rfc-conformity for cache validation

starlette/staticfiles.py

@@ -206,6 +206,8 @@ def is_not_modified(self, response_headers: Headers, request_headers: Headers) -
             etag = response_headers["etag"]
             if etag in [tag.strip(" W/") for tag in if_none_match.split(",")]:
                 return True
+            else:
+                return False
         except KeyError:
             pass
 

tests/test_staticfiles.py

@@ -230,6 +230,20 @@ def test_staticfiles_200_with_etag_mismatch(tmpdir: Path, test_client_factory: T
     assert second_resp.status_code == 200
     assert second_resp.content == b"<file content>"
 
+def test_staticfiles_200_with_etag_mismatch_and_timestamp_match(tmpdir: Path, test_client_factory: TestClientFactory) -> None:
+    path = os.path.join(tmpdir, "example.txt")
+    with open(path, "w") as file:
+        file.write("<file content>")
+
+    app = StaticFiles(directory=tmpdir)
+    client = test_client_factory(app)
+    first_resp = client.get("/example.txt")
+    assert first_resp.status_code == 200
+    assert first_resp.headers["etag"] != '"123"'
+    last_modified = first_resp.headers["last-modified"]
+    second_resp = client.get("/example.txt", headers={"if-none-match": '"123"', "if-modified-since": last_modified})
+    assert second_resp.status_code == 200
+    assert second_resp.content == b"<file content>"
 
 def test_staticfiles_304_with_last_modified_compare_last_req(
     tmpdir: Path, test_client_factory: TestClientFactory