We're just starting out with TFS, so just want to clarify the steps to get a piece of work through dev and testing (using the Agile template in 2012).
User Story - gather requirements, features, wishlists, etc
User Story then contains Tasks - small bits of work for the developer
After this does each task or user story (or both) need a test case, OR when a task state is "Closed" does it appear in the testers queue (using Microsoft Test Manager)?
How do we ensure that every task/bug is tested? What state does a developer set it to so it can be tested?
Test cases are attached to User Stories. You test the complete user story as soon as it's finished. The tester can use Microsoft Test Manager to start creating test cases at the start of the iteration. Since the user story is not implemented yet, those test cases will be in a Blocked state. Once the User Story is done, the tester starts testing it.
If the tester files a bug, this bug will then be triaged and a task will be created to fix it. This task will be picked up by a developer. When the developer finishes fixing the bug, the tester can use MTM to verify any open bugs. As soon as a bug fix is verified, the bug is closed.