3 files changed, 39 insertions, 1 deletions
diff --git a/python/tests/Makefile.am b/python/tests/Makefile.am
index 490b272..219812c 100644
--- a/python/tests/Makefile.am
+++ b/python/tests/Makefile.am
@@ -9,4 +9,5 @@
 
 MAINTAINERCLEANFILES    = Makefile.in
 
-EXTRA_DIST = $(wildcard test_*)
+EXTRA_DIST = $(wildcard test_*) \
+	     __init__.py
diff --git a/python/tests/__init__.py b/python/tests/__init__.py
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/python/tests/__init__.py
diff --git a/python/tests/test_cts_network.py b/python/tests/test_cts_network.py
new file mode 100644
index 0000000..4aea8b9
--- /dev/null
+++ b/python/tests/test_cts_network.py
@@ -0,0 +1,37 @@
+# These warnings are not useful in unit tests.
+# pylint: disable=missing-class-docstring,missing-function-docstring,missing-module-docstring
+
+__copyright__ = "Copyright 2023 the Pacemaker project contributors"
+__license__ = "GPLv2+"
+
+import unittest
+
+from pacemaker._cts.network import next_ip
+
+# next_ip makes a bunch of assumptions that we are not going to test here:
+#
+# * The env argument actually contains an "IPBase" key with a string in it
+# * The string is a properly formatted IPv4 or IPv6 address, with no extra
+#   leading or trailing whitespace
+
+class NextIPTestCase(unittest.TestCase):
+    def test_ipv4(self):
+        # The first time next_ip is called, it will read the IPBase out of
+        # the environment.  After that, it just goes off whatever it
+        # previously returned, so the environment value doesn't matter.
+        self.assertEqual(next_ip("1.1.1.1"), "1.1.1.2")
+        self.assertEqual(next_ip(), "1.1.1.3")
+
+        # Passing reset=True will force it to re-read the environment.  Here,
+        # we use that to ask it for a value outside of the available range.
+        self.assertRaises(ValueError, next_ip, "1.1.1.255", reset=True)
+
+    def test_ipv6(self):
+        # Same comments as for the test_ipv4 function, plus we need to reset
+        # here because otherwise it will remember what happened in that function.
+        self.assertEqual(next_ip("fe80::fc54:ff:fe09:101", reset=True),
+                         "fe80::fc54:ff:fe09:102")
+        self.assertEqual(next_ip(),
+                         "fe80::fc54:ff:fe09:103")
+
+        self.assertRaises(ValueError, next_ip, "fe80::fc54:ff:fe09:ffff", reset=True)