I spent a long time working on https://sourceforge.net/tracker/index.php?func=detail&aid=2861426&group_id=80706&atid=560720
and the associated unit test. I learned a lot and the unit tests really helped. First, I decided that if someone sets the formatter or locator to be a DateFormatter or DateLocator, then they are expressing their intention to plot dates, so I triggered the axis unit conversion pipeline on set_major_formatter(aDateFormatter) to use a DateConverter. This worked fine, but broke the JPL unit tests, because in their EpochConverter, they have a *different* class that nonetheless converts to the "datenum" floats, ie days since 0000-00-00, and thus they also use the AutoDateFormatter and AutoDateLocator in their AxisInfo converter info. So what was happening is that the unit tests for the Epochs passed in an Epoch instance, this triggered the unit conversion interface which set the formatter to be an AutoDateFormatter, which triggered my new code to use a DateConverter, which in turn broke the Epochs since the DateConverter doesn't know how to hand;e an Epoch. This is quite subtle, but what is happening is that two different classes are converting to the same floating point representation, and so both can use the same Formatter and Locator, but we can't invert -- just because we see a Formatter or Locator of a certain type, we can't infer the class. I would have never caught this w/o the unit test, would have happily committed my "fix" while screwing up all the JPL stuff. At the end of the day, after realizing all this, I decided the current behavior was not a bug at all, and that mpl was doing what it was told to do. And there is no way to be smart here, since the use of a DateFormatter does not imply you want a DateConverter. So I simply modified the DateFormatter code to raise with an intelligible message. The question is: what to do with the unit test I wrote to expose the : test_dates.test_empty_date_with_year_formatter I can either leave it as a knownfailure, since that is what it is, or modify it to set ax.xaxis_date as the traceback advises, and then add the image comparison. What do you think? Another win for the unit tests, though they caused me to spend a lot more time "fixing" this bug than I would have without them <wink> JDH ------------------------------------------------------------------------------ Come build with us! The BlackBerry® Developer Conference in SF, CA is the only developer event you need to attend this year. Jumpstart your developing skills, take BlackBerry mobile applications to market and stay ahead of the curve. Join us from November 9-12, 2009. Register now! http://p.sf.net/sfu/devconf _______________________________________________ Matplotlib-devel mailing list Matplotlib-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-devel
