We now test back-compat with "ant test-tag", which is very useful for
catching breaks in back compat before committing.
However, that currently checks out "src/test" sources and then
compiles them against the trunk JAR, and runs the tests. Whereas our
back compat policy:
states that no recompilation is required on upgrading to a new JAR.
Ie you should be able to drop in the new JAR in place of your old one
and things should work fine.
So... we should fix "ant test-tag" to:
- Do full checkout of core sources & tests from the back-compat-tag
- Compile the JAR from the back-compat sources
- Compile the tests against that back-compat JAR
- Swap in the trunk JAR
- Run the tests