oeqa/runtime/systemd: wait for services to start/fail

When checking that no services have failed to start, actually wait for services
to finish starting by waiting for there not be no units in the "activating"
state.

(From OE-Core rev: 4d6422a84eba005a6fd788ce18c9dd42b079e2a8)

Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Saul Wold <sgw@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/lib/oeqa/runtime/systemd.py

@@ -32,8 +32,36 @@ class SystemdBasicTests(SystemdTest):
     def test_systemd_list(self):
         self.systemctl('list-unit-files')
 
+    def settle(self):
+        """
+        Block until systemd has finished activating any units being activated,
+        or until two minutes has elapsed.
+
+        Returns a tuple, either (True, None) if all units have finished
+        acitvating, or (False, message string) if there are still units
+        activating (generally, failing units that restart).
+        """
+        import time
+        settled = False
+        endtime = time.time() + (60 * 2)
+        while time.time() < endtime:
+            status = self.target.run('systemctl --state=activating | grep -q "0 loaded units listed"')
+            if status == 0:
+                settled = True
+                break
+            time.sleep(10)
+
+        if settled:
+            return (True, None)
+        else:
+            status, output = self.target.run('systemctl --state=activating')
+        return (settled, output)
+
     @skipUnlessPassed('test_systemd_basic')
     def test_systemd_failed(self):
+        settled, output = self.settle()
+        self.assertTrue(settled, msg="Timed out waiting for systemd to settle:\n" + output)
+
         output = self.systemctl('list-units', '--failed')
         match = re.search("0 loaded units listed", output)
         if not match: