tests/hghave.py

--- a/tests/hghave.py	Thu Feb 21 20:12:39 2019 -0500
+++ b/tests/hghave.py	Thu Feb 21 23:06:18 2019 -0500
@@ -822,3 +822,7 @@
     except (ImportError, AttributeError):
         pass
     return False
+
+@check('emacs', 'GNU Emacs')
+def has_emacs():
+    return matchoutput('emacs --version', b'GNU Emacs')