Add a server console-log test with unlimited length

Now server console-log API is important for debugging gate problems
and the API is called with unlimited length for debugging. However,
there is not the API test with unlimited length.
This patch adds the test.

Change-Id: I5a35f086deddfcd54e995cb1156699592d1daea6
diff --git a/tempest/api/compute/servers/test_server_actions.py b/tempest/api/compute/servers/test_server_actions.py
index 071bbfb..256ce0c 100644
--- a/tempest/api/compute/servers/test_server_actions.py
+++ b/tempest/api/compute/servers/test_server_actions.py
@@ -372,6 +372,25 @@
     @testtools.skipUnless(CONF.compute_feature_enabled.console_output,
                           'Console output not supported.')
     @test.attr(type='gate')
+    def test_get_console_output_with_unlimited_size(self):
+        _, server = self.create_test_server(wait_until='ACTIVE')
+
+        def _check_full_length_console_log():
+            _, output = self.servers_client.get_console_output(server['id'],
+                                                               None)
+            self.assertTrue(output, "Console output was empty.")
+            lines = len(output.split('\n'))
+
+            # NOTE: This test tries to get full length console log, and the
+            # length should be bigger than the one of test_get_console_output.
+            self.assertTrue(lines > 10, "Cannot get enough console log length."
+                                        " (lines: %s)" % lines)
+
+        self.wait_for(_check_full_length_console_log)
+
+    @testtools.skipUnless(CONF.compute_feature_enabled.console_output,
+                          'Console output not supported.')
+    @test.attr(type='gate')
     def test_get_console_output_server_id_in_shutoff_status(self):
         # Positive test:Should be able to GET the console output
         # for a given server_id in SHUTOFF status