A team has started employing Test Driven Development in their project. They have started writing unit tests before the code, their code coverage percentage is also good based on the number of unit tests they are writing, and the tests are passing too. Still, there are some concerns shared by the code reviewers on the quality of production code. They have observed duplicate code, workarounds to bug fixes and instances of hardcoding in the code.

What could the team have possibly missed in implementing TDD$?$

Not written enough test cases

Not employed any unit test framework

Not reviewed code of test cases

Not paid adequate attention to refactoring