avajs/ava

Print warning when test files take a disproportionate amount of time to declare tests

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#2565 opened on Aug 22, 2020

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 (2 comments) (4 reactions) (1 assignee)JavaScript (20,600 stars) (1,408 forks)batch import
help wantedscope:reportersscope:scheduling

Description

Based on feedback from @shusson in https://github.com/avajs/ava/issues/2268#issuecomment-676513972 it would be interesting if we could instrument how long it takes between AVA loading the test file to tests being declared.

This time is not taken by AVA itself, but instead by the test and project code. There are likely optimizations possible in the project that is using AVA.

If this takes a disproportionate amount of time of the overall test run (5%? 10%?) we should print a warning after the test run has completed.

Contributor guide

Tech stack
javascriptnodejs
Domain
testingperformance
Issue type
feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
half day
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
mostly clear
Prerequisites
Basic understanding of AVA internalsNode.js timing APIs
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
55
Research direction
Examine the test loading workflow in AVA, specifically the `lib/runner.js` or similar files that handle test declaration. Look at how long it takes from loading a test file to the first test declaration. Use `performance.now()` or similar to measure durations and compare to total test run time. Check existing comments on issue #2268 for context. The warning should be printed after the test run completes if the loading time exceeds a threshold like 5% or 10% of total time.