Add unit test coverage for PendingAuthListener. (#10806)

Part of #10566.

binder/src/test/java/io/grpc/binder/internal/PendingAuthListenerTest.java

@@ -0,0 +1,102 @@
+package io.grpc.binder.internal;
+
+import static com.google.common.truth.Truth.assertThat;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.verifyNoInteractions;
+import static org.mockito.Mockito.when;
+
+import org.junit.Before;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.JUnit4;
+import org.mockito.ArgumentCaptor;
+import org.mockito.Captor;
+import org.mockito.InOrder;
+import org.mockito.Mock;
+import org.mockito.Mockito;
+import org.mockito.junit.MockitoJUnit;
+import org.mockito.junit.MockitoRule;
+
+import io.grpc.Metadata;
+import io.grpc.ServerCall;
+import io.grpc.ServerCallHandler;
+import io.grpc.Status;
+
+@RunWith(JUnit4.class)
+public final class PendingAuthListenerTest {
+
+  @Rule public final MockitoRule mocks = MockitoJUnit.rule();
+
+  @Mock ServerCallHandler<Object, Object> next;
+  @Mock ServerCall<Object, Object> call;
+  @Mock ServerCall.Listener<Object> delegate;
+  @Captor ArgumentCaptor<Status> statusCaptor;
+
+  private final Metadata headers = new Metadata();
+  private final PendingAuthListener<Object, Object> listener = new PendingAuthListener<>();
+
+  @Before
+  public void setUp() {
+    when(next.startCall(call, headers)).thenReturn(delegate);
+  }
+
+  @Test
+  public void onCallbacks_noOpBeforeStartCall() {
+    listener.onReady();
+    listener.onMessage("foo");
+    listener.onHalfClose();
+    listener.onComplete();
+
+    verifyNoInteractions(delegate);
+  }
+
+  @Test
+  public void onCallbacks_runsPendingCallbacksAfterStartCall() {
+    String message = "foo";
+
+    // Act 1
+    listener.onReady();
+    listener.onMessage(message);
+    listener.startCall(call, headers, next);
+
+    // Assert 1
+    InOrder order = Mockito.inOrder(delegate);
+    order.verify(delegate).onReady();
+    order.verify(delegate).onMessage(message);
+
+    // Act 2
+    listener.onHalfClose();
+    listener.onComplete();
+
+    // Assert 2
+    order.verify(delegate).onHalfClose();
+    order.verify(delegate).onComplete();
+  }
+
+  @Test
+  public void onCallbacks_withCancellation_runsPendingCallbacksAfterStartCall() {
+    listener.onReady();
+    listener.onCancel();
+    listener.startCall(call, headers, next);
+
+    InOrder order = Mockito.inOrder(delegate);
+    order.verify(delegate).onReady();
+    order.verify(delegate).onCancel();
+  }
+
+  @Test
+  public void whenStartCallFails_closesTheCallWithInternalStatus() {
+    IllegalStateException exception = new IllegalStateException("oops");
+    when(next.startCall(any(), any())).thenThrow(exception);
+
+    listener.onReady();
+    listener.startCall(call, headers, next);
+
+    verify(call).close(statusCaptor.capture(), any());
+    Status status = statusCaptor.getValue();
+    assertThat(status.getCode()).isEqualTo(Status.Code.INTERNAL);
+    assertThat(status.getCause()).isSameInstanceAs(exception);
+  }
+}