Kong 1.0 rc3 Postgres migrations failing in custom tests

[mars]

This issue is similar in context to #4031, but a different issue.

Summary

When running custom tests with a Postgres backend in this Kong app (uses the spec/helpers.lua & a bin/busted runner modeled after the one in Kong master), the tests error.

Locally these tests work with a local Postgres database (solved in #4031), but fail in this different way when run by Heroku CI tests with hosted, cloud Postgres:

$ bin/test -o gtest -v
[==========] Running tests from scanned files.
[----------] Global test environment setup.
[----------] Running tests from spec/integration/kong/plugins/hello-world-header_spec.lua
2018/11/28 23:39:25 [warn] 2876#0: *2 [lua] connector.lua:196: setkeepalive(): unable to close postgres connection, context: ngx.timer
2018/11/28 23:39:25 [warn] 2876#0: *2 [lua] connector.lua:196: setkeepalive(): unable to close postgres connection, context: ngx.timer
./spec/helpers.lua:156: [postgres error] Error during migration 2016-05-04-160000_resp_trans_schema_changes: [postgres] ERROR: column "run_on" does not exist (154)
stack traceback:
	./spec/helpers.lua:156: in function 'get_db_utils'
	spec/integration/kong/plugins/hello-world-header_spec.lua:11: in function <spec/integration/kong/plugins/hello-world-header_spec.lua:10>
[----------] 0 tests from spec/integration/kong/plugins/hello-world-header_spec.lua (3966.10 ms total)

I've confirmed that the database is empty before the tests run.

Why would these test migrations fail like this?

Steps To Reproduce

1. Deploy to Heroku a Kong app from this commit (in the kong-1.0 branch)
2. Add the app to a new Heroku Pipeline
3. Connect the Pipeline with your own GitHub fork of heroku-kong
4. Enable Tests in the Pipeline
5. Start a new test on the kong-1.0 branch
6. Watch the test fail

Additional Details & Logs

• Kong version 1.0.0rc3
• Operating system Heroku-18 (Ubuntu 18.04)

[mars]

This is no longer an issue, after updating to Kong master (1.0.0rc4 plus a few more commits leading up to 1.0.0), and also updating our custom integration specs to follow Kong's new integration spec usage patterns/signatures.