Shift left testing with test automation

If you practice agile development and try to ship frequently, then manual testing isn't a scalable option. Even if you don't practice CI/CD and only ship on a sprint cadence, running all the necessary regression tests would take enormous manpower and a lot of time and money. But getting test automation right is not an easy task. Automated tests that have been created and maintained by a QA department or outsourced entity, for example, are not correlated with higher engineering velocity (Forsgren N., Humble, J., & Kim, G., 2018, Page 95). To notice an impact on your velocity, you need reliable tests that have been created and maintained by the team. The theory behind this is that if developers maintain tests, they produce more testable code.

Everybody knows what a good test portfolio should look like: you have a big base of automated unit tests (Level 0), fewer integration tests (Level 1), some integration tests that need test...