Certified Development Lifecycle and Deployment Architect

A developer on the Universal Containers team has created a test class for a method that involves a web-service callout. In the test class, the developer should load test data, create an instance of the Mock object, set Test.setMock() to that Mock object, call startTest(), execute the code that performs the callout, call stopTest(), and compare the result against expectations. Unfortunately, the developer omitted the Test.setMock() step.

What happens when the developer runs this test class?