testACallbackCanBeSet
testTheCallbackWillBeExecuted
testMustBeATypeOfAction
testCanGeneratePHPCode
testWillUseDifferentCacheKeyEachTime
testItemCanBeFetchedBackFromCache
testTheCallbackWillNotBeExecutedIfNotCalled
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Must use Closure instead of callable
testOnErrorMustBeDefined
testOnIsAKeyword
testErrorIsAKeyword
testOnErrorCanBeAddedToTheEndOfAnAssertion
testOnErrorIsReturnedWhenLocatingTheMatcher
testOnErrorIsNotReturnedIfNotInTheSyntax
testOnErrorIsReturnedFromData
testOnErrorMustBeTheLastData
testCanSetCustomFailureMessage
testWillFailWithCustomMessage
testWillUseOnErrorMessage