visual testing needs an update (and maybe some regressions?)

[1ucian0]

Currently (0.24.0.dev0+126c9ba), the images in the visual testing are falling behind. Some, they might even highlight regressions. Here a list of the suspicious ones:

• test_idle_wires_barrier: maybe the default changed? reference new image diff
• test_plot_barriers: the barrier label is great reference new image diff
• test_plot_state_hinton: why smaller? reference new image diff
• test_plot_histogram_2_sets_with_rest (histogram_2_sets_with_rest.png): the result is not the same reference new image diff

Run jupyter notebook test/ipynb/mpl_tester.ipynb to check details

This issue is to update the reference images and submit issues for regressions when confirmed

[jakelishman]

All of these look familiar to me as changes made within the last year, but I don't remember exactly the PRs. For test_plot_barriers: I had a look briefly at that test, and the "barrier" with a label is actually an ancient Snapshot instruction, so it probably changed when the handling around barrier labels changed.

The Hinton one is smaller because it needs to be for a bugfix #8847. The plot histogram change was deliberate in #7481 or something, though I remain unconvinced that number_to_keep can have a sensible meaning when you're plotting multiple datasets.

[1ucian0]

So, none of these are regressions?

test_plot_barriers seems to me that it should have the snapshot name on top.

[jakelishman]

Yeah, that one I'm not sure about, but the others are all deliberate changes I believe.

[enavarro51]

For test_idle_wires_barrier, the reference should be changed to match the new image.

For test_plot_barriers, when I run the tests locally, I get the reference displayed rather than your new image. The label should appear at the top of the barrier or snapshot if there is one.

Don't know about the other 2.

[1ucian0]

I think this is not valid anymore after #9961