Trigger unit tests for docker images upload workflow

[xibinliu]

Description

• images will only be tagged to the current date when unit tests pass
• Images will only be tagged to "latest" when unit tests pass

Tests

See this manually triggered workflow run

Old:
Another old workflow run - by calling tests from another file.

Checklist

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[SurbhiJainUSC]

What is the use case for this?

[xibinliu]

This is to keep the images generated by this workflow development tests in another image repo so the formal image repo is not polluted.
(our previous discussion: For testing purposes, can you change the name of the docker image so that it doesn't pollute our production images.)

[xibinliu]

@SurbhiJainUSC we need to discuss what tags do we want to add to the images before and after testing.

Current:

• before tests: ${{ github.run_id }}, and hashes of the repos
• after tests: "latest", and "<image_date>"

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

📢 Thoughts on this report? Let us know!

[SurbhiJainUSC]

Why do we need a different workflow for testing the docker image?

Can we update build_and_push_docker_image.yml to something like this:

# https://github.com/AI-Hypercomputer/maxtext/blob/main/.github/workflows/build_and_push_docker_image.yml#L111
- name: Build and push Docker image

# Runs tests on docker image with tag as ${{ github.run_id }}
- name: Test Dokcer Image

# [Add tags such as ](https://github.com/AI-Hypercomputer/maxtext/blob/main/.github/workflows/build_and_push_docker_image.yml#L129)
- name: Add tags to Docker Image

[xibinliu]

Merged the jobs into build_and_push_docker_image.yml and now tests are executed immediately after the image has been pushed.

One caveat: since the tpu-post-training-nightly depends on tpu-post-training-stable, the whole workflow needs more time to finish because it now waits for the test to be done.