public String get(String key) {
    Supplier<String> supplier = evaluatedEntries.get(key);
    return supplier != null
        ? supplier.get()
        : null;
  }
@Test
  public void testNullValue() throws Throwable {
    assertThat(context.get(PARAM_PROCESS))
        .describedAs("Value of context element %s", PARAM_PROCESS)
        .isNull();
  }