TST: add test showing the missing key problem

unittests/test_apiutils.py

@@ -296,6 +296,19 @@ def test_merge_entities():
     assert r2.get_property("F").value == "text"
 
 
+def test_merge_bug_conflict():
+    r = db.Record()
+    r.add_property(name="C", value=4)
+    r2 = db.Record()
+    r2.add_property(name="C", value=4, datatype="TEXT")
+    merge_entities(r, r2)
+
+    r3 = db.Record()
+    r3.add_property(name="C", value=4, datatype="INTEGER")
+    with pytest.raises(RuntimeError) as excinfo:
+        merge_entities(r3, r2)
+
+
 def test_merge_bug_109():
     rt = db.RecordType(name="TestBug")
     p = db.Property(name="test_bug_property", datatype=db.LIST(db.INTEGER))