String toTest =
        MoreObjects.toStringHelper(new TestClass()).add("field1", (Integer) null).toString();
    assertThat(toTest).isEqualTo("TestClass{field1=null}");
  }

  public void testToStringLenient_oneField() {
    String toTest = MoreObjects.toStringHelper(new TestClass()).add("field1", "Hello").toString();
    assertTrue(toTest, toTest.matches(".*\\{field1\\=Hello\\}"));
  }