StringWithoutSubstringTest.testStringNonEmptyWithNullSubstringFail: String 'referenceA'(okay) does NOT have substring(null). StringWithoutSubstringTest.testStringNullWithNullSubstringFail: String 'referenceA'(null) does NOT have substring(null). StringWithoutSubstringTest.testStringEmptyWithNullSubstringFail: String 'referenceA'() does NOT have substring(null). StringWithoutSubstringTest.testStringNullWithEmptySubstringFail: String 'referenceA'(null) does NOT have substring(). StringWithoutSubstringTest.testStringNonEmptyWithNonMatchingSubstringFailMessage: String 'referenceA'(okay) does NOT have substring(xyz). addition info.