Add node, chai, jest diff comparison

README.md

@@ -65,3 +65,8 @@ See also:
 
 - Custom formatters: https://github.com/cucumber/cucumber-js/blob/master/docs/custom_formatters.md
 - Built-in formatters: https://github.com/cucumber/cucumber-js/tree/master/src/formatter.
+
+### assertion
+
+This package contains some failing tests demonstrating object diffs provided by
+node's native asserts, chai and jest.