Keep csv parity tests aligned with QUOTE_NONE support

doma17 · doma17 · commit 9723fff32d94 · 2026-06-30T23:14:44.000+09:00
Remove the stale RustPython expected-failure marker for the CPython escaped-field writer test that now passes, and cover CR/LF escaping in the snippet regression requested during review.

Constraint: RustPython test policy allows removing expectedFailure markers only when the upstream test passes.

Rejected: Refactoring writer row boilerplate in this follow-up | review marked it as a heavy-lift nitpick and it would broaden the CI fix.

Confidence: high

Scope-risk: narrow

Tested: cargo run --release --features sqlite -- -m test test_csv; cargo run -- extra_tests/snippets/stdlib_csv.py; PATH=/tmp/pyshim:$PATH prek run --all-files; git diff --check; cargo test --workspace --exclude rustpython_wasm --exclude rustpython-venvlauncher; pytest -v in extra_tests

Assisted-by: Codex:gpt-5.5
diff --git a/Lib/test/test_csv.py b/Lib/test/test_csv.py
@@ -854,7 +854,6 @@ class EscapedExcel(csv.excel):
 class TestEscapedExcel(TestCsvBase):
     dialect = EscapedExcel()
 
-    @unittest.expectedFailure  # TODO: RUSTPYTHON
     def test_escape_fieldsep(self):
         self.writerAssertEqual([['abc,def']], 'abc\\,def\r\n')
 
diff --git a/extra_tests/snippets/stdlib_csv.py b/extra_tests/snippets/stdlib_csv.py
@@ -101,6 +101,15 @@ def test_quote_none_writer_without_quotechar():
     ).writerow(["a\\b"])
     assert escapechar_buf.getvalue() == "a\\\\b\r\n"
 
+    linebreak_buf = io.StringIO()
+    csv.writer(
+        linebreak_buf,
+        quoting=csv.QUOTE_NONE,
+        quotechar=None,
+        escapechar="\\",
+    ).writerow(["a\rb", "c\nd"])
+    assert linebreak_buf.getvalue() == "a\\\rb,c\\\nd\r\n"
+
     with assert_raises(csv.Error):
         csv.writer(io.StringIO(), quoting=csv.QUOTE_NONE, quotechar=None).writerow(
             ["a,b"]
