diff --git a/python/samba/tests/__init__.py b/python/samba/tests/__init__.py
index 2c8fa192137..0f3f09e6db1 100644
--- a/python/samba/tests/__init__.py
+++ b/python/samba/tests/__init__.py
@@ -1119,20 +1119,22 @@ class BlackboxTestCase(TestCaseInTempDir):
                              stdout=subprocess.PIPE,
                              stderr=subprocess.PIPE,
                              shell=True)
-        retcode = p.wait()
+        stdoutdata, stderrdata = p.communicate()
+        retcode = p.returncode
         if retcode != expected:
             raise BlackboxProcessError(retcode,
                                        line,
-                                       p.stdout.read(),
-                                       p.stderr.read())
+                                       stdoutdata,
+                                       stderrdata)
 
     def check_output(self, line):
         line = self._make_cmdline(line)
         p = subprocess.Popen(line, stdout=subprocess.PIPE, stderr=subprocess.PIPE, shell=True, close_fds=True)
-        retcode = p.wait()
+        stdoutdata, stderrdata = p.communicate()
+        retcode = p.returncode
         if retcode:
-            raise BlackboxProcessError(retcode, line, p.stdout.read(), p.stderr.read())
-        return p.stdout.read()
+            raise BlackboxProcessError(retcode, line, stdoutdata, stderrdata)
+        return stdoutdata
 
 
 def connect_samdb(samdb_url, lp=None, session_info=None, credentials=None,