fix: resolve CI test failure in output.py

- Fixed undefined 'tool' variable in display_history function
- Changed '[tool]' markup tag usage to proper Rich syntax
- All tests now pass (38/38 unit tests)
- Type checking passes with mypy --strict

tests/unit/test_markdown_formatter.py

@@ -0,0 +1,117 @@
+from codesnap.output.markdown_formatter import MarkdownFormatter
+
+
+class TestMarkdownFormatter:
+    def setup_method(self) -> None:
+        self.formatter = MarkdownFormatter()
+
+    def test_format_valid_result(self) -> None:
+        result = {
+            "files": [
+                {
+                    "file": "test.py",
+                    "language": "python",
+                    "lines": 50,
+                    "functions": [{"name": "test_func", "start_line": 1, "end_line": 10, "parameters": [], "return_type": "str"}],
+                    "classes": [],
+                    "complexity": {"score": 5, "rating": "low"}
+                }
+            ],
+            "dependency_graph": {
+                "total_dependencies": 0,
+                "orphaned_files": 0,
+                "cycles_detected": 0,
+                "cycle_details": [],
+                "orphaned_details": [],
+                "edges": [],
+                "statistics": {}
+            }
+        }
+        output = self.formatter.format(result)
+        assert "# CodeSnap Analysis Report" in output
+        assert "## Overview" in output
+        assert "## File Structure" in output
+        assert "## Key Functions" in output
+        assert "## Dependencies" in output
+        assert "## Complexity Metrics" in output
+
+    def test_format_empty_result(self) -> None:
+        result = {
+            "files": [],
+            "dependency_graph": {
+                "total_dependencies": 0,
+                "orphaned_files": 0,
+                "cycles_detected": 0,
+                "cycle_details": [],
+                "orphaned_details": [],
+                "edges": [],
+                "statistics": {}
+            }
+        }
+        output = self.formatter.format(result)
+        assert "Total Files" in output
+
+    def test_includes_language_breakdown(self) -> None:
+        result = {
+            "files": [
+                {"file": "a.py", "language": "python", "lines": 10, "functions": [], "classes": [], "complexity": {}},
+                {"file": "b.js", "language": "javascript", "lines": 20, "functions": [], "classes": [], "complexity": {}}
+            ],
+            "dependency_graph": {
+                "total_dependencies": 0,
+                "orphaned_files": 0,
+                "cycles_detected": 0,
+                "cycle_details": [],
+                "orphaned_details": [],
+                "edges": [],
+                "statistics": {}
+            }
+        }
+        output = self.formatter.format(result)
+        assert "python: 1" in output or "python: 2" in output
+        assert "javascript:" in output
+
+    def test_shows_circular_dependencies(self) -> None:
+        result = {
+            "files": [
+                {"file": "a.py", "language": "python", "lines": 10, "functions": [], "classes": [], "complexity": {}},
+                {"file": "b.py", "language": "python", "lines": 10, "functions": [], "classes": [], "complexity": {}}
+            ],
+            "dependency_graph": {
+                "total_dependencies": 2,
+                "orphaned_files": 0,
+                "cycles_detected": 1,
+                "cycle_details": [["a.py", "b.py", "a.py"]],
+                "orphaned_details": [],
+                "edges": [{"from": "a.py", "to": "b.py"}, {"from": "b.py", "to": "a.py"}],
+                "statistics": {}
+            }
+        }
+        output = self.formatter.format(result)
+        assert "Circular Dependencies Detected" in output
+
+    def test_shows_high_complexity_files(self) -> None:
+        result = {
+            "files": [
+                {
+                    "file": "complex.py",
+                    "language": "python",
+                    "lines": 100,
+                    "functions": [],
+                    "classes": [],
+                    "complexity": {"score": 55, "rating": "high"}
+                }
+            ],
+            "dependency_graph": {
+                "total_dependencies": 0,
+                "orphaned_files": 0,
+                "cycles_detected": 0,
+                "cycle_details": [],
+                "orphaned_details": [],
+                "edges": [],
+                "statistics": {}
+            }
+        }
+        output = self.formatter.format(result)
+        assert "High Complexity Files" in output
+        assert "complex.py" in output