add tests for frontmatter parser

test/test_frontmatter.ml

@@ -1,3 +1,93 @@
 open Rechiko.Frontmatter
 
-(* TODO: add tests for extract_frontmatter & parse_frontmatter *)
+let simple_markdown =
+  {|
+---
+Title: "Test Document"
+Draft: true
+Date: "2023-10-01"
+---
+
+# Test Document
+
+This is a test document with frontmatter.
+|}
+
+let simple_markdown_yaml_section =
+  {|
+Title: "Test Document"
+Draft: true
+Date: "2023-10-01"
+  |}
+
+let simple_markdown_content =
+  {|
+# Test Document
+
+This is a test document with frontmatter.
+  |}
+
+let markdown_with_empty_frontmatter =
+  {|
+---
+---
+
+# Empty Frontmatter Document
+  |}
+
+let markdown_when_frontmatter_is_invalid_yaml =
+  {|
+---
+John: "Doe
+---
+
+" # bad yaml
+  |}
+
+let invalid_yaml_frontmatter = {|John: "Doe|}
+
+let%test "extract yaml from simplie markdown 1" =
+  let yaml_section, _ = extract_frontmatter simple_markdown in
+  String.trim yaml_section = String.trim simple_markdown_yaml_section
+
+let%test "extract content from simple markdown" =
+  let _, content = extract_frontmatter simple_markdown in
+  String.trim content = String.trim simple_markdown_content
+
+let%test "extract yaml from md with empty frontmatter" =
+  let yaml_section, _ = extract_frontmatter markdown_with_empty_frontmatter in
+  String.trim yaml_section = ""
+
+let%test "extract content from md with empty frontmatter" =
+  let _, content = extract_frontmatter markdown_with_empty_frontmatter in
+  String.trim content = "# Empty Frontmatter Document"
+
+let%test "extract yaml from md with invalid frontmatter" =
+  let yaml_section, _ =
+    extract_frontmatter markdown_when_frontmatter_is_invalid_yaml
+  in
+  String.trim yaml_section = invalid_yaml_frontmatter
+
+let%test "extract content from md with invalid frontmatter" =
+  let _, content =
+    extract_frontmatter markdown_when_frontmatter_is_invalid_yaml
+  in
+  String.trim content = {|" # bad yaml|}
+
+let%test "parse valid yaml" =
+  let fm = parse_frontmatter simple_markdown_yaml_section in
+  let expected =
+    StringMap.of_list
+      [
+        ("Title", `String "Test Document");
+        ("Draft", `Bool true);
+        ("Date", `String "2023-10-01");
+      ]
+  in
+  StringMap.equal Yojson.Safe.equal fm expected
+
+let%test "parse invalid yaml" =
+  try
+    ignore (parse_frontmatter invalid_yaml_frontmatter);
+    false
+  with Frontmatter_parse_error _ -> true