1 files changed, 22 insertions, 0 deletions
diff --git a/cloudinit/config/tests/test_mounts.py b/cloudinit/config/tests/test_mounts.py
new file mode 100644
index 00000000..c7dad61a
--- /dev/null
+++ b/cloudinit/config/tests/test_mounts.py
@@ -0,0 +1,22 @@
+# This file is part of cloud-init. See LICENSE file for license information.
+from unittest import mock
+
+from cloudinit.config.cc_mounts import create_swapfile
+
+
+M_PATH = 'cloudinit.config.cc_mounts.'
+
+
+class TestCreateSwapfile:
+
+    @mock.patch(M_PATH + 'util.subp')
+    def test_happy_path(self, m_subp, tmpdir):
+        swap_file = tmpdir.join("swap-file")
+        fname = str(swap_file)
+
+        # Some of the calls to util.subp should create the swap file; this
+        # roughly approximates that
+        m_subp.side_effect = lambda *args, **kwargs: swap_file.write('')
+
+        create_swapfile(fname, '')
+        assert mock.call(['mkswap', fname]) in m_subp.call_args_list