Test that the Sage git repo is clean.

Author: jhpalmieri

src/sage/tests/git.py

@@ -0,0 +1,10 @@
+"""
+Test that the Sage git repo is clean.
+
+sage: from sage.features import Executable
+sage: from sage.tests.cmdline import test_executable
+sage: if Executable(name='git', executable='git').is_present():
+....:     (out, err, ret) = test_executable(["git", "status", "--porcelain"])
+....:     if len(out) > 0:
+....:         raise OSError('Git repo is not clean')
+"""