jestjs/jest

Allow buffering console when running a single test

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#6,441 opened on Jun 11, 2018

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Description

🐛 Bug Report

Splitting this from this issue: https://github.com/facebook/jest/issues/4156#issuecomment-395848216

In scenarios involving running multiple tests, console output is buffered and can be intercepted by a test reporter. When only a single test runs, the output is never buffered. This behavior is mentioned here: https://github.com/facebook/jest/issues/2080

To Reproduce

Initiate a test run that matches only a single test.

Expected behavior

In a reporter, TestResult.console should be populated for all test run scenarios (at least optionally).

Run npx envinfo --preset jest

Paste the results here:

  System:
    OS: macOS High Sierra 10.13.5
    CPU: x64 Intel(R) Core(TM) i7-7920HQ CPU @ 3.10GHz
  Binaries:
    Node: 8.9.4 - ~/.nvm/versions/node/v8.9.4/bin/node
    Yarn: 1.6.0 - /usr/local/bin/yarn
    npm: 5.6.0 - ~/.nvm/versions/node/v8.9.4/bin/npm
  npmPackages:
    @types/jest: 22.2.3 => 22.2.3
    jest: =23.1.0 => 23.1.0

Contributor guide

Tech stack
javascripttypescript
Domain
testing
Issue type
bug
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.
1-2 days
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.
clear
Prerequisites
Familiarity with JestNode.jsJavaScript
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
40
Research direction
The issue requires investigating how Jest buffers console output during test runs. Look into the test runner logic, possibly in packages/jest core, specifically how it handles single vs multiple test runs. The discussion in issue #4156 and #2080 provides context. The deliverable is to ensure TestResult.console is populated for single test runs, potentially by updating the buffering logic in the reporter or runner.