diff --git a/osbuild/testutil/net.py b/osbuild/testutil/net.py
index d2abb565..6dc8acca 100644
--- a/osbuild/testutil/net.py
+++ b/osbuild/testutil/net.py
@@ -7,6 +7,20 @@ import http.server
 import socket
 import threading
 
+try:
+    from http.server import ThreadingHTTPServer
+except ImportError:
+    # This fallback is only needed on py3.6. Py3.7+ has ThreadingHTTPServer.
+    # We just import ThreadingHTTPServer here so that the import of "net.py"
+    # on py36 works, the helpers are not usable because the "directory" arg
+    # for SimpleHTTPRequestHandler is also not supported.
+    class ThreadingHTTPServer:  # type: ignore
+        def __init__(self, *args, **kwargs):  # pylint: disable=unused-argument
+            # pylint: disable=import-outside-toplevel
+            import pytest  # type: ignore
+            pytest.skip("python too old to suport ThreadingHTTPServer")
+
+
 from .atomic import AtomicCounter
 
 
@@ -21,7 +35,7 @@ class SilentHTTPRequestHandler(http.server.SimpleHTTPRequestHandler):
         pass
 
 
-class DirHTTPServer(http.server.ThreadingHTTPServer):
+class DirHTTPServer(ThreadingHTTPServer):
     def __init__(self, *args, directory=None, simulate_failures=0, **kwargs):
         super().__init__(*args, **kwargs)
         self.directory = directory
diff --git a/sources/test/test_curl_source.py b/sources/test/test_curl_source.py
index 31308b9b..49813ad0 100644
--- a/sources/test/test_curl_source.py
+++ b/sources/test/test_curl_source.py
@@ -9,7 +9,7 @@ from unittest.mock import patch
 
 import pytest
 
-import osbuild.testutil.net
+from osbuild.testutil.net import http_serve_directory
 
 SOURCES_NAME = "org.osbuild.curl"
 
@@ -118,7 +118,7 @@ def test_curl_download_many_with_retry(tmp_path, sources_service):
     fake_httpd_root = tmp_path / "fake-httpd-root"
 
     simulate_failures = 2
-    with osbuild.testutil.net.http_serve_directory(fake_httpd_root, simulate_failures=simulate_failures) as httpd:
+    with http_serve_directory(fake_httpd_root, simulate_failures=simulate_failures) as httpd:
         test_sources = make_test_sources(fake_httpd_root, httpd.server_port, 5)
 
         sources_service.cache = tmp_path / "curl-download-dir"
@@ -134,7 +134,7 @@ def test_curl_download_many_with_retry(tmp_path, sources_service):
 def test_curl_download_many_chksum_validate(tmp_path, sources_service):
     fake_httpd_root = tmp_path / "fake-httpd-root"
 
-    with osbuild.testutil.net.http_serve_directory(fake_httpd_root) as httpd:
+    with http_serve_directory(fake_httpd_root) as httpd:
         test_sources = make_test_sources(fake_httpd_root, httpd.server_port, 5)
         # "break" the hash of file "1" by replacing the content to no longer
         # match the checksum
@@ -150,7 +150,7 @@ def test_curl_download_many_chksum_validate(tmp_path, sources_service):
 def test_curl_download_many_retries(tmp_path, sources_service):
     fake_httpd_root = tmp_path / "fake-httpd-root"
 
-    with osbuild.testutil.net.http_serve_directory(fake_httpd_root) as httpd:
+    with http_serve_directory(fake_httpd_root) as httpd:
         test_sources = make_test_sources(fake_httpd_root, httpd.server_port, 5)
         # remove all the sources
         shutil.rmtree(fake_httpd_root)