Go 1.9 adds this new function which, when called, marks the caller as
being a "helper function". Helper function stack frames are then skipped
when trying to find a line of test code to blame for a test failure, so
that the code in the main test function appears in the test failure output
rather than a line within the helper function itself.
This covers many -- but probaly not all -- of our test helpers across
various packages.
Previously we had no automated testing of whether we can produce a
Terraform executable that actually works. Our various functional tests
have good coverage of specific Terraform features and whole operations,
but we lacked end-to-end testing of actual usage of the generated binary,
without any stubbing.
This package is intended as a vehicle for such end-to-end testing. When
run normally under "go test" it will produce a build of the main Terraform
binary and make it available for tests to execute. The harness exposes
a flag for whether tests are allowed to reach out to external network
services, controlled with our standard TF_ACC environment variable, so
that basic local tests can be safely run as part of "make test" while
more elaborate tests can be run easily when desired.
It also provides a separate mode of operation where the included script
make-archive.sh can be used to produce a self-contained test archive that
can be copied to another system to run the tests there. This is intended
to allow testing of cross-compiled binaries, by shipping them over to
the target OS and architecture to run without requiring a full Go compiler
installation on the target system.
The goal here is not to test again functionality that's already
well-covered by our existing tests, but rather to test chains of normal
operations against the build binary that are not otherwise tested
together.
Martin Atkins