Redirect stderr to stdout for tests.

tester.py

@@ -324,16 +324,13 @@ class Tester:
             log("Test start: %s UTC." % start_date.strftime("%Y-%m-%d %H:%M:%S"))
             # Run test
             p = subprocess.Popen(
-                command, stdin=sys.stdin, stdout=subprocess.PIPE, stderr=subprocess.PIPE
+                command, stdin=sys.stdin, stdout=subprocess.PIPE, stderr=subprocess.STDOUT
             )
             out, err = p.communicate()
             if out:
                 out = out.decode("utf-8").strip()
                 out_of_support = out_of_support or "out of support" in out
                 log(out)
-            if err:
-                err = err.decode("utf-8").strip()
-                log(err)
             if p.returncode == 0:
                 status = "\033[92msuccess\033[0m"
                 successes += 1