The pernicious effect of having a separate testing team:

How Big Tech does Quality Assurance (QA) - by Gergely Orosz

The change in the number and type of tests the Visual Studio Team Services experienced after merging the dev and the test teams. Before the merge: end-to-end tests dominated, but unit and integration tests were rare. This flipped after the mergeBlogs

The change in the number and type of tests the Visual Studio Team Services experienced after merging the dev and the test teams. Before the merge: end-to-end tests dominated, but unit and integration tests were rare. This flipped after the merge. (Microsoft Dev Blogs)

In 2 years, almost all “old” tests from when test was separate from dev, were gone. The new tests became more granular as well

In 2 years, almost all “old” tests from when test was separate from dev, were gone. The new tests became more granular as well. (Microsoft Dev Blogs)