Step 7: write the third failing test
Step 7: write the third failing test

Note that in addition to verifying ensure throws (it will
actually use td's `log.fail` function), that it also asserts
this occurs prior to the other side-effect-having dependencies
so those are not called in this case.
testdouble/testdouble.js,testdouble/testdouble.js,testdouble/testdouble.js