Add some tests for sections and attribute access

Also switch to pytest only, since we're using fixtures.

Author: FichteFoll

tests/test_ass.py

@@ -1,15 +1,17 @@
 #!/usr/bin/env python
 
-import ass
-import unittest
+from io import StringIO
 from pathlib import Path
+from textwrap import dedent
 
-from io import StringIO
+import pytest
+
+import ass
 
 folder = Path(__file__).parent
 
 
-class TestEverything(unittest.TestCase):
+class TestDocument:
 
     test_ass = Path(folder, "test.ass")
 
@@ -25,11 +27,11 @@ def test_parse_dump(self):
 
     def test_parse_encoding(self):
         with self.test_ass.open("r", encoding='utf_8') as f:
-            with self.assertRaises(ValueError):
+            with pytest.raises(ValueError):
                 ass.parse(f)
 
         with self.test_ass.open("r", encoding='ascii') as f:
-            with self.assertRaises(ValueError):
+            with pytest.raises(ValueError):
                 ass.parse(f)
 
     def test_dump_encoding(self):
@@ -38,9 +40,79 @@ def test_dump_encoding(self):
 
         import tempfile
         with tempfile.TemporaryFile(mode='w', encoding='utf_8') as f:
-            with self.assertWarns(UserWarning):
+            with pytest.warns(UserWarning):
                 doc.dump_file(f)
 
 
-if __name__ == "__main__":
-    unittest.main()
+class TestSections:
+
+    def test_default_sections(self):
+        doc = ass.Document()
+        assert len(doc.sections) == 3
+        assert doc.fields is doc.info
+        assert len(doc.fields) == 0
+        assert len(doc.styles) == 0
+        assert len(doc.events) == 0
+
+    def test_scipt_info(self):
+        TEST_SCRIPT_INFO = dedent("""\
+            [Script Info]
+            ScriptType: v4.00+
+            PlayResX: 500
+            PlayResY: 500""")
+
+        doc = ass.Document.parse_string(TEST_SCRIPT_INFO)
+        doc.info["PlayResY"] = 50
+        doc.info["Arbitrary Field"] = "hi"
+
+        assert len(doc.sections) == 3
+        assert doc.info["PlayResX"] == 500
+        assert doc.play_res_y == 50
+        doc.play_res_y = 5
+        assert doc.play_res_y == 5
+
+        copy = doc.info.copy()
+        copy["PlayResX"] = 1
+        assert copy["Arbitrary Field"] == "hi"
+        assert doc.play_res_x == 500
+
+    def test_styles(self):
+        pass
+
+    def test_events(self):
+        pass
+
+    TEST_CUSTOM = dedent("""\
+        [Custom Section]
+        Line: 1
+        Line: 2
+        Line: 3
+        Another Line: 20""")
+
+    @pytest.fixture
+    def line_section(self):
+        doc = ass.Document.parse_string(self.TEST_CUSTOM)
+        return doc.sections["Custom Section"]
+
+    def test_custom_line_section_parse(self):
+        doc = ass.Document.parse_string(self.TEST_CUSTOM)
+        assert "custom section" in doc.sections
+        assert "Custom Section" in doc.sections
+        assert doc.sections["Custom Section"].name == "Custom Section"
+
+    def test_custom_line_section_read(self, line_section):
+        assert len(line_section) == 4
+        line = line_section[0]
+        assert isinstance(line, ass.Unknown)
+        assert line.TYPE == "Line"
+        assert line.value == "1"
+        assert line_section[-1].value == "20"
+
+    def test_custom_line_section_write(self, line_section):
+        line_section.add_line("Test", "test")
+        assert len(line_section) == 5
+        line_section[:3] = line_section[:2]  # remove 3rd line with a slice
+        assert [x.value for x in line_section] == ["1", "2", "20", "test"]
+
+    def test_custom_line_section_dump(self, line_section):
+        assert "\n".join(line_section.dump()) == self.TEST_CUSTOM