After the tests have been written, you should write enough code to implement the feature for the tests you wrote earlier. Bear in mind that the goal here is to try to employ good practices and standards in writing the code to make the test pass. All the approaches that lead to writing bad or stinking code should be avoided.
Try to avoid test overfitting, a situation where you write code just to make the tests pass. Instead you should write the code to implement the feature or user requirements fully, so as to ensure that every possible use case of the feature is covered to avoid situations where the code has different behaviors when executed by the test cases and when in production.
