The WCT testing framework supports “historical tests” and “historical files”. A “historical file” is simply one produced by a test and saved to the “history” category of the test data repository (see the data repository topic). A “historical test” is then a test that consumes these files.
A “historical test” may itself only run software from the repository form which it was built and run. But it may access “historical files” produced by tests that were run from previous versions of the software. This is made possible by saving the prior output to the test data repository and getting copies of those past files locally for the “historical test” to consume.
The default set of versions of historical files are hard-coded by the WCT developers (see waft/datarepo.py). A user may override this list at the build configure stage:
wcb configure [--test-data-versions=<versions>] [--tests] [...]
The local data repository will be populated with files during the build stage.
wcb [--tests]
Historical tests should only assume versions in this list but may also include the current version.
See the Bats topic on Creating and finding persistent files for description of the support provided for writing historical files and reading them into historical tests.
For any type of test that lacks similar support, the historical files can be found under
build/tests/history/<version>/<path...>