Check stepMismatch results for type=datetime. On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE". Empty values PASS stepMismatchFor("", null, null) is false PASS stepMismatchFor("", "2", "1969-12-31T12:34:56Z") is false Normal step values PASS stepMismatchFor("2010-02-09T12:34:55Z", "1", "2010-02-09T12:34:56Z") is false PASS stepMismatchFor("2010-02-09T12:34:55.001Z", "1", "2010-02-09T12:34:56Z") is true PASS stepMismatchFor("2010-02-09T12:34:56.001Z", "0.001", "2010-02-09T12:34:56Z") is false PASS stepMismatchFor("2010-02-09T12:34:55Z", "0.333", "2010-02-09T12:34:56Z") is true PASS stepMismatchFor("2010-02-09T12:34:55.001Z", "0.333", "2010-02-09T12:34:56Z") is false PASS stepMismatchFor("2010-02-09T12:34Z", "86400", "2010-02-08T12:34Z") is false PASS stepMismatchFor("2010-02-09T12:34:56Z", "86400", "2010-02-08T12:34Z") is true PASS stepMismatchFor("275760-09-13T00:00Z", "3", "275760-09-12T23:59:50Z") is true PASS stepMismatchFor("275760-09-13T00:00Z", "2", "275760-09-12T23:59:50Z") is false PASS stepMismatchFor("0001-01-01T00:00Z", "3", "0001-01-11T00:00:02Z") is true PASS stepMismatchFor("0001-01-01T00:00Z", "2", "0001-01-11T00:00:02Z") is false Implicit step base PASS stepMismatchFor("1970-01-01T12:34Z", "120", null) is false PASS stepMismatchFor("1970-01-01T12:35Z", "120", null) is true Small step values PASS stepMismatchFor("2010-02-10T12:34:56.000Z", "0.0003", "2010-02-10T12:34.55.000Z") is false PASS stepMismatchFor("2010-02-10T12:34:55.001Z", "0.0019", "2010-02-10T12:34.55.000Z") is true Invalid or no step values PASS stepMismatchFor("2010-02-10T12:34Z", null, "2010-02-09T12:34Z") is false PASS stepMismatchFor("2010-02-10T12:34:56Z", null, "2010-02-09T12:34Z") is true PASS stepMismatchFor("2010-02-10T12:34Z", "-1", "2010-02-09T12:34Z") is false PASS stepMismatchFor("2010-02-10T12:34Z", "foo", "2010-02-09T12:34Z") is false Special step value PASS stepMismatchFor("2010-02-09T12:34Z", "any", "2010-02-09T12:34Z") is false Disabled PASS stepMismatchFor("2010-02-09T12:34:55.001Z", "1", "2010-02-09T12:34:56Z", true) is false PASS successfullyParsed is true TEST COMPLETE