fix files external test run and add common-tests option

apps/files_external/tests/README.md

@@ -42,6 +42,11 @@ then runs the unit test suite from `backends/webdav.php` (because the middle par
 the name of the script is `webdav`) and finally tries to call
 `stop-webdav-ownCloud.sh` for cleanup purposes.
 
+If `common-tests` is supplied as second argument it will skip the backend specific
+part completely and just run the common files_external unit tests:
+
+    ./autotest-external.sh sqlite common-tests
+
 ## The more manual way of unit test execution
 
 If you want to debug your external storage provider, you maybe don't want to

autotest-external.sh

@@ -24,6 +24,7 @@ function print_syntax {
 	echo -e "\nExample: ./autotest.sh sqlite webdav-ownCloud" >&2
 	echo "will run the external suite from \"apps/files_external/tests/env/start-webdav-ownCloud.sh\"" >&2
 	echo -e "\nIf no arguments are specified, all available external backends will be run with all database configs" >&2
+	echo -e "\nIf you specify 'common-tests' as startfile it will just run the tests that are independent from the backends" >&2
 }
 
 if ! [ -x "$PHPUNIT" ]; then
@@ -219,14 +220,18 @@ EOF
 	# just enable files_external
 	php ../occ app:enable files_external
 	if [ -z "$NOCOVERAGE" ]; then
-		#"$PHPUNIT" --configuration phpunit-autotest-external.xml --log-junit "autotest-external-results-$1.xml" --coverage-clover "autotest-external-clover-$1.xml" --coverage-html "coverage-external-html-$1"
+		"$PHPUNIT" --configuration phpunit-autotest-external.xml --log-junit "autotest-external-results-$1.xml" --coverage-clover "autotest-external-clover-$1.xml" --coverage-html "coverage-external-html-$1"
 		RESULT=$?
 	else
 		echo "No coverage"
-		#"$PHPUNIT" --configuration phpunit-autotest-external.xml --log-junit "autotest-external-results-$1.xml"
+		"$PHPUNIT" --configuration phpunit-autotest-external.xml --log-junit "autotest-external-results-$1.xml"
 		RESULT=$?
 	fi
 
+	if [ -n "$2" -a "$2" == "common-tests" ]; then
+	    return;
+	fi
+
     FILES_EXTERNAL_BACKEND_PATH=../apps/files_external/tests/backends
     FILES_EXTERNAL_BACKEND_ENV_PATH=../apps/files_external/tests/env