diff --git a/Lib/test/test_subprocess.py b/Lib/test/test_subprocess.py
index 4f9cceb..854e43d 100644
--- a/Lib/test/test_subprocess.py
+++ b/Lib/test/test_subprocess.py
@@ -717,24 +717,20 @@
     def _kill_process(self, method, *args):
         # Do not inherit file handles from the parent.
         # It should fix failures on some platforms.
-        p = subprocess.Popen([sys.executable, "-c", "input()"], close_fds=True,
-                             stdin=subprocess.PIPE, stderr=subprocess.PIPE)
-
-        # Let the process initialize (Issue #3137)
-        time.sleep(0.1)
-        # The process should not terminate prematurely
-        self.assertIsNone(p.poll())
-        # Retry if the process do not receive the signal.
-        count, maxcount = 0, 3
-        while count < maxcount and p.poll() is None:
-            getattr(p, method)(*args)
-            time.sleep(0.1)
-            count += 1
-
-        self.assertIsNotNone(p.poll(), "the subprocess did not terminate")
-        if count > 1:
-            print >>sys.stderr, ("p.{}{} succeeded after "
-                                 "{} attempts".format(method, args, count))
+        p = subprocess.Popen([sys.executable, "-c", """if 1:
+                             import sys, time
+                             sys.stdout.write('x\\n')
+                             sys.stdout.flush()
+                             time.sleep(30)
+                             """],
+                             close_fds=True,
+                             stdin=subprocess.PIPE,
+                             stdout=subprocess.PIPE,
+                             stderr=subprocess.PIPE)
+        # Wait for the interpreter to be completely initialized before
+        # sending any signal.
+        p.stdout.read(1)
+        getattr(p, method)(*args)
         return p
 
     def test_send_signal(self):
diff --git a/Lib/test/test_threading.py b/Lib/test/test_threading.py
index 2e2558a..d97b062 100644
--- a/Lib/test/test_threading.py
+++ b/Lib/test/test_threading.py
@@ -307,7 +307,7 @@
         # Issue1733757
         # Avoid a deadlock when sys.settrace steps into threading._shutdown
         import subprocess
-        rc = subprocess.call([sys.executable, "-c", """if 1:
+        p = subprocess.Popen([sys.executable, "-c", """if 1:
             import sys, threading
 
             # A deadlock-killer, to prevent the
@@ -327,9 +327,14 @@
                 return func
 
             sys.settrace(func)
-            """])
+            """],
+            stdout=subprocess.PIPE,
+            stderr=subprocess.PIPE)
+        stdout, stderr = p.communicate()
+        rc = p.returncode
         self.assertFalse(rc == 2, "interpreted was blocked")
-        self.assertTrue(rc == 0, "Unexpected error")
+        self.assertTrue(rc == 0,
+                        "Unexpected error: " + repr(stderr))
 
     def test_join_nondaemon_on_shutdown(self):
         # Issue 1722344