=re.DOTALL
+)
+
+s.shell.run(["nox", "-s", "blacken"], hide_output=False)
diff --git a/setup.py b/setup.py
index c310fda167..a3143566bb 100644
--- a/setup.py
+++ b/setup.py
@@ -16,7 +16,7 @@
 # 'Development Status :: 3 - Alpha'
 # 'Development Status :: 4 - Beta'
 # 'Development Status :: 5 - Production/Stable'
-release_status = "Development Status :: 3 - Alpha"
+release_status = "Development Status :: 4 - Beta"
 dependencies = ["sqlparse >= 0.3.0", "google-cloud-spanner >= 3.0.0"]
 extras = {
     "tracing": [
diff --git a/tests/performance/__init__.py b/tests/performance/__init__.py
new file mode 100644
index 0000000000..529352b757
--- /dev/null
+++ b/tests/performance/__init__.py
@@ -0,0 +1,5 @@
+# Copyright 2021 Google LLC
+#
+# Use of this source code is governed by a BSD-style
+# license that can be found in the LICENSE file or at
+# https://developers.google.com/open-source/licenses/bsd
diff --git a/tests/performance/django_spanner/__init__.py b/tests/performance/django_spanner/__init__.py
new file mode 100644
index 0000000000..529352b757
--- /dev/null
+++ b/tests/performance/django_spanner/__init__.py
@@ -0,0 +1,5 @@
+# Copyright 2021 Google LLC
+#
+# Use of this source code is governed by a BSD-style
+# license that can be found in the LICENSE file or at
+# https://developers.google.com/open-source/licenses/bsd
diff --git a/tests/performance/django_spanner/models.py b/tests/performance/django_spanner/models.py
new file mode 100644
index 0000000000..d387a6ef86
--- /dev/null
+++ b/tests/performance/django_spanner/models.py
@@ -0,0 +1,14 @@
+# Copyright 2021 Google LLC
+#
+# Use of this source code is governed by a BSD-style
+# license that can be found in the LICENSE file or at
+# https://developers.google.com/open-source/licenses/bsd
+
+from django.db import models
+
+
+class Author(models.Model):
+    id = models.IntegerField(primary_key=True)
+    first_name = models.CharField(max_length=20)
+    last_name = models.CharField(max_length=20)
+    rating = models.CharField(max_length=50)
diff --git a/tests/performance/django_spanner/test_benchmark.py b/tests/performance/django_spanner/test_benchmark.py
new file mode 100644
index 0000000000..31dd8f2987
--- /dev/null
+++ b/tests/performance/django_spanner/test_benchmark.py
@@ -0,0 +1,296 @@
+# Copyright 2021 Google LLC
+#
+# Use of this source code is governed by a BSD-style
+# license that can be found in the LICENSE file or at
+# https://developers.google.com/open-source/licenses/bsd
+
+import random
+import time
+import unittest
+
+import pandas as pd
+import pytest
+from django.db import connection
+from google.api_core.exceptions import Aborted
+from google.cloud import spanner_dbapi
+from google.cloud.spanner_v1 import Client, KeySet
+
+from tests.performance.django_spanner.models import Author
+from tests.settings import DATABASE_NAME, INSTANCE_ID
+from tests.system.django_spanner.utils import setup_database, setup_instance
+
+
+def measure_execution_time(function):
+    """Decorator to measure a wrapped method execution time."""
+
+    def wrapper(self, measures):
+        """Execute the wrapped method and measure its execution time.
+        Args:
+            measures (dict): Test cases and their execution time.
+        """
+        t_start = time.time()
+        try:
+            function(self)
+            measures[function.__name__] = round(time.time() - t_start, 4)
+        except Aborted:
+            measures[function.__name__] = 0
+
+    return wrapper
+
+
+def insert_one_row(transaction, one_row):
+    """A transaction-function for the original Spanner client.
+    Inserts a single row into a database and then fetches it back.
+    """
+    transaction.execute_update(
+        "INSERT Author (id, first_name, last_name, rating) "
+        " VALUES {}".format(str(one_row))
+    )
+    last_name = transaction.execute_sql(
+        "SELECT last_name FROM Author WHERE id=1"
+    ).one()[0]
+    if last_name != "Allison":
+        raise ValueError("Received invalid last name: " + last_name)
+
+
+def insert_many_rows(transaction, many_rows):
+    """A transaction-function for the original Spanner client.
+    Insert 100 rows into a database.
+    """
+    statements = []
+    for row in many_rows:
+        statements.append(
+            "INSERT Author (id, first_name, last_name, rating) "
+            " VALUES {}".format(str(row))
+        )
+    _, count = transaction.batch_update(statements)
+    if sum(count) != 99:
+        raise ValueError("Wrong number of inserts: " + str(sum(count)))
+
+
+class DjangoBenchmarkTest:
+    """The Django performace testing class."""
+
+    def __init__(self):
+        with connection.schema_editor() as editor:
+            # Create the tables
+            editor.create_model(Author)
+
+        self._many_rows = []
+        self._many_rows2 = []
+        for i in range(99):
+            num = round(random.randint(0, 100000000))
+            self._many_rows.append(Author(num, "Pete", "Allison", "2.1"))
+            num2 = round(random.randint(0, 100000000))
+            self._many_rows2.append(Author(num2, "Pete", "Allison", "2.1"))
+
+    @measure_execution_time
+    def insert_one_row_with_fetch_after(self):
+        author_kent = Author(
+            id=2, first_name="Pete", last_name="Allison", rating="2.1",
+        )
+        author_kent.save()
+        last_name = Author.objects.get(pk=author_kent.id).last_name
+        if last_name != "Allison":
+            raise ValueError("Received invalid last name: " + last_name)
+
+    @measure_execution_time
+    def insert_many_rows(self):
+        for row in self._many_rows:
+            row.save()
+
+    @measure_execution_time
+    def insert_many_rows_with_mutations(self):
+        Author.objects.bulk_create(self._many_rows2)
+
+    @measure_execution_time
+    def read_one_row(self):
+        row = Author.objects.all().first()
+        if row is None:
+            raise ValueError("No rows read")
