diff --git a/tests/Dockerfile b/tests/Dockerfile
index bf95cd6a..4705acca 100644
--- a/tests/Dockerfile
+++ b/tests/Dockerfile
@@ -5,8 +5,8 @@ ARG PYTHON_VERSION=3.10
 FROM python:${PYTHON_VERSION}
 
 ARG APT_MIRROR
-RUN sed -ri "s/(httpredir|deb).debian.org/${APT_MIRROR:-deb.debian.org}/g" /etc/apt/sources.list \
-    && sed -ri "s/(security).debian.org/${APT_MIRROR:-security.debian.org}/g" /etc/apt/sources.list
+RUN sed -ri "s/(httpredir|deb).debian.org/${APT_MIRROR:-deb.debian.org}/g" /etc/apt/sources.list.d/debian.sources \
+ && sed -ri "s/(security).debian.org/${APT_MIRROR:-security.debian.org}/g" /etc/apt/sources.list.d/debian.sources
 
 RUN apt-get update && apt-get -y install --no-install-recommends \
     gnupg2 \
diff --git a/tests/integration/api_container_test.py b/tests/integration/api_container_test.py
index 0cb8fec6..0782b12c 100644
--- a/tests/integration/api_container_test.py
+++ b/tests/integration/api_container_test.py
@@ -1392,7 +1392,7 @@ class GetContainerStatsTest(BaseAPIIntegrationTest):
         response = self.client.stats(container, stream=0)
         self.client.kill(container)
 
-        assert type(response) == dict
+        assert isinstance(response, dict)
         for key in ['read', 'networks', 'precpu_stats', 'cpu_stats',
                     'memory_stats', 'blkio_stats']:
             assert key in response
@@ -1405,7 +1405,7 @@ class GetContainerStatsTest(BaseAPIIntegrationTest):
             self.client.start(container)
             stream = self.client.stats(container)
             for chunk in stream:
-                assert type(chunk) == dict
+                assert isinstance(chunk, dict)
                 for key in ['read', 'network', 'precpu_stats', 'cpu_stats',
                             'memory_stats', 'blkio_stats']:
                     assert key in chunk
diff --git a/tests/integration/api_image_test.py b/tests/integration/api_image_test.py
index 6a6686e3..cb3d6671 100644
--- a/tests/integration/api_image_test.py
+++ b/tests/integration/api_image_test.py
@@ -32,7 +32,7 @@ class ListImagesTest(BaseAPIIntegrationTest):
 
     def test_images_quiet(self):
         res1 = self.client.images(quiet=True)
-        assert type(res1[0]) == str
+        assert isinstance(res1[0], str)
 
 
 class PullImageTest(BaseAPIIntegrationTest):
@@ -43,7 +43,7 @@ class PullImageTest(BaseAPIIntegrationTest):
             pass
         res = self.client.pull('hello-world')
         self.tmp_imgs.append('hello-world')
-        assert type(res) == str
+        assert isinstance(res, str)
         assert len(self.client.images('hello-world')) >= 1
         img_info = self.client.inspect_image('hello-world')
         assert 'Id' in img_info