public void AllowChars_String() { // Arrange var filter = new CodePointFilter(); // Act var retVal = filter.AllowChars("\u0100\u0102"); // Assert Assert.Same(filter, retVal); // returns 'this' instance Assert.True(filter.IsCharacterAllowed('\u0100')); Assert.False(filter.IsCharacterAllowed('\u0101')); Assert.True(filter.IsCharacterAllowed('\u0102')); Assert.False(filter.IsCharacterAllowed('\u0103')); }