tests: skip doctests if not running from a hg repo

Differential Revision: https://phab.mercurial-scm.org/D9150

tests/test-doctest.py

@@ -4,7 +4,7 b' from __future__ import absolute_import'
 from __future__ import print_function
 
 import doctest
-import os
+import os.path
 import re
 import subprocess
 import sys
@@ -72,6 +72,9 b" fileset = 'set:(**.py)'"
 
 cwd = os.path.dirname(os.environ["TESTDIR"])
 
+if not os.path.isdir(os.path.join(cwd, ".hg")):
+    sys.exit(0)
+
 files = subprocess.check_output(
     "hg files --print0 \"%s\"" % fileset, shell=True, cwd=cwd,
 ).split(b'\0')