diff --git a/tests/test_indexers.py b/tests/test_indexers.py
new file mode 100644
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--- /dev/null
+++ b/tests/test_indexers.py
@@ -0,0 +1,342 @@
+"""Tests for the indexers."""
+
+import tempfile
+from pathlib import Path
+
+import pytest
+
+from src.indexer.openapi import OpenAPIIndexer
+from src.indexer.readme import READMEIndexer
+from src.indexer.code import CodeIndexer
+from src.models.document import SourceType
+
+
+class TestOpenAPIIndexer:
+    """Tests for the OpenAPI indexer."""
+
+    @pytest.fixture
+    def sample_openapi_yaml(self):
+        """Create a sample OpenAPI spec for testing."""
+        content = """
+openapi: "3.0.0"
+info:
+  title: Test API
+  version: "1.0.0"
+  description: A test API for unit testing
+
+paths:
+  /users:
+    get:
+      summary: List users
+      description: Get a list of all users
+      operationId: listUsers
+      tags:
+        - users
+      parameters:
+        - name: limit
+          in: query
+          schema:
+            type: integer
+          description: Maximum number of users
+      responses:
+        '200':
+          description: Successful response
+          content:
+            application/json:
+              schema:
+                type: array
+                items:
+                  type: object
+    post:
+      summary: Create user
+      operationId: createUser
+      tags:
+        - users
+      requestBody:
+        required: true
+        content:
+          application/json:
+            schema:
+              type: object
+              properties:
+                name:
+                  type: string
+                email:
+                  type: string
+      responses:
+        '201':
+          description: User created
+
+  /users/{userId}:
+    get:
+      summary: Get user
+      operationId: getUser
+      parameters:
+        - name: userId
+          in: path
+          required: true
+          schema:
+            type: integer
+
+components:
+  schemas:
+    User:
+      type: object
+      properties:
+        id:
+          type: integer
+        name:
+          type: string
+      required:
+        - id
+        - name
+"""
+        return content
+
+    def test_index_openapi_yaml(self, tmp_path, sample_openapi_yaml):
+        """Test indexing a YAML OpenAPI spec."""
+        file_path = tmp_path / "openapi.yaml"
+        file_path.write_text(sample_openapi_yaml)
+
+        indexer = OpenAPIIndexer()
+        documents = indexer.index(tmp_path, recursive=False)
+
+        assert len(documents) > 0
+        assert all(doc.source_type == SourceType.OPENAPI for doc in documents)
+
+        titles = [doc.title for doc in documents]
+        assert any("Test API" in title for title in titles)
+        assert any("GET" in title or "/users" in title for title in titles)
+
+    def test_index_openapi_json(self, tmp_path):
+        """Test indexing a JSON OpenAPI spec."""
+        content = """{
+  "openapi": "3.0.0",
+  "info": {
+    "title": "JSON API",
+    "version": "1.0.0"
+  },
+  "paths": {}
+}"""
+        file_path = tmp_path / "openapi.json"
+        file_path.write_text(content)
+
+        indexer = OpenAPIIndexer()
+        documents = indexer.index(tmp_path, recursive=False)
+
+        assert len(documents) > 0
+
+    def test_unsupported_file(self, tmp_path):
+        """Test that unsupported files are ignored."""
+        file_path = tmp_path / "test.txt"
+        file_path.write_text("This is not an OpenAPI spec")
+
+        indexer = OpenAPIIndexer()
+        documents = indexer.index(tmp_path, recursive=False)
+
+        assert len(documents) == 0
+
+
+class TestREADMEIndexer:
+    """Tests for the README indexer."""
+
+    @pytest.fixture
+    def sample_readme(self):
+        """Create a sample README for testing."""
+        content = """# Project Documentation
+
+This is a sample project for testing the README indexer.
+
+## Installation
+
+To install the project, run:
+
+```bash
+pip install myproject
+```
+
+## Usage
+
+The main function can be called as follows:
+
+```python
+from myproject import main
+main()
+```
+
+## Configuration
+
+You can configure the project using environment variables:
+
+- `API_KEY`: Your API key
+- `DEBUG`: Enable debug mode
+
+## API Reference
+
+### Endpoints
+
+- `GET /users` - List all users
+- `POST /users` - Create a new user
+"""
+        return content
+
+    def test_index_readme(self, tmp_path, sample_readme):
+        """Test indexing a README file."""
