[PWA-1002] Increase Test Coverage in venia-ui/lib/components/CheckoutPage

[tjwiebell]

Description

As part of our initiative to increase test coverage, stability and confidence in our project we've identified this folder as having a lower than acceptable level of test coverage.

Acceptance Criteria:

Increase test coverage to an acceptable level, ideally 100%

Implementation Note

There was a component in here brainTreeDropIn that I didn't feel comfortable trying to cover. It relied on a lot of waterfall async work to render that wasn't straight forward, so might be better to tap on the original develop for covering that file. Could also be an opportunity to re-visit and see if patterns we've started coalescing on could be added to this component to help simplify.

Related Issue

• [PWA-1002] Increase Test Coverage in venia-ui/lib/components/CheckoutPage

Acceptance

Verification Stakeholders

Specification

Verification Steps

1. Run tests locally or look at Coveralls reports
2. Verify that CheckoutPage, OrderSummary, and PriceAdjustments coverage improved

Screenshots / Screen Captures (if appropriate)

Checklist

• I have added tests to cover my changes, if necessary.
• I have added translations for new strings, if necessary.
• I have updated the documentation accordingly, if necessary.

[tjwiebell]

I did this after discussions from peer review; that our components would benefit from more manual mocks. Would like to discuss this further, but provided manual mocks like these is pretty simple, but not necessary.

[tjwiebell]

I may have stumbled onto why we haven't embraced this more. It seems some very old Jest bug causes these duplicate mock warnings, because jest-haste-map stores these mocks by name and not by path. Given we're a project where we use index files to export public API, I can see how this warning may have scared us away from manual mocks, since all of these module names would be index.

I'm digging for a solution, but nothing seems to be working. As you can see, the tests function fine, there's just this very in your face warning you get the first time you run the suite. We could mock underlying components instead of index exports, but expect we'd run into a similar issue eventually.

Original Bug: jestjs/jest#2070
The warning:

jest-haste-map: duplicate manual mock found: index
  The following files share their name; please delete one of them:
    * <rootDir>/packages/peregrine/lib/RestApi/__mocks__/index.js
    * <rootDir>/packages/venia-ui/lib/components/Accordion/__mocks__/index.js

[tjwiebell]

Went ahead and just pulled this out, can disregard.

[PWAStudioBot]

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📖	Associated JIRA tickets: PWA-1002.
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[sirugh]

I haven't looked, but I really hope there aren't too many conflicts with #2969