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.