+
+    @measure_execution_time
+    def select_many_rows(self):
+        rows = Author.objects.all()
+        if len(rows) != 100:
+            raise ValueError("Wrong number of rows read")
+
+    def _cleanup(self):
+        """Drop the test table."""
+        with connection.schema_editor() as editor:
+            # delete the table
+            editor.delete_model(Author)
+
+    def run(self):
+        """Execute every test case."""
+        measures = {}
+        for method in (
+            self.insert_one_row_with_fetch_after,
+            self.read_one_row,
+            self.insert_many_rows,
+            self.select_many_rows,
+            self.insert_many_rows_with_mutations,
+        ):
+            method(measures)
+        self._cleanup()
+        return measures
+
+
+class SpannerBenchmarkTest:
+    """The Spanner performace testing class."""
+
+    def __init__(self):
+        self._create_table()
+        self._one_row = (
+            1,
+            "Pete",
+            "Allison",
+            "2.1",
+        )
+        self._client = Client()
+        self._instance = self._client.instance(INSTANCE_ID)
+        self._database = self._instance.database(DATABASE_NAME)
+
+        self._many_rows = []
+        self._many_rows2 = []
+        for i in range(99):
+            num = round(random.randint(0, 100000000))
+            self._many_rows.append((num, "Pete", "Allison", "2.1"))
+            num2 = round(random.randint(0, 100000000))
+            self._many_rows2.append((num2, "Pete", "Allison", "2.1"))
+
+        # initiate a session
+        with self._database.snapshot():
+            pass
+
+    def _create_table(self):
+        """Create a table for performace testing."""
+        conn = spanner_dbapi.connect(INSTANCE_ID, DATABASE_NAME)
+        conn.database.update_ddl(
+            [
+                """
+CREATE TABLE Author (
+    id INT64,
+    first_name STRING(20),
+    last_name STRING(20),
+    rating STRING(50),
+) PRIMARY KEY (id)
+        """
+            ]
+        ).result(120)
+
+        conn.close()
+
+    @measure_execution_time
+    def insert_one_row_with_fetch_after(self):
+        self._database.run_in_transaction(insert_one_row, self._one_row)
+
+    @measure_execution_time
+    def insert_many_rows(self):
+        self._database.run_in_transaction(insert_many_rows, self._many_rows)
+
+    @measure_execution_time
+    def insert_many_rows_with_mutations(self):
+        with self._database.batch() as batch:
+            batch.insert(
+                table="Author",
+                columns=("id", "first_name", "last_name", "rating"),
+                values=self._many_rows2,
+            )
+
+    @measure_execution_time
+    def read_one_row(self):
+        with self._database.snapshot() as snapshot:
+            keyset = KeySet(all_=True)
+            snapshot.read(
+                table="Author",
+                columns=("id", "first_name", "last_name", "rating"),
+                keyset=keyset,
+            ).one()
+
+    @measure_execution_time
+    def select_many_rows(self):
+        with self._database.snapshot() as snapshot:
+            rows = list(
+                snapshot.execute_sql("SELECT * FROM Author ORDER BY last_name")
+            )
+            if len(rows) != 100:
+                raise ValueError("Wrong number of rows read")
+
+    def _cleanup(self):
+        """Drop the test table."""
+        conn = spanner_dbapi.connect(INSTANCE_ID, DATABASE_NAME)
+        conn.database.update_ddl(["DROP TABLE Author"])
+        conn.close()
+
+    def run(self):
+        """Execute every test case."""
+        measures = {}
+        for method in (
+            self.insert_one_row_with_fetch_after,
+            self.read_one_row,
+            self.insert_many_rows,
+            self.select_many_rows,
+            self.insert_many_rows_with_mutations,
+        ):
+            method(measures)
+        self._cleanup()
+        return measures
+
+
+@pytest.mark.django_db()
+class BenchmarkTest(unittest.TestCase):
+    def setUp(self):
+        setup_instance()
+        setup_database()
+
+    def test_run(self):
+        django_obj = pd.DataFrame(
+            columns=[
+                "insert_one_row_with_fetch_after",
+                "read_one_row",
+                "insert_many_rows",
+                "select_many_rows",
+                "insert_many_rows_with_mutations",
+            ]
+        )
+        spanner_obj = pd.DataFrame(
+            columns=[
+                "insert_one_row_with_fetch_after",
+                "read_one_row",
+                "insert_many_rows",
+                "select_many_rows",
+                "insert_many_rows_with_mutations",
+            ]
+        )
+
+        for _ in range(50):
+            django_obj = django_obj.append(
+                DjangoBenchmarkTest().run(), ignore_index=True
+            )
+            spanner_obj = spanner_obj.append(
+                SpannerBenchmarkTest().run(), ignore_index=True
+            )
+
+        avg = pd.concat(
+            [django_obj.mean(axis=0), spanner_obj.mean(axis=0)], axis=1
+        )
+        avg.columns = ["Django", "Spanner"]
+        std = pd.concat(
+            [django_obj.std(axis=0), spanner_obj.std(axis=0)], axis=1
+        )
+        std.columns = ["Django", "Spanner"]
+        err = pd.concat(
+            [django_obj.sem(axis=0), spanner_obj.sem(axis=0)], axis=1
+        )
+        err.columns = ["Django", "Spanner"]
+
+        print(
+            "Average: ",
+            avg,
+            "Standard Deviation: ",
+            std,
+            "Error:",
+            err,
+            sep="\n",
+        )
diff --git a/tests/system/django_spanner/models.py b/tests/system/django_spanner/models.py
index 5524ad8ec9..f7153ba994 100644
--- a/tests/system/django_spanner/models.py
+++ b/tests/system/django_spanner/models.py
@@ -21,3 +21,16 @@ class Number(models.Model):
 
