more tests

Change-Id: I1c45f2058cadc1acb9c6abd87222be9eb233778c

google-cloud-bigtable/src/test/java/com/google/cloud/bigtable/data/v2/stub/TransformingServerStreamingCallableTest.java

@@ -0,0 +1,74 @@
+/*
+ * Copyright 2024 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.
+ */
+package com.google.cloud.bigtable.data.v2.stub;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import com.google.cloud.bigtable.gaxx.testing.MockStreamingApi.MockResponseObserver;
+import com.google.cloud.bigtable.gaxx.testing.MockStreamingApi.MockServerStreamingCall;
+import com.google.cloud.bigtable.gaxx.testing.MockStreamingApi.MockServerStreamingCallable;
+import com.google.common.base.Functions;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.JUnit4;
+
+@RunWith(JUnit4.class)
+public class TransformingServerStreamingCallableTest {
+  @Test
+  public void testReqTransform() {
+    MockServerStreamingCallable<String, String> inner = new MockServerStreamingCallable<>();
+    TransformingServerStreamingCallable<Integer, String, String, String> xform =
+        new TransformingServerStreamingCallable<>(inner, Object::toString, Functions.identity());
+
+    MockResponseObserver<String> responseObserver = new MockResponseObserver<>(true);
+    xform.call(37, responseObserver);
+
+    MockServerStreamingCall<String, String> call = inner.popLastCall();
+    assertThat(call.getRequest()).isEqualTo("37");
+  }
+
+  @Test
+  public void testRespTransform() {
+    MockServerStreamingCallable<String, String> inner = new MockServerStreamingCallable<>();
+    TransformingServerStreamingCallable<String, Integer, String, String> xform =
+        new TransformingServerStreamingCallable<>(inner, Functions.identity(), Integer::parseInt);
+
+    MockResponseObserver<Integer> outerObserver = new MockResponseObserver<>(true);
+    xform.call("req", outerObserver);
+
+    MockServerStreamingCall<String, String> call = inner.popLastCall();
+    call.getController().getObserver().onResponse("37");
+
+    assertThat(outerObserver.popNextResponse()).isEqualTo(37);
+  }
+
+  @Test
+  public void testError() {
+    MockServerStreamingCallable<String, String> inner = new MockServerStreamingCallable<>();
+    TransformingServerStreamingCallable<String, String, String, String> xform =
+        new TransformingServerStreamingCallable<>(
+            inner, Functions.identity(), Functions.identity());
+
+    MockResponseObserver<String> outerObserver = new MockResponseObserver<>(true);
+    xform.call("req", outerObserver);
+
+    MockServerStreamingCall<String, String> call = inner.popLastCall();
+    RuntimeException e = new RuntimeException("fake error");
+    call.getController().getObserver().onError(e);
+
+    assertThat(outerObserver.getFinalError()).isEqualTo(e);
+  }
+}