Fix the tests readme (#3786)
Fix the tests readme (#3786)

* Fix the tests readme

* Fix link to main README.md

* Create a user with an empty password, not database


Former-commit-id: 1d44500fb9b29e06997daea303b868536a0fa56c
Former-commit-id: 9ccb223f2ae27b0255a4f662b10a666ef6b60908
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