Tests: default tmpfs in rootfs.

test/test_go_isolation.py

@@ -327,6 +327,26 @@ class TestGoIsolation(TestApplicationGo):
         obj = self.getjson(url='/?file=/bin/sh')['body']
         self.assertEqual(obj['FileExists'], False, 'file should not exists')
 
+    def test_go_isolation_rootfs_default_tmpfs(self):
+        if not self.isolation_key('unprivileged_userns_clone'):
+            print('unprivileged clone is not available')
+            raise unittest.SkipTest()
+
+        if not self.isolation_key('mnt'):
+            print('mnt namespace is not supported')
+            raise unittest.SkipTest()
+
+        isolation = {
+            'namespaces': {'mount': True, 'credential': True},
+            'rootfs': self.testdir,
+        }
+
+        self.load('ns_inspect', isolation=isolation)
+
+        obj = self.getjson(url='/?file=/tmp')['body']
+
+        self.assertEqual(obj['FileExists'], True, 'app has /tmp')
+
 
 if __name__ == '__main__':
     TestGoIsolation.main()