private ScenarioDefinition(IReadOnlyList <TGiven> given, TWhen when, Exception expectedException, bool verifyMessage)
 {
     Given                  = given;
     When                   = when;
     Then                   = new TThen[] { };
     ExpectedException      = expectedException;
     VerifyExceptionMessage = verifyMessage;
 }
 private ScenarioDefinition(IReadOnlyList <TGiven> given, TWhen when, IReadOnlyList <TThen> then)
 {
     Given = given;
     When  = when;
     Then  = then;
 }