assume().that(graph.allowsSelfLoops()).isFalse();

    IllegalArgumentException e =
        assertThrows(IllegalArgumentException.class, () -> putEdge(N1, N1));
    assertThat(e).hasMessageThat().contains(ERROR_SELF_LOOP);
  }

  @Test
  public void putEdge_allowsSelfLoops() {
    assume().that(graphIsMutable()).isTrue();
    assume().that(graph.allowsSelfLoops()).isTrue();

    assume().that(graph.allowsSelfLoops()).isFalse();

    IllegalArgumentException e =
        assertThrows(IllegalArgumentException.class, () -> putEdge(N1, N1));
    assertThat(e).hasMessageThat().contains(ERROR_SELF_LOOP);
  }

  @Test
  public void putEdge_allowsSelfLoops() {
    assume().that(graphIsMutable()).isTrue();
    assume().that(graph.allowsSelfLoops()).isTrue();

    IllegalArgumentException e =
        assertThrows(IllegalArgumentException.class, () -> graphAsMutableGraph.putEdge(N1, N1));
    assertThat(e).hasMessageThat().contains(ERROR_SELF_LOOP);
  }

  @Test
  public void putEdge_allowsSelfLoops() {
    assume().that(graphIsMutable()).isTrue();
    assume().that(graph.allowsSelfLoops()).isTrue();

      "Collection returned is unexpectedly modifiable";
  static final String ERROR_SELF_LOOP = "self-loops are not allowed";
  static final String ERROR_EDGE_NOT_IN_GRAPH =
      "Should not be allowed to pass an edge that is not an element of the graph.";
  static final String ERROR_ADDED_SELF_LOOP = "Should not be allowed to add a self-loop edge.";
  static final String ERROR_ADDED_PARALLEL_EDGE = "Should not be allowed to add a parallel edge.";

      "Collection returned is unexpectedly modifiable";
  static final String ERROR_SELF_LOOP = "self-loops are not allowed";
  static final String ERROR_EDGE_NOT_IN_GRAPH =
      "Should not be allowed to pass an edge that is not an element of the graph.";
  static final String ERROR_ADDED_SELF_LOOP = "Should not be allowed to add a self-loop edge.";
  static final String ERROR_ADDED_PARALLEL_EDGE = "Should not be allowed to add a parallel edge.";

        "//tensorflow/core:protos_all_cc",
        "//tensorflow/core:test",
        "//tensorflow/core:test_main",
    ],
)

tf_cc_test(
    name = "while_loop_test",
    size = "medium",
    srcs = ["while_loop_test.cc"],
    deps = [
        ":c_api",
        ":c_test_util",
        "//tensorflow/core:lib",
        "//tensorflow/core:test",
        "//tensorflow/core:test_main",

    IllegalArgumentException e =
        assertThrows(
            IllegalArgumentException.class, () -> networkAsMutableNetwork.addEdge(N1, N1, E11));
    assertThat(e).hasMessageThat().contains(ERROR_SELF_LOOP);
  }

  /**
   * This test checks an implementation dependent feature. It tests that the method {@code addEdge}
   * will silently add the missing nodes to the graph, then add the edge connecting them. We are not

    IllegalArgumentException e =
        assertThrows(
            IllegalArgumentException.class, () -> networkAsMutableNetwork.addEdge(N1, N1, E11));
    assertThat(e).hasMessageThat().contains(ERROR_SELF_LOOP);
  }

  /**
   * This test checks an implementation dependent feature. It tests that the method {@code addEdge}
   * will silently add the missing nodes to the graph, then add the edge connecting them. We are not

    SomeChainingException exception = new SomeChainingException(new SomeChainingException(cause));
    assertSame(cause, Throwables.getRootCause(exception));
  }

  public void testGetRootCause_Loop() {
    Exception cause = new Exception();
    Exception exception = new Exception(cause);
    cause.initCause(exception);
    try {
      Throwables.getRootCause(cause);
      fail("Should have throw IAE");

    SomeChainingException exception = new SomeChainingException(new SomeChainingException(cause));
    assertSame(cause, Throwables.getRootCause(exception));
  }

  public void testGetRootCause_Loop() {
    Exception cause = new Exception();
    Exception exception = new Exception(cause);
    cause.initCause(exception);
    try {
      Throwables.getRootCause(cause);
      fail("Should have throw IAE");