parent_test: Refactor `wait_for_child`

Signed-off-by: Marc Hartmayer <mhartmay@linux.ibm.com>

tests/parent_test.py

@@ -2,7 +2,6 @@ import errno
 import fcntl
 import os
 import signal
-import sys
 import time
 import unittest
 
@@ -21,23 +20,6 @@ except NameError:
     from io import FileIO as file
 
 
-def wait_for_child(pid, timeout=1.0):
-    deadline = mitogen.core.now() + timeout
-    while timeout < mitogen.core.now():
-        try:
-            target_pid, status = os.waitpid(pid, os.WNOHANG)
-            if target_pid == pid:
-                return
-        except OSError:
-            e = sys.exc_info()[1]
-            if e.args[0] == errno.ECHILD:
-                return
-
-        time.sleep(0.05)
-
-    assert False, "wait_for_child() timed out"
-
-
 @mitogen.core.takes_econtext
 def call_func_in_sibling(ctx, econtext, sync_sender):
     recv = ctx.call_async(time.sleep, 99999)
@@ -106,7 +88,7 @@ class ReapChildTest(testlib.RouterMixin, testlib.TestCase):
         self.assertRaises(mitogen.core.TimeoutError,
             lambda: conn.connect(context=mitogen.core.Context(None, 1234))
         )
-        wait_for_child(conn.proc.pid)
+        testlib.wait_for_child(conn.proc.pid)
         e = self.assertRaises(OSError,
             lambda: os.kill(conn.proc.pid, 0)
         )
@@ -165,7 +147,7 @@ class ContextTest(testlib.RouterMixin, testlib.TestCase):
         local = self.router.local()
         pid = local.call(os.getpid)
         local.shutdown(wait=True)
-        wait_for_child(pid)
+        testlib.wait_for_child(pid)
         self.assertRaises(OSError, lambda: os.kill(pid, 0))
 
 

tests/testlib.py

@@ -86,6 +86,23 @@ if faulthandler is not None:
 mitogen.core.LOG.propagate = True
 
 
+def wait_for_child(pid, timeout=1.0):
+    deadline = mitogen.core.now() + timeout
+    while timeout < mitogen.core.now():
+        try:
+            target_pid, status = os.waitpid(pid, os.WNOHANG)
+            if target_pid == pid:
+                return
+        except OSError:
+            e = sys.exc_info()[1]
+            if e.args[0] == errno.ECHILD:
+                return
+
+        time.sleep(0.05)
+
+    assert False, "wait_for_child() timed out"
+
+
 def base_executable(executable=None):
     '''Return the path of the Python executable used to create the virtualenv.
     '''