feat(csv-upload): Configurable max filesize (#24618)

tests/unit_tests/forms_tests.py

@@ -0,0 +1,54 @@
+import contextlib
+import tempfile
+from typing import Optional
+
+import pytest
+from flask_wtf.file import FileField
+from wtforms import Form, ValidationError
+
+from superset.forms import FileSizeLimit
+
+
+def _get_test_form(size_limit: Optional[int]) -> Form:
+    class TestForm(Form):
+        test = FileField("test", validators=[FileSizeLimit(size_limit)])
+
+    return TestForm()
+
+
+@contextlib.contextmanager
+def _tempfile(contents: bytes):
+    with tempfile.NamedTemporaryFile() as f:
+        f.write(contents)
+        f.flush()
+
+        yield f
+
+
+def test_file_size_limit_pass() -> None:
+    """Permit files which do not exceed the size limit"""
+    limit = 100
+    form = _get_test_form(limit)
+
+    with _tempfile(b"." * limit) as f:
+        form.test.data = f
+        assert form.validate() is True
+
+
+def test_file_size_limit_fail() -> None:
+    """Reject files which are too large"""
+    limit = 100
+    form = _get_test_form(limit)
+
+    with _tempfile(b"." * (limit + 1)) as f:
+        form.test.data = f
+        assert form.validate() is False
+
+
+def test_file_size_limit_ignored_if_none() -> None:
+    """Permit files when there is no limit"""
+    form = _get_test_form(None)
+
+    with _tempfile(b"." * 200) as f:
+        form.test.data = f
+        assert form.validate() is True