A "sync test" runs the test inside a testing/synctest bubble. Time moves
forward in a deterministic fashion when all goroutines are blocked
waiting for time to progress. This simplifies testing concurrent behavior.
ktesting enables writing such tests with a new SyncTest method: it can start a
new sub-test (similar to Run) or turn an existing test (typically a top-level
Test<something>) into a sync test when no new name is given.
TContext.IsSyncTest can be used to check the mode of the current test, which
may be useful in common helper code.
TContext.Wait directly maps to synctest.Wait.
This new functionality is limited to tests which use an underlying testing.T
instance.
Hiding the error in WithError is the right choice for example
when it is used inside ktesting.Eventually. Most callers probably want to deal
with the unexpected error themselves. For those who don't, WithErrorLogging
continues to log it.
The new TContext interface combines a normal context and the testing interface,
then adds some helper methods. The context gets canceled when the test is done,
but that can also be requested earlier via Cancel.
The intended usage is to pass a single `tCtx ktesting.TContext` parameter
around in all helper functions that get called by a unit or integration test.
Logging is also more useful: Log[f] and Fatal[f] output is prefixed with
"[FATAL] ERROR: " to make it stand out more from regular log output.
If this approach turns out to be useful, it could be extended further (for
example, with a per-test timeout) and might get moved to a staging repository
to enable usage of it in other staging repositories.
To allow other implementations besides testing.T and testing.B, a custom
ktesting.TB interface gets defined with the methods expected from the
actual implementation. One such implementation can be ginkgo.GinkgoT().
