add test cases for git/annexed conversions

Make sure that tip keeps working.

I tried to go futher and touch the file and make sure it stayed what it
was converted to, but struggled with some weird and not entirely
reproducable behavior, so kept the tests simple for now.

Test/Framework.hs

@@ -415,6 +415,16 @@ annexed_notpresent_imported f = ifM (annexeval Config.crippledFileSystem)
 unannexed :: FilePath -> Assertion
 unannexed = runchecks [checkregularfile, checkcontent, checkwritable]
 
+-- Check that a file is unannexed, but also that what's recorded in git
+-- is not an annexed file.
+unannexed_in_git :: FilePath -> Assertion
+unannexed_in_git f = do
+	unannexed f
+	r <- annexeval $ Annex.WorkTree.lookupKey (toRawFilePath f)
+	case r of
+		Just _k -> assertFailure $ f ++ " is annexed in git"
+		Nothing -> return ()
+
 add_annex :: FilePath -> String -> Assertion
 add_annex f faildesc = ifM (unlockedFiles <$> getTestMode)
 	( git "add" [f] faildesc