tests: re-enable cross-language conformance tests (#205)

Leaving existing (old) conftest JSON files in place for now. in order
to  get the conftest runner working using existing semantics,
before updating the JSON files and making required changes (to use
'update_transforms', for instance) in a future PR.

Closes #95.

Co-authored-by: Christopher Wilcox <crwilcox@google.com>

Makefile_v1

@@ -11,30 +11,51 @@ GOOGLEAPIS_REPO = $(REPO_DIR)/googleapis
 TESTS_REPO = $(REPO_DIR)/conformance-tests
 TEST_PROTO_DIR = $(TESTS_REPO)/firestore/v1
 TEST_PROTO_SRC = $(TEST_PROTO_DIR)/proto/google/cloud/conformance/firestore/v1/tests.proto
+TESTDATA_DIR = `pwd`/tests/unit/v1/testdata/
 
 TMPDIR = /tmp/python-fs-proto
-TMPDIR_FS = $(TMPDIR)/google/cloud/firestore_v1/proto
+TMPDIR_FS = $(TMPDIR)/google/cloud/firestore_v1/types
 TEST_PROTO_COPY = $(TMPDIR_FS)/tests.proto
+TEST_GEN_OUT = tests/unit/v1/conformance_tests.py
+OUTDIR = /tmp/python-fs-gen
 
-.PHONY: sync-protos gen-protos
+.PHONY: sync-protos gen-protos docker-pull
 
-gen-protos: sync-protos tweak-protos
-	# TODO(jba): Put the generated proto somewhere more suitable.
-	$(PROTOC) --python_out=. \
-		-I $(TMPDIR) \
-		-I $(PROTOBUF_REPO)/src \
-		-I $(GOOGLEAPIS_REPO) \
-		$(TEST_PROTO_COPY)
+gen-protos: sync-protos tweak-protos docker-pull gen-protos-raw
+
+gen-protos-raw:
+	mkdir -p $(OUTDIR)
+	docker run \
+		--mount type=bind,source=$(TMPDIR),destination="/in",readonly \
+		--mount type=bind,source=$(OUTDIR),destination="/out" \
+		--rm \
+		--user `id -u`:`id -g` \
+	gcr.io/gapic-images/gapic-generator-python
+	cp $(OUTDIR)/google/cloud/firestore_v1/types/tests.py \
+		$(TEST_GEN_OUT)
+	sed -i -e \
+		"s@package='google.cloud.firestore_v1'@package='tests.unit.v1'@" \
+		$(TEST_GEN_OUT)
 
 tweak-protos:
 	mkdir -p $(TMPDIR_FS)
 	cp $(GOOGLEAPIS_REPO)/google/firestore/v1/*.proto $(TMPDIR_FS)
-	sed -i -e 's@google/firestore/v1@google/cloud/firestore_v1/proto@' $(TMPDIR_FS)/*.proto
+	sed -i -e 's@google/firestore/v1@google/cloud/firestore_v1/types@' $(TMPDIR_FS)/*.proto
+	sed -i -e 's@package google\.firestore\.v1@package google.cloud.firestore_v1@' $(TMPDIR_FS)/*.proto
 	cp $(TEST_PROTO_SRC) $(TEST_PROTO_COPY)
-	sed -i -e 's@package google.cloud.conformance.firestore.v1@package google.cloud.firestore_v1.proto@' $(TEST_PROTO_COPY)
-	sed -i -e 's@google/firestore/v1@google/cloud/firestore_v1/proto@' $(TEST_PROTO_COPY)
+	sed -i -e 's@package google\.cloud\.conformance\.firestore\.v1@package google.cloud.firestore_v1@' $(TEST_PROTO_COPY)
+	sed -i -e 's@google/firestore/v1@google/cloud/firestore_v1/types@' $(TEST_PROTO_COPY)
+	sed -i -e 's@google\.firestore\.v1@google.cloud.firestore_v1@' $(TEST_PROTO_COPY)
+	sed -i -e 's@Cursor@Cursor_@' $(TEST_PROTO_COPY)
 
 sync-protos:
 	cd $(PROTOBUF_REPO); git pull
 	cd $(GOOGLEAPIS_REPO); git pull
 	cd $(TESTS_REPO); git pull
+
+docker-pull:
+	docker pull gcr.io/gapic-images/gapic-generator-python:latest
+
+copy-testdata:
+	rm $(TESTDATA_DIR)/*.json
+	cp $(TEST_PROTO_DIR)/*.json $(TESTDATA_DIR)/