This project is a standalone binary but does not use the typical pattern of a
package named main with a function named main. Instead, it uses a test file,
runner_test.go, which implements TestMain with functionality, not all
related to running tests. This provides a testing.T which can be passed to
the TCK, so it can use the Go test framework, for example to provide output of
each test case.
An alternative that would use the more idiomatic main package could
be used by setting up the testing framework manually. However, Go does not
provide a clear mechanism for doing this. testing.Main is documented as
being legacy and systems should be updated to testing.MainStart.
testing.MainStart is documented as not meaning to be called directly.
Implementing TestMain and compiling our binary with go test -c gives us
the functionality we need without relying on any internal or questionably
supported mechanisms.