     def __str__(self):
         return str(self.num)
+
+
+class Event(models.Model):
+    start_date = models.DateTimeField()
+    end_date = models.DateTimeField()
+
+    class Meta:
+        constraints = [
+            models.CheckConstraint(
+                check=models.Q(end_date__gt=models.F("start_date")),
+                name="check_start_date",
+            ),
+        ]
diff --git a/tests/system/django_spanner/test_check_constraint.py b/tests/system/django_spanner/test_check_constraint.py
new file mode 100644
index 0000000000..9177166ce9
--- /dev/null
+++ b/tests/system/django_spanner/test_check_constraint.py
@@ -0,0 +1,64 @@
+# Copyright 2021 Google LLC
+#
+# Use of this source code is governed by a BSD-style
+# license that can be found in the LICENSE file or at
+# https://developers.google.com/open-source/licenses/bsd
+
+from .models import Event
+from django.test import TransactionTestCase
+import datetime
+import unittest
+from django.utils import timezone
+from google.api_core.exceptions import OutOfRange
+from django.db import connection
+from django_spanner import USE_EMULATOR
+from tests.system.django_spanner.utils import (
+    setup_instance,
+    teardown_instance,
+    setup_database,
+    teardown_database,
+)
+
+
+@unittest.skipIf(
+    USE_EMULATOR, "Check Constraint is not implemented in emulator."
+)
+class TestCheckConstraint(TransactionTestCase):
+    @classmethod
+    def setUpClass(cls):
+        setup_instance()
+        setup_database()
+        with connection.schema_editor() as editor:
+            # Create the table
+            editor.create_model(Event)
+
+    @classmethod
+    def tearDownClass(cls):
+        with connection.schema_editor() as editor:
+            # delete the table
+            editor.delete_model(Event)
+        teardown_database()
+        teardown_instance()
+
+    def test_insert_valid_value(self):
+        """
+        Tests model object creation with Event model.
+        """
+        now = timezone.now()
+        now_plus_10 = now + datetime.timedelta(minutes=10)
+        event_valid = Event(start_date=now, end_date=now_plus_10)
+        event_valid.save()
+        qs1 = Event.objects.filter().values("start_date")
+        self.assertEqual(qs1[0]["start_date"], now)
+        # Delete data from Event table.
+        Event.objects.all().delete()
+
+    def test_insert_invalid_value(self):
+        """
+        Tests model object creation with invalid data in Event model.
+        """
+        now = timezone.now()
+        now_minus_1_day = now - timezone.timedelta(days=1)
+        event_invalid = Event(start_date=now, end_date=now_minus_1_day)
+        with self.assertRaises(OutOfRange):
+            event_invalid.save()
diff --git a/tests/system/django_spanner/test_decimal.py b/tests/system/django_spanner/test_decimal.py
index 73df7e796b..4155599af1 100644
--- a/tests/system/django_spanner/test_decimal.py
+++ b/tests/system/django_spanner/test_decimal.py
@@ -6,14 +6,13 @@
 