+        file_path = tmp_path / "README.md"
+        file_path.write_text(sample_readme)
+
+        indexer = READMEIndexer()
+        documents = indexer.index(tmp_path, recursive=False)
+
+        assert len(documents) > 0
+        assert all(doc.source_type == SourceType.README for doc in documents)
+
+        titles = [doc.title for doc in documents]
+        assert any("Project Documentation" in title for title in titles)
+
+    def test_section_extraction(self, tmp_path, sample_readme):
+        """Test that sections are properly extracted."""
+        file_path = tmp_path / "README.md"
+        file_path.write_text(sample_readme)
+
+        indexer = READMEIndexer()
+        documents = indexer.index(tmp_path, recursive=False)
+
+        assert len(documents) >= 1
+        content = documents[0].content
+        assert "Installation" in content
+        assert "Usage" in content
+
+    def test_unsupported_extension(self, tmp_path):
+        """Test that unsupported extensions are ignored."""
+        file_path = tmp_path / "readme.xyz"
+        file_path.write_text("# Readme")
+
+        indexer = READMEIndexer()
+        documents = indexer.index(tmp_path, recursive=False)
+
+        assert len(documents) == 0
+
+
+class TestCodeIndexer:
+    """Tests for the code indexer."""
+
+    @pytest.fixture
+    def sample_python(self):
+        """Create a sample Python file for testing."""
+        content = '''"""Sample module for testing."""
+
+
+def add_numbers(a, b):
+    """Add two numbers together.
+
+    Args:
+        a: First number
+        b: Second number
+
+    Returns:
+        The sum of a and b
+    """
+    return a + b
+
+
+class Calculator:
+    """A simple calculator class.
+
+    This class provides basic arithmetic operations.
+    """
+
+    def __init__(self, initial_value=0):
+        """Initialize the calculator.
+
+        Args:
+            initial_value: Starting value
+        """
+        self.value = initial_value
+
+    def add(self, number):
+        """Add a number to the current value.
+
+        Args:
+            number: Number to add
+        """
+        self.value += number
+'''
+        return content
+
+    def test_index_python(self, tmp_path, sample_python):
+        """Test indexing a Python file."""
+        file_path = tmp_path / "sample.py"
+        file_path.write_text(sample_python)
+
+        indexer = CodeIndexer()
+        documents = indexer.index(tmp_path, recursive=False)
+
+        assert len(documents) > 0
+        assert all(doc.source_type == SourceType.CODE for doc in documents)
+
+        titles = [doc.title for doc in documents]
+        assert any("add_numbers" in title for title in titles)
+        assert any("Calculator" in title for title in titles)
+
+    def test_function_docstring(self, tmp_path, sample_python):
+        """Test that function docstrings are extracted."""
+        file_path = tmp_path / "sample.py"
+        file_path.write_text(sample_python)
+
+        indexer = CodeIndexer()
+        documents = indexer.index(tmp_path, recursive=False)
+
+        add_doc = [d for d in documents if "add_numbers" in d.title]
+        if add_doc:
+            assert "Add two numbers" in add_doc[0].content
+
+    def test_class_docstring(self, tmp_path, sample_python):
+        """Test that class docstrings are extracted."""
+        file_path = tmp_path / "sample.py"
+        file_path.write_text(sample_python)
+
+        indexer = CodeIndexer()
+        documents = indexer.index(tmp_path, recursive=False)
+
+        calc_doc = [d for d in documents if "Calculator" in d.title]
+        if calc_doc:
+            assert "simple calculator" in calc_doc[0].content.lower()
+
+    def test_jsdoc_extraction(self, tmp_path):
+        """Test JSDoc comment extraction."""
+        content = '''
+/**
+ * Multiplies two numbers.
+ * @param {number} a - First number
+ * @param {number} b - Second number
+ * @returns {number} The product of a and b
+ */
+function multiply(a, b) {
+  return a * b;
+}
+
+/**
+ * A Greeter class.
+ * @class
+ */
+class Greeter {
+  /**
+   * Create a greeter.
+   * @param {string} name - Name to greet
+   */
+  constructor(name) {
+    this.name = name;
+  }
+}
+'''
+        file_path = tmp_path / "sample.js"
+        file_path.write_text(content)
+
+        indexer = CodeIndexer()
+        documents = indexer.index(tmp_path, recursive=False)
+
+        func_doc = [d for d in documents if "multiply" in d.title]
+        if func_doc:
+            assert "Multiplies two numbers" in func_doc[0].content
+            assert "number" in func_doc[0].content