assertThat(e).hasMessageThat().isEqualTo("A null C");
  }

  @J2ktIncompatible // TODO(b/319404022): Allow passing null array as varargs
  public void testCheckArgument_singleNullArray_failure() {
    IllegalArgumentException e =
        assertThrows(
            IllegalArgumentException.class, () -> checkArgument(false, "A %s C", (Object[]) null));