public void TextObjectSetPropertyTest() { const string source = "abc=123; def=789"; var textObject = new TextObject(source); // replace the first occurrence of = followed by a number of digits Assert.IsTrue(textObject.SetProperty("(?:=(\\d+))", "456")); Assert.AreEqual("abc=456; def=789", textObject.Serialize()); // regex should not match, so it should not change anything Assert.IsFalse(textObject.SetProperty("(?:ghi=(\\d+))", "456")); Assert.AreEqual("abc=456; def=789", textObject.Serialize()); }