1 files changed, 62 insertions, 0 deletions
diff --git a/tests/unittests/test_merging.py b/tests/unittests/test_merging.py
new file mode 100644
index 00000000..0037b966
--- /dev/null
+++ b/tests/unittests/test_merging.py
@@ -0,0 +1,62 @@
+from mocker import MockerTestCase
+
+from cloudinit import util
+
+
+class TestMergeDict(MockerTestCase):
+    def test_simple_merge(self):
+        """Test simple non-conflict merge."""
+        source = {"key1": "value1"}
+        candidate = {"key2": "value2"}
+        result = util.mergedict(source, candidate)
+        self.assertEqual({"key1": "value1", "key2": "value2"}, result)
+
+    def test_nested_merge(self):
+        """Test nested merge."""
+        source = {"key1": {"key1.1": "value1.1"}}
+        candidate = {"key1": {"key1.2": "value1.2"}}
+        result = util.mergedict(source, candidate)
+        self.assertEqual(
+            {"key1": {"key1.1": "value1.1", "key1.2": "value1.2"}}, result)
+
+    def test_merge_does_not_override(self):
+        """Test that candidate doesn't override source."""
+        source = {"key1": "value1", "key2": "value2"}
+        candidate = {"key1": "value2", "key2": "NEW VALUE"}
+        result = util.mergedict(source, candidate)
+        self.assertEqual(source, result)
+
+    def test_empty_candidate(self):
+        """Test empty candidate doesn't change source."""
+        source = {"key": "value"}
+        candidate = {}
+        result = util.mergedict(source, candidate)
+        self.assertEqual(source, result)
+
+    def test_empty_source(self):
+        """Test empty source is replaced by candidate."""
+        source = {}
+        candidate = {"key": "value"}
+        result = util.mergedict(source, candidate)
+        self.assertEqual(candidate, result)
+
+    def test_non_dict_candidate(self):
+        """Test non-dict candidate is discarded."""
+        source = {"key": "value"}
+        candidate = "not a dict"
+        result = util.mergedict(source, candidate)
+        self.assertEqual(source, result)
+
+    def test_non_dict_source(self):
+        """Test non-dict source is not modified with a dict candidate."""
+        source = "not a dict"
+        candidate = {"key": "value"}
+        result = util.mergedict(source, candidate)
+        self.assertEqual(source, result)
+
+    def test_neither_dict(self):
+        """Test if neither candidate or source is dict source wins."""
+        source = "source"
+        candidate = "candidate"
+        result = util.mergedict(source, candidate)
+        self.assertEqual(source, result)