I have been on several projects where a developer's version control branch needs to pass continious integration (CI in CI/CD) on a remote service before it is eligible to be merged. The implication here is that a successful remote test run is sufficient validation for acceptance. But given that the remote CI environment is also unlike the production environment I have been wondering why do we accept this validation over a local validation?
It seems to me that an organization should strive to enable local validation over remote validation if only for its cost benefits. Central CI environments are costly to operate. A common consequence of this is that these costs are reduced by having several test runs share an environment. Tests fail not due to a developer’s negligence but to the missing isolation. Validation now requires multiple runs in the hope that the next one will avoid all the conflicts and pass. It is CI wack-a-mole style, a style that costs too much and delays feature releases.
All developer machines are capable enough to run CI in the background while development happens in the foreground. The only thing that is missing is a signifier that authenticates the successful run. Eg, a value tied to the code commit, the successful test run log commit, and the environment commit.