diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 433c1b9..f85a3a1 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -1,3 +1,5 @@
+name: Test
+
 on: pull_request
 
 jobs:
diff --git a/pyproject.toml b/pyproject.toml
index a4c028d..d6e4998 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -51,6 +51,7 @@ dev = [
     "pydantic-settings>=2.6.1",
     "pytest-asyncio>=0.24.0",
     "pytest-cov>=6.0.0",
+    "pytest-dotenv>=0.5.2",
     "pytest-mock>=3.14.0",
     "pytest>=8.3.4",
     "respx>=0.21.1",
@@ -63,3 +64,4 @@ dev = [
 addopts = "-v -x --cov=src --cov-report=term-missing:skip-covered"
 asyncio_mode = "auto"
 asyncio_default_fixture_loop_scope = "function"
+env_files = ["tests/.env.test"]
diff --git a/src/fastapi_zitadel_auth/models.py b/src/fastapi_zitadel_auth/models.py
index 011df5e..057f44a 100644
--- a/src/fastapi_zitadel_auth/models.py
+++ b/src/fastapi_zitadel_auth/models.py
@@ -1,4 +1,4 @@
-from typing import Any, List, Optional
+from typing import Any, List
 from pydantic import BaseModel, Field
 
 
diff --git a/tests/.env.test b/tests/.env.test
new file mode 100644
index 0000000..e2d81c1
--- /dev/null
+++ b/tests/.env.test
@@ -0,0 +1,3 @@
+ZITADEL_HOST=https://test-zitadel-xs2hs.zitadel.cloud
+ZITADEL_PROJECT_ID=123456789
+OAUTH_CLIENT_ID=7777777777
diff --git a/tests/test_config.py b/tests/test_config.py
new file mode 100644
index 0000000..837b06b
--- /dev/null
+++ b/tests/test_config.py
@@ -0,0 +1,92 @@
+"""
+Test the auth config module
+"""
+
+import pytest
+from pydantic import ValidationError
+
+from fastapi_zitadel_auth.config import AuthConfig
+
+
+@pytest.fixture
+def valid_config_data() -> dict:
+    """
+    Valid configuration data for testing
+    """
+    return {
+        "client_id": "test-client-123",
+        "project_id": "proj-123",
+        "base_url": "https://auth.example.com/",
+    }
+
+
+class TestAuthConfig:
+    """Test suite for AuthConfig class"""
+
+    def test_valid_config(self, valid_config_data):
+        """Test creating config with valid data"""
+        config = AuthConfig(**valid_config_data)
+        assert config.client_id == "test-client-123"
+        assert config.project_id == "proj-123"
+        assert str(config.base_url) == "https://auth.example.com/"
+        assert config.algorithm == "RS256"  # default value
+        assert config.scopes is None  # default value
+
+    def test_computed_issuer(self, valid_config_data):
+        """Test issuer computed field removes trailing slash"""
+        config = AuthConfig(**valid_config_data)
+        assert config.issuer == "https://auth.example.com"
+
+        # Test without trailing slash
+        valid_config_data["base_url"] = "https://auth.example.com"
+        config = AuthConfig(**valid_config_data)
+        assert config.issuer == "https://auth.example.com"
+
+    def test_computed_urls(self, valid_config_data):
+        """Test computed URL fields"""
+        config = AuthConfig(**valid_config_data)
+
+        assert config.jwks_url == "https://auth.example.com/oauth/v2/keys"
+        assert config.authorization_url == "https://auth.example.com/oauth/v2/authorize"
+        assert config.token_url == "https://auth.example.com/oauth/v2/token"
+
+    def test_custom_scopes(self, valid_config_data):
+        """Test configuration with custom scopes"""
+        valid_config_data["scopes"] = {
+            "openid": "OpenID scope",
+            "profile": "Profile information",
+        }
+        config = AuthConfig(**valid_config_data)
+        assert config.scopes == {
+            "openid": "OpenID scope",
+            "profile": "Profile information",
+        }
+
+    def test_custom_algorithm(self, valid_config_data):
+        """Test configuration with custom algorithm"""
+        valid_config_data["algorithm"] = "ES256"
+        config = AuthConfig(**valid_config_data)
+        assert config.algorithm == "ES256"
+
+    def test_invalid_url(self, valid_config_data):
+        """Test validation error for invalid URL"""
+        valid_config_data["base_url"] = "not-a-url"
+        with pytest.raises(ValidationError) as exc_info:
+            AuthConfig(**valid_config_data)
+        errors = exc_info.value.errors()
+        assert any(error["type"] == "url_parsing" for error in errors)
+
+    def test_missing_required_fields(self):
+        """Test validation error for missing required fields"""
+        with pytest.raises(ValidationError) as exc_info:
+            AuthConfig()
+        errors = exc_info.value.errors()
+        required_fields = {"client_id", "project_id", "base_url"}
+        error_fields = {error["loc"][0] for error in errors}
+        assert required_fields.issubset(error_fields)
+
+    def test_config_immutability(self, valid_config_data):
+        """Test that config is immutable after creation"""
+        config = AuthConfig(**valid_config_data)
+        with pytest.raises(Exception):
+            config.client_id = "new-client"  # type: ignore
diff --git a/uv.lock b/uv.lock
index 34d8ff0..320143b 100644
--- a/uv.lock
+++ b/uv.lock
@@ -283,6 +283,7 @@ dev = [
     { name = "pytest" },
     { name = "pytest-asyncio" },
     { name = "pytest-cov" },
+    { name = "pytest-dotenv" },
     { name = "pytest-mock" },
     { name = "respx" },
     { name = "ruff" },
@@ -307,6 +308,7 @@ dev = [
     { name = "pytest", specifier = ">=8.3.4" },
     { name = "pytest-asyncio", specifier = ">=0.24.0" },
     { name = "pytest-cov", specifier = ">=6.0.0" },
+    { name = "pytest-dotenv", specifier = ">=0.5.2" },
     { name = "pytest-mock", specifier = ">=3.14.0" },
     { name = "respx", specifier = ">=0.21.1" },
     { name = "ruff", specifier = ">=0.8.1" },
@@ -637,6 +639,19 @@ wheels = [
     { url = "https://files.pythonhosted.org/packages/36/3b/48e79f2cd6a61dbbd4807b4ed46cb564b4fd50a76166b1c4ea5c1d9e2371/pytest_cov-6.0.0-py3-none-any.whl", hash = "sha256:eee6f1b9e61008bd34975a4d5bab25801eb31898b032dd55addc93e96fcaaa35", size = 22949 },
 ]
 
+[[package]]
+name = "pytest-dotenv"
+version = "0.5.2"
+source = { registry = "https://pypi.org/simple" }
+dependencies = [
+    { name = "pytest" },
+    { name = "python-dotenv" },
+]
+sdist = { url = "https://files.pythonhosted.org/packages/cd/b0/cafee9c627c1bae228eb07c9977f679b3a7cb111b488307ab9594ba9e4da/pytest-dotenv-0.5.2.tar.gz", hash = "sha256:2dc6c3ac6d8764c71c6d2804e902d0ff810fa19692e95fe138aefc9b1aa73732", size = 3782 }
+wheels = [
+    { url = "https://files.pythonhosted.org/packages/d0/da/9da67c67b3d0963160e3d2cbc7c38b6fae342670cc8e6d5936644b2cf944/pytest_dotenv-0.5.2-py3-none-any.whl", hash = "sha256:40a2cece120a213898afaa5407673f6bd924b1fa7eafce6bda0e8abffe2f710f", size = 3993 },
+]
+
 [[package]]
 name = "pytest-mock"
 version = "3.14.0"