diff --git a/.gitignore b/.gitignore
index a0d6cccf6..1edf02c74 100644
--- a/.gitignore
+++ b/.gitignore
@@ -113,3 +113,8 @@ venv.bak/
 
 src/server.py
 
+# dia temporary files
+*.dia~
+
+# environment variable files
+setenvs*
diff --git a/tests/test_middlewares.py b/tests/test_middlewares.py
new file mode 100644
index 000000000..84bad576b
--- /dev/null
+++ b/tests/test_middlewares.py
@@ -0,0 +1,96 @@
+"""Module for testing ``swift_browser_ui.middlewares``."""
+
+
+from aiohttp.web import HTTPUnauthorized, HTTPForbidden, HTTPNotFound
+from aiohttp.web import Response, HTTPClientError, FileResponse
+import asynctest
+
+from swift_browser_ui.middlewares import error_middleware
+from swift_browser_ui.front import index
+
+
+async def return_401_handler(with_exception):
+    """Return an HTTP401 error."""
+    if with_exception:
+        raise HTTPUnauthorized()
+    return Response(
+        status=401
+    )
+
+
+async def return_403_handler(with_exception):
+    """Return an HTTP403 error."""
+    if with_exception:
+        raise HTTPForbidden()
+    return Response(
+        status=403
+    )
+
+
+async def return_404_handler(with_exception):
+    """Return or raise an HTTP404 error."""
+    if with_exception:
+        raise HTTPNotFound()
+    return Response(
+        status=404
+    )
+
+
+async def return_400_handler(with_exception):
+    """Return or raise an HTTP400 error."""
+    if with_exception:
+        raise HTTPClientError()
+    return Response(
+        status=400
+    )
+
+
+class MiddlewareTestClass(asynctest.TestCase):
+    """Testing the error middleware."""
+
+    async def test_401_return(self):
+        """Test 401 middleware when the 401 status is returned."""
+        resp = await error_middleware(None, return_401_handler)
+        self.assertEqual(resp.status, 401)
+        self.assertIsInstance(resp, FileResponse)
+
+    async def test_401_exception(self):
+        """Test 401 middleware when the 401 status is risen."""
+        resp = await error_middleware(True, return_401_handler)
+        self.assertEqual(resp.status, 401)
+        self.assertIsInstance(resp, FileResponse)
+
+    async def test_403_return(self):
+        """Test 403 middleware when the 403 status is returned."""
+        resp = await error_middleware(None, return_403_handler)
+        self.assertEqual(resp.status, 403)
+        self.assertIsInstance(resp, FileResponse)
+
+    async def test_403_exception(self):
+        """Test 403 middleware when the 403 status is risen."""
+        resp = await error_middleware(True, return_403_handler)
+        self.assertEqual(resp.status, 403)
+        self.assertIsInstance(resp, FileResponse)
+
+    async def test_404_return(self):
+        """Test 404 middleware when the 404 status is returned."""
+        resp = await error_middleware(None, return_404_handler)
+        self.assertEqual(resp.status, 404)
+        self.assertIsInstance(resp, FileResponse)
+
+    async def test_404_exception(self):
+        """Test 404 middlewrae when the 404 status is risen."""
+        resp = await error_middleware(True, return_404_handler)
+        self.assertEqual(resp.status, 404)
+        self.assertIsInstance(resp, FileResponse)
+
+    async def test_error_middleware_no_error(self):
+        """Test the general error middleware with correct status."""
+        resp = await error_middleware(None, index)
+        self.assertEqual(resp.status, 200)
+        self.assertIsInstance(resp, FileResponse)
+
+    async def test_error_middleware_non_handled_raise(self):
+        """Test the general error middleware with other status code."""
+        with self.assertRaises(HTTPClientError):
+            await error_middleware(True, return_400_handler)