public IEnumerable<TestCaseData> Should_ReturnRightSubject_WhenCalledGetSubject_TestCaseSource()
{
yield return new TestCaseData("Fwd: Test subject");
yield return new TestCaseData("Fw: Test subject");
yield return new TestCaseData("fwd: Test subject");
yield return new TestCaseData("fw: Test subject");
yield return new TestCaseData("Test subject");
}