log4js-node/test/tap/stderrAppender-test.js

const { test } = require('tap');
const sandbox = require('@log4js-node/sandboxed-module');
const layouts = require('../../lib/layouts');

test('stderr appender', (t) => {
  const output = [];

  const appender = sandbox
    .require('../../lib/appenders/stderr', {
      globals: {
        process: {
          stderr: {
            write(data) {
              output.push(data);
            },
          },
        },
      },
    })
    .configure(
      { type: 'stderr', layout: { type: 'messagePassThrough' } },
      layouts
    );

  appender({ data: ['biscuits'] });
  t.plan(2);
  t.equal(output.length, 1, 'There should be one message.');
  t.equal(output[0], 'biscuits\n', 'The message should be biscuits.');
  t.end();
});

test('stderr appender with default layout', (t) => {
  const output = [];
  layouts.colouredLayout = () => 'I used the colouredLayout';

  const appender = sandbox
    .require('../../lib/appenders/stderr', {
      globals: {
        process: {
          stderr: {
            write(data) {
              output.push(data);
            },
          },
        },
      },
    })
    .configure({ type: 'stderr' }, layouts);

  appender({ data: ['biscuits'] });
  t.plan(2);
  t.equal(output.length, 1, 'There should be one message.');
  t.equal(
    output[0],
    'I used the colouredLayout\n',
    'The message should have gone through the default layout.'
  );
  t.end();
});