Wrong line number shown for failing assert

[ratiotile]

Description

AVA reports the wrong line number on failing tests. It seems that sourcemaps aren't working, as the line number is greater than the size of the test file. When the line number falls within the source file, a snippet is displayed, but it does not correspond with the failing assertion.

Test Source

import test from 'ava'
import * as convert from './parameter_convert.js'

test('int converter', t => {
  let converted = convert.to.int('foo')
  t.is(converted, 'foo')
})

Error Message & Stack Trace

The test file is only 7 lines long, yet the line 40 is indicated in the message below:

middleware › test_parameter_convert › int converter

test_parameter_convert.js:40

  Difference:

  - NaN
  + 'foo'

Config

I am using ava.config.js:

export default {
  files: ['src/**/test_*.js'],
  sources: ['src/**/*.js'],
  color: true,
  compileEnhancements: false,
  require: ['./babel_register.js'],
  verbose: true,
}

.babelrc

module.exports = function(api) {
  let config = {
    sourceMaps: 'inline',
    presets: [
      '@babel/preset-flow',
      [
        '@babel/preset-env',
        {
          targets: {
            node: 'current',
          },
          modules: 'commonjs',
        },
      ],
    ],
  api.cache.forever()
  return config
}

Command-Line Arguments

ava

Relevant Links

Minimal reproduction
parameter_convert.js

// @flow
/**
 * Conversion functions
 */
export const to = {
  string: (raw: any) => String(raw),
  date: (raw: any) => new Date(raw),
  int: (raw: any) => {
    const converted = Number(raw)
    return converted === undefined ? raw : converted
  },
}

Environment

darwin 17.7.0
ava 1.0.0-rc.2
npm 6.4.1

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[ratiotile]

Updated with minimal reproduction
edit: This seems to be a regression. AVA 0.25.0 doesn't have this behavior.
edit2: AVA 0.25.0 shows the correct line for a failing assert, but the wrong line in the code under test.

[novemberborn]

Could you try configuring @babel/register so it ignores the test files? See the last example in https://github.com/avajs/ava/blob/master/docs/recipes/babel.md#compile-sources.

I suspect the double compilation may be causing trouble. Perhaps AVA loads its internal source map and the one from @babel/register is ignored. Or perhaps both @babel/register and AVA are trying to set up source map handling and it's failing… unfortunately this stuff is really hard to get right.

[ratiotile]

I followed the docs and tried to configure @babel/register

1. ignore: ['src/test_*'] doesn't work
2. ignore: ['src/test_parameter_convert.js'] works. Maybe wildcards are broken?
3. ignore: [/src\/test_.*\.js/] the ignore items must be regex.

Seems that the docs are wrong about how to configure @babel/register. Would you accept a PR on the docs?

[ratiotile]

Errors in the source file are still reported on the wrong line (a failing assert in the test file is correctly reported). I tried disabling sourceMaps in babel/register, but it still doesn't work.

[novemberborn]

1. ignore: ['src/test_*'] doesn't work

That may need a file extension.

Seems that the docs are wrong about how to configure @babel/register. Would you accept a PR on the docs?

Always!

Errors in the source file are still reported on the wrong line (a failing assert in the test file is correctly reported). I tried disabling sourceMaps in babel/register, but it still doesn't work.

OK. It may be a little while until I have time to look into this further.

[ratiotile]

The workaround I've found is to disable AVA's builtin babel transpilation with compileEnhancements: false, babel: false and rely on babel/register to do it by with the configuration:

require('@babel/register')({
  ignore: [
    /node_modules/,
    /build\//,
    /coverage\//,
  ],
  inputSourceMap: true,
  plugins: [
    [
      'istanbul',
      {
        all: true,
        cache: true,
        exclude: ['**/test_*.js', 'src/functional_tests/*'],
        include: ['src/**/*.js'],
      },
    ],
  ],
  presets: ['@ava/transform-test-files'],
})

@babel/register requires that the ignore paths are regex expressions and not strings.

Now the reported line numbers of errors are correct both in test files and source files.

[klarkc]

Happening to me with this config:

{
"ava": {
    "require": [
      "esm"
    ],
    "babel": false,
    "extensions": [
      "mjs"
    ]
  },
}

[kaelzhang]

The issue always reproduces when package.json.ava.babel: false that I use in every project, which drives me mad.

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[razvangherghina]

Just add retainLines: true in babel configuration under sourceMaps: 'inline' and the correct line is shown. no PR added :).

[novemberborn]

I think this is a source map problem. #2474 could be a solution.