diff --git a/testing/constraints-3.10.txt b/testing/constraints-3.10.txt
new file mode 100644
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diff --git a/testing/constraints-3.11.txt b/testing/constraints-3.11.txt
new file mode 100644
index 0000000..e69de29
diff --git a/testing/constraints-3.6.txt b/testing/constraints-3.6.txt
new file mode 100644
index 0000000..650f2c5
--- /dev/null
+++ b/testing/constraints-3.6.txt
@@ -0,0 +1,23 @@
+# Copyright 2021 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.
+#
+# This constraints file is used to check that lower bounds
+# are correct in setup.py
+# List *all* library dependencies and extras in this file.
+# Pin the version to the lower bound.
+#
+# e.g., if setup.py has "foo >= 1.14.0, < 2.0.0dev",
+# Then this file should have foo==1.14.0
+google-api-core==1.22.2
+proto-plus==1.4.0
diff --git a/testing/constraints-3.7.txt b/testing/constraints-3.7.txt
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diff --git a/testing/constraints-3.8.txt b/testing/constraints-3.8.txt
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index 0000000..e69de29
diff --git a/testing/constraints-3.9.txt b/testing/constraints-3.9.txt
new file mode 100644
index 0000000..e69de29