Display jest warning as a warning in the Azure DevOps pipeline build results page

Question

We have an Azure DevOps pipeline which uses self hosted Windows agents with Azure DevOps server 2019. The pipeline runs our front-end tests. For this we use the following command line to run the tests: npm run jest -- --ci --reporters=default --reporters=jest-junit. Then we use the publish test results task to publish the results.

This all works just fine. However, we noticed recently that the runtime warnings in the tests aren't being displayed anywhere. We have our linter warnings displayed in the build results page by adding the vso formatter like this: npm run nx run-many -- --target="lint" --all --skip-nx-cache=true --parallel --format=vso. However, it doesn't seem jest has any kind of format argument we can use.

Is it possible to take the warnings that display in the jest tests and log them in the results page of the build? Thank you for any help, please let me know if I can provide additional information.

Answer 1

So I ended up using the following PowerShell task to append a version of what @PerryQian-MSFT posted into my jest-setup.js file.

- task: PowerShell@2
  displayName: Make test log warnings
  inputs:
    targetType: 'inline'
    script: |
      Add-Content -path config/jest-setup.js -value @"
        import { command, log } from "azure-pipelines-logging";
        const { error, warn } = console;

        global.console.error = (...args) => {
          error(...args);
          log(command("task", "logissue", { type: "error" })(...args));
        };
        global.console.warn = (...args) => {
          warn(...args);
          log(command("task", "logissue", { type: "warning" })(...args));
        };
      "@

I had to change the solution from the GitHub post because I didn't want the tests to fail if they hit a warning, the pipeline should still succeed, just with issues. To fix this I included azure-pipelines-logging as a dependency. Then I was able to use log(command("task", "logissue", { type: "warning" })(...args)); to log in the pipeline whenever a warning is called.