document assert usage standards for contributors

[jeremylt]

Describe the Issue

In this PR it was mentioned that assert.isTrue() is preferred over assert() in our codebase.

This should be documented somewhere if this is our standard. Also, a lot of the curriculum tests don't use this, so it would be worth making an issue to have someone go change everywhere we missed this standard.

Affected Page

https://contribute.freecodecamp.org/#/codebase-best-practices

Your code

N/A

Expected behavior

Documentation should state standards.

Screenshots

No response

System

All

Additional context

No response

[lasjorg]

I wouldn't say this is specific to that, or any, assert method. If a method exists that expresses what is tested for, we should prefer it.

A lot of the assert method can be replaced with just assert(expression) but the point of using the methods is both in readability and implementation.

1. Using the proper method makes it clear what is expected.

2. We should prefer the internal testing library implementation.

assert(Array.isArray([]), 'empty arrays are arrays');
assert.isArray([], 'empty arrays are arrays');

3. The test should express what is being tested for instead of relying on the assert message.

---

Edit: I am not suggesting we have to replace all assert(true === true) with assert.isTrue(true === true) but if a test is using that method I see no point in changing it to assert(true === true).

I don't think we have to enforce the use of isTrue but I would still prefer it to assert(expression)

[ShaunSHamilton]

Some context: freeCodeCamp/freeCodeCamp#43105 (comment)

I have been advocating for using the specific assertions, because the default assertion messages can be very helpful: freeCodeCamp/freeCodeCamp#40518

We mostly¹ do not use them, but I have always hoped we would in the future.

Footnotes

1. In some of the backend challenges, we output the assertion messages to the browser console, and I have frequently used this to debug failed tests when helping Campers on the forum: https://forum.freecodecamp.org/t/help-with-issue-tracker-project/433239/3 ↩

[a2937]

Would the documentation for the assertion methods would go on this page? https://contribute.freecodecamp.org/#/how-to-work-on-coding-challenges?id=writing-tests