Guide - Så gör du när du inte vill köra alla tester varje gång

Öppna package.json och lägg till skriptet
"test:only": "npx --node-options=--experimental-vm-modules jest -t" sist
bland skripten (glöm inte att lägga till ett kommatecken efter det näst sista

skriptet).

{
  "name": "assignment-a2-descriptive-statistics",
  "version": "1.2.0",
  "description": "1DV025 - Assignment A2 - Descriptive Statistics",
  "type": "module",
  "main": "src/app.js",
  "scripts": {
    "start": "node src/app.js",
    "lint": "npx eslint ./src || exit 0",
    "lint:fix": "npx eslint ./src --fix || exit 0",
    "test": "npx --node-options=--experimental-vm-modules jest || exit 0",
    "test:only": "npx --node-options=--experimental-vm-modules jest -t"
  },
  ...

Spara package.json filen.
Kör alla tester med npm test och studera resultatet. Konstatera att det
finns namn specificerade som till exempel average, argument,

exceptions. Dessa namn kan användas för att begränsa vilka tester som ska köras.

> assignment-a2-descriptive-statistics@1.2.0 test
> npx --node-options=--experimental-vm-modules jest || exit 0


(node:32892) ExperimentalWarning: VM Modules is an experimental feature. This feature could change at any time
(Use `node --trace-warnings ...` to show where the warning was created)
FAIL  test/statistics.test.js
  average
    argument
      exceptions
        × passing anything but an array should throw TypeError with the custom message 'The passed argument is not an array.' (6 ms)
        × passing an empty array should throw Error with the custom message 'The passed array contains no elements.' (2 ms)
        × passing an array containing a value that is not of the type number should throw TypeError with the custom message 'The passed array may only contain valid numbers.' (2 ms)
        × passing an array containing the value Number.NaN should throw TypeError with the custom message 'The passed array may only contain valid numbers.' (1 ms)
        × passing a large array (200000 elements) should not throw an exception (33 ms)
      side effects
        × passing [4, 2, 6, 1, 3, 7, 5, 3] should return a value and not modify the argument (1 ms)
    return value
      × passing [-2, 5, 1, 1, 5, 5, 2, -2, 2, -2] should return 1.5
      × passing [-42, -84, -2, -3] should return -32.75
...

För att köra testerna som har med average att göra kör skriptet test:only
och skicka med "average" som ett argument.
```
npm run test:only "average"
```

Enbart de tester som återfinns under namnet average kommer att köras.

> assignment-a2-descriptive-statistics@1.2.0 test:only
> npx --node-options=--experimental-vm-modules jest -t average

(node:31480) ExperimentalWarning: VM Modules is an experimental feature. This feature could change at any time
(Use `node --trace-warnings ...` to show where the warning was created)
FAIL  test/statistics.test.js
  average
    argument
      exceptions
        × passing anything but an array should throw TypeError with the custom message 'The passed argument is not an array.' (4 ms)
        × passing an empty array should throw Error with the custom message 'The passed array contains no elements.' (1 ms)
        × passing an array containing a value that is not of the type number should throw TypeError with the custom message 'The passed array may only contain valid numbers.' (1 ms)
        × passing an array containing the value Number.NaN should throw TypeError with the custom message 'The passed array may only contain valid numbers.' (1 ms)
        × passing a large array (200000 elements) should not throw an exception (30 ms)
      side effects
        × passing [4, 2, 6, 1, 3, 7, 5, 3] should return a value and not modify the argument
    return value
      × passing [-2, 5, 1, 1, 5, 5, 2, -2, 2, -2] should return 1.5
      × passing [-42, -84, -2, -3] should return -32.75
  maximum
    argument
      exceptions
        ○ skipped passing anything but an array should throw TypeError with the custom message 'The passed argument is not an array.'

<OUTPUT OMITTED FOR CLARITY!>

Test Suites: 1 failed, 1 total
Tests:       10 failed, 60 skipped, 70 total
Snapshots:   0 total
Time:        1.175 s
Ran all test suites with tests matching "average".

Vill du istället köra testerna som återfinns under namnet maximum, och
hoppa över alla andra, kör du skriptet test:only och skicka med
"maximum" som ett argument.
```
npm run test:only "maximum"
```