+1 this issue. I have encountered this problem lots when testing patches and almost always just end up deleting the test_from method to get test_tk to pass. I am not sure of a solution, though, as we *need* to keep test compatibility with Tk 8.6.8 while (preferably) being able to recognise when the value is wrong for the given version. I hope to take a more in-depth look at the problem and possible solutions (I want to avoid, if possible, either checking the Tk version or allowing both 14.9 & 15.0 values to pass the test).