Move sphinx-gallery as an optional dependency for testing (#2439)

Author: seisman

.github/workflows/ci_doctests.yaml

@@ -64,7 +64,6 @@ jobs:
             pytest
             pytest-doctestplus
             pytest-mpl
-            sphinx-gallery
 
       # Download cached remote files (artifacts) from GitHub
       - name: Download remote data from GitHub

.github/workflows/ci_tests.yaml

@@ -72,6 +72,7 @@ jobs:
               geopandas
               ipython
               rioxarray
+              sphinx-gallery
 
     timeout-minutes: 30
     defaults:
@@ -123,7 +124,6 @@ jobs:
             pytest-cov
             pytest-doctestplus
             pytest-mpl
-            sphinx-gallery
 
       # Download cached remote files (artifacts) from GitHub
       - name: Download remote data from GitHub

.github/workflows/ci_tests_legacy.yaml

@@ -79,7 +79,6 @@ jobs:
             pytest
             pytest-doctestplus
             pytest-mpl
-            sphinx-gallery
 
       # Download cached remote files (artifacts) from GitHub
       - name: Download remote data from GitHub

pygmt/sphinx_gallery.py

@@ -2,7 +2,10 @@
 Utilities for using pygmt with sphinx-gallery.
 """
 
-import sphinx_gallery.scrapers
+try:
+    from sphinx_gallery.scrapers import figure_rst
+except ImportError:
+    figure_rst = None
 from pygmt.figure import SHOWED_FIGURES
 
 
@@ -29,4 +32,4 @@ def __call__(self, block, block_vars, gallery_conf):
             fig = figures.pop(0)
             fig.savefig(fname, transparent=True, dpi=200)
             image_names.append(fname)
-        return sphinx_gallery.scrapers.figure_rst(image_names, gallery_conf["src_dir"])
+        return figure_rst(image_names, gallery_conf["src_dir"])