Integration tests are slow and difficult to maintain because they have substantially more system touch points than unit tests and hence change more often. These elaborate or sophisticated tests provide a role that unit tests cannot replace, thus there is no way to avoid creating them while focusing solely on unit tests.

Successful software teams are continuously searching for methods to improve the efficiency of its members. They recognize that enhancing the development process is a solid method to increase quality while decreasing time to market. This may necessitate the addition of new tools, but it may also necessitate a step back from day-to-day work to take a fresh look at what we're doing. Think about testing.

Needless to say that flaky builds reduce productivity and reduce the value of your tests and those unreliable builds are dangerous to all developers.