Fix parsing of Polygon statement metadata

polygon_cli/problem.py

@@ -307,6 +307,13 @@ def get_statements_list(self):
         for lang, files_raw in statements_raw.items():
             encoding = files_raw.get('encoding', None)
             for name, content in files_raw.items():
+                # The API response also contains statement metadata. In
+                # particular, `encoding` is a string and newer Polygon
+                # versions include boolean review flags. None of those fields
+                # represent downloadable statement sections.
+                if name == 'encoding' or not isinstance(content, str):
+                    continue
+
                 file = polygon_file.PolygonFile()
                 file.type = 'statement'
                 file.name = '%s/%s.tex' % (lang, name)

tests/test_problem.py

@@ -0,0 +1,59 @@
+import unittest
+
+from polygon_cli.problem import ProblemSession
+
+
+class GetStatementsListTest(unittest.TestCase):
+    def setUp(self):
+        self.session = ProblemSession('main', 123, None, verbose=False)
+
+    def test_ignores_encoding_and_boolean_metadata(self):
+        response = {
+            'english': {
+                'name': 'Example',
+                'legend': 'Solve it.',
+                'input': 'An integer.',
+                'output': 'Its answer.',
+                'notes': '',
+                'tutorial': 'Use math.',
+                'encoding': 'UTF-8',
+                'showCautionsAndGrammaticalFixes': False,
+                'showInReview': True,
+            },
+        }
+        self.session.send_api_request = lambda *_args, **_kwargs: response
+
+        files = self.session.get_statements_list()
+
+        self.assertEqual(
+            [file.name for file in files],
+            [
+                'english/name.tex',
+                'english/legend.tex',
+                'english/input.tex',
+                'english/output.tex',
+                'english/notes.tex',
+                'english/tutorial.tex',
+            ],
+        )
+        self.assertEqual(files[0].content, b'Example')
+        self.assertTrue(all(file.type == 'statement' for file in files))
+
+    def test_uses_the_language_encoding_for_statement_content(self):
+        response = {
+            'spanish': {
+                'name': 'Números ocultos',
+                'encoding': 'iso-8859-1',
+            },
+        }
+        self.session.send_api_request = lambda *_args, **_kwargs: response
+
+        files = self.session.get_statements_list()
+
+        self.assertEqual(len(files), 1)
+        self.assertEqual(files[0].name, 'spanish/name.tex')
+        self.assertEqual(files[0].content, 'Números ocultos'.encode('iso-8859-1'))
+
+
+if __name__ == '__main__':
+    unittest.main()