Merge pull request #119 from asottile/raise_on_no_input_directory

Error when source directory does not exist.  Resolves #116.

Author: asottile

sass.py

@@ -195,12 +195,16 @@ def _to_importer(priority, func):
     return tuple(_to_importer(priority, func) for priority, func in importers)
 
 
+def _raise(e):
+    raise e
+
+
 def compile_dirname(
     search_path, output_path, output_style, source_comments, include_paths,
     precision, custom_functions, importers
 ):
     fs_encoding = sys.getfilesystemencoding() or sys.getdefaultencoding()
-    for dirpath, _, filenames in os.walk(search_path):
+    for dirpath, _, filenames in os.walk(search_path, onerror=_raise):
         filenames = [
             filename for filename in filenames
             if filename.endswith(('.scss', '.sass')) and

sasstests.py

@@ -847,6 +847,10 @@ def write_file(filename, contents):
 
 class CompileDirectoriesTest(unittest.TestCase):
 
+    def test_directory_does_not_exist(self):
+        with pytest.raises(OSError):
+            sass.compile(dirname=('i_dont_exist_lol', 'out'))
+
     def test_successful(self):
         with tempdir() as tmpdir:
             input_dir = os.path.join(tmpdir, 'input')