rollup-plugin-power-assert

Rollup plugin for power-assert: Provides descriptive assertion messages through standard assert interface. No API is the best API.

Note that rollup-plugin-power-assert also supports Vitest's assert API.

 FAIL  examples/__tests__/demo.test.mts > power-assert demo > Destructuring and TemplateLiteral
AssertionError:

assert(`${alice.name} and ${bob.name}` === `bob and alice`)
       |  |     |           |   |      |   |
       |  |     |           |   |      |   "bob and alice"
       |  |     |           |   |      false
       |  |     |           |   "bob"
       |  |     |           Object{name:"bob"}
       |  |     "alice"
       |  Object{name:"alice"}
       "alice and bob"

"alice and bob" === "bob and alice"


- Expected
+ Received

- bob and alice
+ alice and bob

INSTALL

$ npm install --save-dev rollup-plugin-power-assert

USAGE

Vite/Vitest usage and example

For given test file examples/__tests__/demo.test.mts below,

import { describe, it, assert } from 'vitest';

describe('power-assert demo', () => {
  it('Array#indexOf', () => {
    const ary = [0,1,2];
    const zero = 0;
    const two = 2;
    assert(ary.indexOf(zero) === two);
  });

  it('Destructuring and TemplateLiteral', () => {
    let [alice, bob] = [ { name: 'alice' }, { name: 'bob' } ];
    assert(`${alice.name} and ${bob.name}` === `bob and alice`);
  });
});

Create a vite.config.js configuration file and import the plugin:

import { defineConfig } from 'vite';
import { powerAssert } from 'rollup-plugin-power-assert';
const testPattern = 'examples/**/__tests__/**/*.test.mts';

export default defineConfig({
  plugins: [
    powerAssert({
      include: testPattern,
    }),
  ],
  test: {
    include: testPattern,
    // ...
  },
});

Run vitest run. You will see the power-assert output appears.

> vitest run

 ❯ examples/__tests__/demo.test.mts (2)
   ❯ power-assert demo (2)
     × Array#indexOf
     × Destructuring and TemplateLiteral

⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯ Failed Tests 2 ⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯

 FAIL  examples/__tests__/demo.test.mts > power-assert demo > Array#indexOf
AssertionError:

assert(ary.indexOf(zero) === two)
       |   |       |     |   |
       |   |       |     |   2
       |   |       |     false
       |   |       0
       |   0
       [0,1,2]

0 === 2


- Expected
+ Received

- 2
+ 0

 ❯ examples/__tests__/demo.test.mts:8:5
      6|     const zero = 0;
      7|     const two = 2;
      8|     assert(ary.indexOf(zero) === two);
       |     ^
      9|   });
     10|

⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯[1/2]⎯

 FAIL  examples/__tests__/demo.test.mts > power-assert demo > Destructuring and TemplateLiteral
AssertionError:

assert(`${alice.name} and ${bob.name}` === `bob and alice`)
       |  |     |           |   |      |   |
       |  |     |           |   |      |   "bob and alice"
       |  |     |           |   |      false
       |  |     |           |   "bob"
       |  |     |           Object{name:"bob"}
       |  |     "alice"
       |  Object{name:"alice"}
       "alice and bob"

"alice and bob" === "bob and alice"


- Expected
+ Received

- bob and alice
+ alice and bob

 ❯ examples/__tests__/demo.test.mts:13:5
     11|   it('Destructuring and TemplateLiteral', () => {
     12|     let [alice, bob] = [ { name: 'alice' }, { name: 'bob' } ];
     13|     assert(`${alice.name} and ${bob.name}` === `bob and alice`);
       |     ^
     14|   });
     15| });

⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯[2/2]⎯

 Test Files  1 failed (1)
      Tests  2 failed (2)
   Start at  17:16:32
   Duration  198ms (transform 58ms, setup 0ms, collect 52ms, tests 6ms, environment 0ms, prepare 42ms)

Rollup usage

Create a rollup.config.js configuration file and import the plugin:

import { globSync } from 'glob';
import { powerAssert } from 'rollup-plugin-power-assert';

export default {
  input: globSync('**/*.mjs'),
  plugins: [
    powerAssert({
      include: ['**/*.test.mjs']
    })
  ]
};

Then call rollup either via the CLI or the API.

OPTIONS

include

Type: String | RegExp | Array[...String|RegExp] Default: [] Example: include: '**/__tests__/**/*test.js',

A pattern, or array of patterns, which specify the files in the build the plugin should operate on.

exclude

Type: String | RegExp | Array[...String|RegExp] Default: []

A pattern, or array of patterns, which specify the files in the build the plugin should ignore.

AUTHOR

• Takuto Wada

LICENSE

Licensed under the MIT license.