Change test_makecpt.py to use colorbar instead of grdimage

[willschlitzer]

This modifies test_makecpt.py to use load_static_earth_relief.

Addresses #1684

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[github-actions]

Summary of changed images

This is an auto-generated report of images that have changed on the DVC remote

Status	Path
added	pygmt/tests/baseline/test_makecpt_plot_colorbar.png
added	pygmt/tests/baseline/test_makecpt_plot_colorbar_scaled_with_series.png
deleted	pygmt/tests/baseline/test_makecpt_plot_grid.png
deleted	pygmt/tests/baseline/test_makecpt_plot_grid_scaled_with_series.png
modified	pygmt/tests/baseline/test_makecpt_categorical.png
modified	pygmt/tests/baseline/test_makecpt_continuous.png
modified	pygmt/tests/baseline/test_makecpt_cyclic.png
modified	pygmt/tests/baseline/test_makecpt_plot_points.png
modified	pygmt/tests/baseline/test_makecpt_reverse_color_and_zsign.png
modified	pygmt/tests/baseline/test_makecpt_reverse_color_only.png
modified	pygmt/tests/baseline/test_makecpt_truncated_zlow_zhigh.png

Image diff(s)

Added images

• pygmt/tests/baseline/test_makecpt_plot_colorbar.png

• pygmt/tests/baseline/test_makecpt_plot_colorbar_scaled_with_series.png

Modified images

Path	Old	New
test_makecpt_categorical.png
test_makecpt_continuous.png
test_makecpt_cyclic.png
test_makecpt_plot_points.png
test_makecpt_reverse_color_and_zsign.png
test_makecpt_reverse_color_only.png
test_makecpt_truncated_zlow_zhigh.png

Report last updated at commit 6394922

[seisman]

In most tests, we call makecpt to create a CPT file and call grdimage to plot the earth relief grid. I feel it's very difficult to verify if the grid image is correct or not.

Why not just call colorbar to plot the color bar instead? It's more intuitive to see if the plotted color bar matches the makecpt command.

[seisman]

BTW, please change the PR title to "Change test_xxxx.py to use static_earth_relief".

[maxrjones]

Looks good after removing the region pytest fixture.

[maxrjones]

Looks good after removing the region pytest fixture.

Actually, I just noticed that this is used in test_makecpt_plot_points, but region does not need to be a fixture anymore because it is only used once. I recommend removing the fixture and just setting the region using a list in the region argument for plot.

[seisman]

@willschlitzer Still need to upload the new images to dvc, because names of these images have been changed in your last commit.

[maxrjones]

Thanks for updating these tests. I still would prefer if fixture_region() were removed and test_makecpt_plot_points() used a list as the argument type for region, but it is only a suggestion.

[weiji14]

Recommend modifying the PR title to say something like "Change test_makecpt.py to use colorbar instead of grdimage", since static_earth_relief isn't actually being used. Oh, and I second Meghan's suggestion to remove fixture_region if possible.

[seisman]

Looks good to me after this minor fix.

[weiji14]

Nice work!