StateConverter { public static String getStateCode(String fullStateName) { if (states.isEmpty()) { putStates(); } return states.get(fullStateName); }  static String getStateCode(String fullStateName);  }
@Test public void testGetStateCode_returnsNullForNullKey() { assertThat(StateConverter.getStateCode(null)).isNull(); }
@Test public void testGetStateCode_returnsNullForNotFoundKey() { assertThat(StateConverter.getStateCode("This is not a state name")).isNull(); }
@Test public void testGetStateCode_returnsNYForNewYork() { assertThat(StateConverter.getStateCode("New York")).isEqualTo("NY"); }
@Test public void testGetStateCode_returnsNullForEmpty() { assertThat(StateConverter.getStateCode("")).isNull(); }
@Test public void testGetStateCode_returnsNullForBlank() { assertThat(StateConverter.getStateCode(" ")).isNull(); }