Like other programs, Internet Explorer has its tests to make sure that the new version of the browser behaves the same as the old one (unless the intention is otherwise). If a developer’s intervention breaks compatibility, tests ensure that they are aware of it. So no big program can be created without tests. The more tests there are, the better. The ideal is to cover each individual functionality. The W3 consortium therefore collects tests to which all browser manufacturers can contribute and use.
Microsoft did not use this option before. But the Internet Explorer product team has now decided to change that. It has thus gained the right to modify existing tests that contain bugs that occur only in Internet Explorer and thus have a deceptive effect on reducing the perception of its quality. The tricky thing is that the error is directly related to the way in which objects obtain their properties. It is not one test that fails, but thousands that use this method. Another treacherousness lies in the considerable simplification of work. Instead of focusing on the quality of support for the standard, the tests only test an attempt to support it. They only examine the presence of the object’s property and do not care whether changing it does what the standard describes. Therefore, the current W3C tests will not prove the quality of the implementation of standards in Internet Explorer. Therefore, it became disadvantageous to stand outside.
Microsoft is moving its 150,000 tests to the W3C. Some of them can be found on the popular GitHub. After this step, there was criticism that Internet Explorer passes all Microsoft tests. Yes, it is really so. That’s why the tests were written. At the same time, the IE Testing Center is being closed.