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_file_utils.py

@@ -0,0 +1,98 @@
+from codesnap.utils.file_utils import FileUtils
+
+
+class TestFileUtils:
+    def test_should_ignore_patterns(self) -> None:
+        assert FileUtils.should_ignore("test.pyc", ["*.pyc"]) is True
+        assert FileUtils.should_ignore("test.pyc", ["*.pyc", "*.pyo"]) is True
+        assert FileUtils.should_ignore("test.py", ["*.pyc"]) is False
+
+    def test_should_ignore_directory(self) -> None:
+        assert FileUtils.should_ignore("src/__pycache__", ["__pycache__/*"]) is True
+        assert FileUtils.should_ignore(".git/config", [".git/*"]) is True
+
+    def test_is_text_file(self) -> None:
+        assert FileUtils.is_text_file("test.py") is True
+        assert FileUtils.is_text_file("test.js") is True
+        assert FileUtils.is_text_file("test.tsx") is True
+        assert FileUtils.is_text_file("Dockerfile") is True
+
+    def test_is_not_binary_file(self) -> None:
+        assert FileUtils.is_text_file("test.png") is False
+        assert FileUtils.is_text_file("test.jpg") is False
+        assert FileUtils.is_text_file("test.so") is False
+
+    def test_read_file_content(self) -> None:
+        import os
+        import tempfile
+        with tempfile.NamedTemporaryFile(mode='w', suffix='.py', delete=False) as f:
+            f.write("print('hello')")
+            temp_path = f.name
+        try:
+            content = FileUtils.read_file_content(temp_path)
+            assert content == "print('hello')"
+        finally:
+            os.unlink(temp_path)
+
+    def test_read_file_content_not_found(self) -> None:
+        content = FileUtils.read_file_content("/nonexistent/file.py")
+        assert content is None
+
+    def test_count_lines(self) -> None:
+        content = "line1\nline2\nline3"
+        assert FileUtils.count_lines(content) == 3
+        assert FileUtils.count_lines("") == 1
+        assert FileUtils.count_lines("single") == 1
+
+    def test_get_relative_path(self) -> None:
+        import os
+        import tempfile
+        with tempfile.TemporaryDirectory() as tmpdir:
+            subdir = os.path.join(tmpdir, "subdir")
+            os.makedirs(subdir)
+            filepath = os.path.join(subdir, "test.py")
+            rel = FileUtils.get_relative_path(filepath, tmpdir)
+            assert rel == os.path.join("subdir", "test.py")
+
+    def test_walk_directory(self) -> None:
+        import os
+        import tempfile
+        with tempfile.TemporaryDirectory() as tmpdir:
+            os.makedirs(os.path.join(tmpdir, "src"))
+            os.makedirs(os.path.join(tmpdir, "tests"))
+            with open(os.path.join(tmpdir, "main.py"), "w") as f:
+                f.write("print('hello')")
+            with open(os.path.join(tmpdir, "src", "module.py"), "w") as f:
+                f.write("def test(): pass")
+
+            files = FileUtils.walk_directory(tmpdir, ["*.pyc", "__pycache__/*"], 100)
+            assert len(files) == 2
+
+    def test_walk_directory_with_ignore(self) -> None:
+        import os
+        import tempfile
+        with tempfile.TemporaryDirectory() as tmpdir:
+            os.makedirs(os.path.join(tmpdir, "__pycache__"))
+            with open(os.path.join(tmpdir, "main.py"), "w") as f:
+                f.write("print('hello')")
+            with open(os.path.join(tmpdir, "__pycache__", "cache.pyc"), "w") as f:
+                f.write("cached")
+
+            files = FileUtils.walk_directory(tmpdir, ["*.pyc", "__pycache__/*"], 100)
+            assert len(files) == 1
+            assert "__pycache__" not in files[0]
+
+    def test_get_directory_tree(self) -> None:
+        import os
+        import tempfile
+        with tempfile.TemporaryDirectory() as tmpdir:
+            os.makedirs(os.path.join(tmpdir, "src"))
+            os.makedirs(os.path.join(tmpdir, "tests"))
+            with open(os.path.join(tmpdir, "main.py"), "w") as f:
+                f.write("")
+            with open(os.path.join(tmpdir, "src", "module.py"), "w") as f:
+                f.write("")
+
+            tree = FileUtils.get_directory_tree(tmpdir, ["*.pyc"], 3)
+            assert len(tree) > 0
+            assert any("main.py" in line for line in tree)