refactor: rewrite from Ruby/Sinatra to Python/FastAPI

tests/test_frontmatter.py

@@ -0,0 +1,78 @@
+"""Tests for Frontmatter parser — TOML frontmatter parsing and serialisation."""
+
+from __future__ import annotations
+
+from volumen.frontmatter import dump, parse
+
+
+class TestParse:
+    def test_parse_extracts_metadata_and_body(self) -> None:
+        content = '+++\ntitle = "Hello"\ntags = ["a", "b"]\n+++\n\nBody text.\n'
+        metadata, body = parse(content)
+        assert metadata["title"] == "Hello"
+        assert metadata["tags"] == ["a", "b"]
+        assert body == "Body text.\n"
+
+    def test_parse_without_frontmatter(self) -> None:
+        metadata, body = parse("# Just markdown\n")
+        assert metadata == {}
+        assert body == "# Just markdown\n"
+
+    def test_parse_without_closing_delimiter(self) -> None:
+        content = '+++\ntitle = "x"\n\nbody'
+        metadata, body = parse(content)
+        assert metadata == {}
+        assert body == content
+
+    def test_parse_empty_frontmatter(self) -> None:
+        content = "+++\n+++\n\nBody here.\n"
+        metadata, body = parse(content)
+        assert metadata == {}
+        assert body == "Body here.\n"
+
+    def test_parse_draft_false(self) -> None:
+        content = '+++\ntitle = "X"\ndraft = false\n+++\n\nBody\n'
+        metadata, body = parse(content)
+        assert metadata["draft"] is False
+
+    def test_parse_nested_tables(self) -> None:
+        content = '+++\n[meta]\ntitle = "X"\n+++\n\nBody\n'
+        metadata, body = parse(content)
+        assert metadata["meta"]["title"] == "X"
+
+    def test_parse_normalises_crlf(self) -> None:
+        metadata, body = parse('+++\r\ntitle = "x"\r\n+++\r\n\r\nBody\r\n')
+        assert metadata["title"] == "x"
+        assert body == "Body\n"
+
+
+class TestDump:
+    def test_dump_produces_valid_frontmatter(self) -> None:
+        result = dump({"title": "Hello", "tags": ["a"]}, "Body text.\n")
+        assert result.startswith("+++\n")
+        assert "+++\n\n" in result
+        assert "Body text." in result
+
+    def test_dump_empty_metadata(self) -> None:
+        result = dump({}, "Just body.\n")
+        assert "+++" in result
+        assert "Just body." in result
+
+    def test_round_trip(self) -> None:
+        metadata = {"title": "Hello", "tags": ["intro"], "draft": False}
+        dumped = dump(metadata, "Hello **world**.")
+        parsed_meta, parsed_body = parse(dumped)
+        assert parsed_meta == metadata
+        assert parsed_body.strip() == "Hello **world**."
+
+    def test_round_trip_with_empty_metadata(self) -> None:
+        dumped = dump({}, "Just body.\n")
+        parsed_meta, parsed_body = parse(dumped)
+        assert parsed_meta == {}
+        assert parsed_body.strip() == "Just body."
+
+    def test_round_trip_preserves_dates(self) -> None:
+        metadata = {"title": "X", "date": "2026-01-15"}
+        dumped = dump(metadata, "Body\n")
+        parsed_meta, _ = parse(dumped)
+        assert parsed_meta["date"] == "2026-01-15"