public FileInputStream openInputStream(File file) {
    try {
      return openInputStreamOrThrowIOE(file);
    } catch (IOException e) {
      throw new IllegalStateException("Can not open file " + file, e);
    }
  }
@Test
  public void openInputStream_throws_ISE_if_file_does_not_exist() throws Exception {
    final File file = temp.newFile();
    assertThat(file.delete()).isTrue();

    assertThatThrownBy(() -> underTest.openInputStream(file))
      .isInstanceOf(IllegalStateException.class)
      .hasMessage("Can not open file " + file)
      .hasRootCauseMessage("File " + file + " does not exist");
  }