public void FormatSpecialCharacters_StringWasCorrectlyFormattedToStringWithoutSpecialCharacters() { ArrayFormat arrayFormat = new ArrayFormat(); string fileName = System.IO.Directory.GetCurrentDirectory().Replace(@"ExerciseOrderBy.Tests\bin\Debug", @"\ExerciseOrderBy\input.txt"); string lowerText = System.IO.File.ReadAllText(fileName).ToLower(); string text = arrayFormat.FormatSpecialCharacters(lowerText); var regexItem = new Regex("^[a-zA-Z0-9 ]*$"); Assert.IsTrue(regexItem.IsMatch(text), "Formatted message contains at least one special character"); }