 from .models import Author, Number
 from django.test import TransactionTestCase
-from django.db import connection, ProgrammingError
+from django.db import connection
 from decimal import Decimal
 from tests.system.django_spanner.utils import (
     setup_instance,
     teardown_instance,
     setup_database,
     teardown_database,
-    USE_EMULATOR,
 )
 
 
@@ -87,12 +86,8 @@ def test_decimal_precision_limit(self):
         Tests decimal object precission limit.
         """
         num_val = Number(num=Decimal(1) / Decimal(3))
-        if USE_EMULATOR:
-            with self.assertRaises(ValueError):
-                num_val.save()
-        else:
-            with self.assertRaises(ProgrammingError):
-                num_val.save()
+        with self.assertRaises(ValueError):
+            num_val.save()
 
     def test_decimal_update(self):
         """
diff --git a/tests/system/django_spanner/utils.py b/tests/system/django_spanner/utils.py
index 7fac5166e0..3dca9db9b8 100644
--- a/tests/system/django_spanner/utils.py
+++ b/tests/system/django_spanner/utils.py
@@ -15,11 +15,12 @@
 from test_utils.retry import RetryErrors
 
 from django_spanner.creation import DatabaseCreation
+from django_spanner import USE_EMULATOR
 
 CREATE_INSTANCE = (
     os.getenv("GOOGLE_CLOUD_TESTS_CREATE_SPANNER_INSTANCE") is not None
 )
-USE_EMULATOR = os.getenv("SPANNER_EMULATOR_HOST") is not None
+
 SPANNER_OPERATION_TIMEOUT_IN_SECONDS = int(
     os.getenv("SPANNER_OPERATION_TIMEOUT_IN_SECONDS", 60)
 )
diff --git a/version.py b/version.py
index df949c65d1..32ec82411a 100644
--- a/version.py
+++ b/version.py
@@ -4,4 +4,4 @@
 # license that can be found in the LICENSE file or at
 # https://developers.google.com/open-source/licenses/bsd
 
-__version__ = "2.2.1b2"
+__version__ = "2.2.1b4"