impl(bigtable): mocks for streaming read rpcs (#8836)

Author: dbolduc

google/cloud/bigtable/testing/mock_bigtable_stub.h

@@ -81,6 +81,40 @@ class MockBigtableStub : public bigtable_internal::BigtableStub {
       (override));
 };
 
+class MockMutateRowsStream : public google::cloud::internal::StreamingReadRpc<
+                                 google::bigtable::v2::MutateRowsResponse> {
+ public:
+  MOCK_METHOD(void, Cancel, (), (override));
+  using MutateRowsResultType =
+      absl::variant<Status, google::bigtable::v2::MutateRowsResponse>;
+  MOCK_METHOD(MutateRowsResultType, Read, (), (override));
+  MOCK_METHOD(google::cloud::internal::StreamingRpcMetadata, GetRequestMetadata,
+              (), (const, override));
+};
+
+class MockReadRowsStream : public google::cloud::internal::StreamingReadRpc<
+                               google::bigtable::v2::ReadRowsResponse> {
+ public:
+  MOCK_METHOD(void, Cancel, (), (override));
+  using ReadRowsResultType =
+      absl::variant<Status, google::bigtable::v2::ReadRowsResponse>;
+  MOCK_METHOD(ReadRowsResultType, Read, (), (override));
+  MOCK_METHOD(google::cloud::internal::StreamingRpcMetadata, GetRequestMetadata,
+              (), (const, override));
+};
+
+class MockSampleRowKeysStream
+    : public google::cloud::internal::StreamingReadRpc<
+          google::bigtable::v2::SampleRowKeysResponse> {
+ public:
+  MOCK_METHOD(void, Cancel, (), (override));
+  using SampleRowKeysResultType =
+      absl::variant<Status, google::bigtable::v2::SampleRowKeysResponse>;
+  MOCK_METHOD(SampleRowKeysResultType, Read, (), (override));
+  MOCK_METHOD(google::cloud::internal::StreamingRpcMetadata, GetRequestMetadata,
+              (), (const, override));
+};
+
 }  // namespace testing
 }  // namespace bigtable
 }  // namespace cloud