@Test
public void getExpireAfter_returnsNullIfHeaderNotPresent(TestContext testContext) {

    // Mock
    final String headerValue = null;
    final MultiMap headers = createHeaderReturningSimpleValue(HTTP_HEADER_X_EXPIRE_AFTER, headerValue);
    // Trigger work
    final Integer returnedExpireValue = ExpiryCheckHandler.getExpireAfter(headers);
    // Assert
    testContext.assertNull(returnedExpireValue);
}