Uncle Bob's rules for TDD are specified here.You are not allowed to write any production code unless it is tomake a failing unit test pass. You are not allowed to write any moreof a unit test than is sufficient to fail; and compilation failuresare failures. You are not allowed to write any more production codethan is sufficient to pass the one failing unit test.But, is it ok to write a bunch of tests that pass as soon as the test compiles?  For example, a test that asserts null and the default impl of a method I'm testing returns null.  Am I doing something wrong by doing this?  Should I skip to the first test that will fail or is it ok to write tests that automatically pass first?
Can I start with a passing unit test?
testing;tdd
No, because it is possible to write a test that inadvertently passes when it should actually fail.  That's why you make it fail first, so that you can demonstrate transitioning from a failed state to a passed state where you're testing the actual functionality that you want, rather than having a bogus test that passes and makes you think that your code actually works, when in fact it doesn't.