Don't reformat classes if statement order unchanged

src/ssort/_ssort.py

@@ -229,7 +229,9 @@ def _key(statement):
 
 
 def _statement_text_sorted_class(statement):
-    head_text, statements = split_class(statement)
+    head_text, unsorted_statements = split_class(statement)
+
+    statements = list(unsorted_statements)
 
     # Take a snapshot of any hard dependencies between statements so that we can
     # restore them later.
@@ -317,6 +319,9 @@ def _statement_text_sorted_class(statement):
         sorted_statements, graph=runtime_graph
     )
 
+    if sorted_statements == unsorted_statements:
+        return statement.text
+
     return (
         head_text
         + "\n"

tests/test_ssort.py

@@ -678,3 +678,19 @@ def _notdep(self):
     )
     actual = ssort(original)
     assert actual == expected
+
+
+def test_single_line_dummy_function():
+    original = "def fun(): ...\n"
+    expected = "def fun(): ...\n"
+
+    actual = ssort(original)
+    assert actual == expected
+
+
+def test_single_line_dummy_class():
+    original = "class Class: ...\n"
+    expected = "class Class: ...\n"
+
+    actual = ssort(original)
+    assert actual == expected