TST: Configure test collection per sphinx availability

When sphinx is not installed, ignore the numpydoc.py and
docscrape_sphinx.py modules during test collection as they
depend on sphinx.

Author: rossbar

conftest.py

@@ -0,0 +1,15 @@
+# Configure test collection to skip doctests for modules that depend on sphinx
+# when sphinx is not available in the environment.
+
+try:
+    import sphinx
+
+    has_sphinx = True
+except ImportError:
+    has_sphinx = False
+
+
+collect_ignore = []
+
+if not has_sphinx:
+    collect_ignore += ["numpydoc/numpydoc.py", "numpydoc/docscrape_sphinx.py"]