firestore: cross-language tests (#4359)

* firestore: cross-language tests

Copied the cross-language tests from GoogleCloudPlatform/google-cloud-common
to this repo.

Generated the Python _pb2.py file for the test proto. This required some
path renaming, so I added a Makefile.

Added a unit test that reads and runs the test protos.

Sorted transform paths in get_transform_pb to make some tests pass.

Renamed tests that fail.

TODOs:
- Fix failing tests.

- Support tests of the set() method.

- Find a better place to put test_pb2.py. I don't understand
  how import paths work so I couldn't figure this out.

* create client with project, instead of adding it later

* sort update mask for tests

Author: jba

firestore/Makefile

@@ -0,0 +1,36 @@
+# This makefile builds the protos needed for cross-language Firestore tests.
+
+# Assume protoc is on the path. The proto compiler must be one that
+# supports proto3 syntax.
+PROTOC = protoc
+
+# Dependent repos.
+PROTOBUF_REPO = $(HOME)/git-repos/protobuf
+GOOGLEAPIS_REPO = $(HOME)/git-repos/googleapis
+
+TESTS_REPO = $(HOME)/git-repos/gcp/google-cloud-common
+
+TMPDIR = /tmp/python-fs-proto
+TMPDIR_FS = $(TMPDIR)/google/cloud/firestore_v1beta1/proto
+
+.PHONY: sync-protos gen-protos
+
+gen-protos: sync-protos tweak-protos
+	# TODO(jba): Put the generated proto somewhere more suitable.
+	$(PROTOC) --python_out=google/cloud/firestore_v1beta1/proto \
+		-I $(TMPDIR) \
+		-I $(PROTOBUF_REPO)/src \
+		-I $(GOOGLEAPIS_REPO) \
+		$(TMPDIR)/*.proto
+
+tweak-protos:
+	mkdir -p $(TMPDIR_FS)
+	cp $(GOOGLEAPIS_REPO)/google/firestore/v1beta1/*.proto $(TMPDIR_FS)
+	sed -i -e 's@google/firestore/v1beta1@google/cloud/firestore_v1beta1/proto@' $(TMPDIR_FS)/*.proto
+	cp $(TESTS_REPO)/testing/firestore/proto/*.proto $(TMPDIR)
+	sed -i -e 's@google/firestore/v1beta1@google/cloud/firestore_v1beta1/proto@' $(TMPDIR)/*.proto
+
+sync-protos:
+	cd $(PROTOBUF_REPO); git pull
+	cd $(GOOGLEAPIS_REPO); git pull
+	cd $(TESTS_REPO); git pull

firestore/google/cloud/firestore_v1beta1/_helpers.py

@@ -794,7 +794,8 @@ def get_transform_pb(document_path, transform_paths):
                     field_path=field_path,
                     set_to_server_value=REQUEST_TIME_ENUM,
                 )
-                for field_path in transform_paths
+                # Sort transform_paths so test comparision works.
+                for field_path in sorted(transform_paths)
             ],
         ),
     )
@@ -865,7 +866,8 @@ def pbs_for_update(client, document_path, field_updates, option):
             name=document_path,
             fields=encode_dict(update_values),
         ),
-        update_mask=common_pb2.DocumentMask(field_paths=field_paths),
+        # Sort field_paths just for comparison in tests.
+        update_mask=common_pb2.DocumentMask(field_paths=sorted(field_paths)),
     )
     # Due to the default, we don't have to check if ``None``.
     option.modify_write(update_pb)