diff --git a/tests/test_formatter.py b/tests/test_formatter.py
new file mode 100644
index 0000000..6d8bdab
--- /dev/null
+++ b/tests/test_formatter.py
@@ -0,0 +1,71 @@
+import pytest
+from pathlib import Path
+from codechunk.core.formatter import OutputFormatter
+from codechunk.core.chunking import ParsedChunk, ChunkMetadata
+
+
+class TestOutputFormatter:
+    """Tests for OutputFormatter."""
+
+    def test_format_markdown(self, sample_python_code, tmp_path):
+        """Test markdown output format."""
+        formatter = OutputFormatter(format_type="markdown")
+
+        from codechunk.core.parser import CodeParser
+        parser = CodeParser()
+        file_path = tmp_path / "test.py"
+        file_path.write_text(sample_python_code)
+
+        chunks = parser.parse_file(file_path)
+        output = formatter.format(chunks)
+
+        assert "# Code Context" in output
+        assert len(output) > 0
+
+    def test_format_ollama(self, sample_python_code, tmp_path):
+        """Test Ollama output format."""
+        formatter = OutputFormatter(format_type="ollama")
+
+        from codechunk.core.parser import CodeParser
+        parser = CodeParser()
+        file_path = tmp_path / "test.py"
+        file_path.write_text(sample_python_code)
+
+        chunks = parser.parse_file(file_path)
+        output = formatter.format(chunks)
+
+        assert "### System" in output
+        assert "### User" in output
+
+    def test_format_lmstudio(self, sample_python_code, tmp_path):
+        """Test LM Studio output format."""
+        formatter = OutputFormatter(format_type="lmstudio")
+
+        from codechunk.core.parser import CodeParser
+        parser = CodeParser()
+        file_path = tmp_path / "test.py"
+        file_path.write_text(sample_python_code)
+
+        chunks = parser.parse_file(file_path)
+        output = formatter.format(chunks)
+
+        assert output.strip().startswith("[")
+        assert output.strip().endswith("]")
+
+    def test_estimate_tokens(self):
+        """Test token estimation."""
+        formatter = OutputFormatter()
+
+        text = "This is a test string with about twenty words in it"
+        tokens = formatter.estimate_tokens(text)
+
+        assert tokens > 0
+        assert tokens < len(text)
+
+    def test_empty_chunks(self):
+        """Test formatting with no chunks."""
+        formatter = OutputFormatter(format_type="markdown")
+
+        output = formatter.format([])
+
+        assert len(output) > 0