gistfile1.swift

public enum QueryResult {
    case Success(ResultSet)
  case Failure(SQLError)
}

func ==(a:QueryResult, b:QueryResult) -> Bool {
  switch(a) {
  case .Success(_):
    switch (b) {
    case .Success(_): return true
    case .Failure(_): return false
    }
  case .Failure(_):
    switch (b) {
    case .Success(_): return false
    case .Failure(_): return true
    }
  default: return false
  }
}

func testSelect() {
  var queryResult:QueryResult = self.database.executeQuery("SELECT * FROM PERSON", arguments:[])
  XCTAssertTrue(queryResult == QueryResult.Success)
}

// Yields: Could not find an overload for '==' that accepts the supplied arguments