Add test for fixing standalone bracket line blocks in test.py; enhance regex in EquationFixer to handle new block format

Author: dynstat

src/markdown_equations_fixer/cli.py

@@ -33,6 +33,21 @@ def __init__(self, dry_run: bool = False, verbose: bool = False):
     def fix_equations(self, content: str) -> str:
         """Fix mathematical equations in markdown content."""
         try:
+            # Pattern to match block equations delimited by standalone lines with [ and ]
+            # Example:
+            # [\n
+            # equation content\n
+            # ]
+            # This converts to:
+            # $$\n
+            # equation content\n
+            # $$
+            content = re.sub(
+                r"(?ms)^\[\s*$\n(.*?)\n^\]\s*$",
+                r"$$\n\1\n$$",
+                content,
+            )
+
             # Pattern to match block equations: \[ ... \]
             # The re.DOTALL flag allows the match to span multiple lines.
             content = re.sub(

src/test.py

@@ -42,6 +42,13 @@ def test_fix_inline_equations(fixer):
     )
 
 
+def test_fix_bracket_line_block(fixer):
+    """Test fixing blocks where [ and ] are on their own lines."""
+    input_text = "[\nE=mc^2\n]"
+    expected = "$$\nE=mc^2\n$$"
+    assert fixer.fix_equations(input_text) == expected
+
+
 def test_validate_paths_recursive(temp_dir):
     """Test recursive path validation."""
     paths = [temp_dir]