Personal tex compilation fixes

tests/test_statement_resume.py

@@ -151,6 +151,33 @@ class FullStatementResumeTests(unittest.TestCase):
                 response(contexts=[]),
                 response(rubrics=[{'label': 'Ex 1', 'rubric_content': '4 points : correct'}])]
 
+    def test_compile_only_never_enters_analysis_and_preserves_sources(self):
+        directory = self.root / 'Sol2'
+        directory.mkdir()
+        tex = directory / '1.tex'
+        tex.write_text('manually edited solution')
+        with patch.object(gemini, 'process_exam') as analysis, patch.object(
+                gemini, 'compile_to_pdf', self.compiler):
+            self.assertEqual(gemini.main([str(self.root), '--compile-only']), 0)
+        analysis.assert_not_called()
+        self.assertEqual(tex.read_text(), 'manually edited solution')
+        self.assertEqual((directory / '1.pdf').read_bytes(), b'PDF')
+        self.assertEqual(self.compiler.call_args.kwargs['source_path'], self.root / 'correction.tex')
+
+    def test_preamble_change_recompiles_previously_successful_pdfs(self):
+        self.client.models.generate_content.side_effect = self.responses()
+        self.assertEqual(self.run_exam(), ExitCode.SUCCESS)
+        self.compiler.reset_mock()
+        self.assertEqual(self.run_exam(), ExitCode.SUCCESS)
+        self.compiler.assert_not_called()
+        (self.root / 'correction.tex').write_text(
+            r'\documentclass{article}\newcommand{\custom}{new}\begin{document}')
+        self.client.models.generate_content.reset_mock()
+        self.assertEqual(self.run_exam(), ExitCode.SUCCESS)
+        self.client.models.generate_content.assert_not_called()
+        self.assertEqual(self.compiler.call_count, 1)
+        self.assertEqual(self.compiler.call_args.args[1], self.root / 'Sol2/Ex 1.pdf')
+
     def test_rubric_failure_retry_keeps_grouping_edits_and_sources(self):
         self.client.models.generate_content.side_effect = [*self.responses()[:3], RuntimeError('offline')]
         self.assertEqual(self.run_exam(), ExitCode.PARTIAL)