test-mixer^1.0.1

Test helper to generate function opts object variations

Install via npm

npm i test-mixer

The default is exported, so instead of mixer below, you can name the consumed function however you want.

Consume via a require():

const mixer = require("test-mixer");

or as an ES Module:

import mixer from "test-mixer";

Install as a script, via CDN

Put this in your HTML:

<script src="https://cdn.jsdelivr.net/npm/test-mixer/dist/test-mixer.umd.js">

Then, you’ll get a global variable testMixer in your Global object and you consume it like this:

const mixer = testMixer;

This mixer is your main function. See its API in the main section.

Trivia

This program has 18 assertions in its unit tests. That's less than all unit test assertions' median (50) and less than geometric mean (70).

§ Quick Take

import { strict as assert } from "assert";
import mixer from "test-mixer";

// generates 2^n combinations
assert.deepEqual(
  mixer(
    {
      foo: true, // override
      baz: 1, // not a boolean
    },
    {
      // defaults or reference object:
      foo: true,
      bar: false,
      baz: 0, // default is not a boolean either
    }
  ),
  [
    {
      foo: true, // static, as per 1st arg
      bar: false, // combination #1
      baz: 1, // non-bools get copied over
    },
    {
      foo: true, // static, as per 1st arg
      bar: true, // combination #2
      baz: 1, // non-bools get copied over
    },
  ]
);

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§ Purpose

It's used to generate an array of all possible combinations of options object boolean settings.

detergent has 12 boolean toggles — that's 2^12 = 4096 variations to test for each input.

string-collapse-white-space has 6 boolean toggles — that's 2^6 = 64 variations to test for each input.

And so on.

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§ API - Input

mixer(
  objWithFixedKeys,
  [defaultsObj]
)

In other words, it's a function which takes two input arguments, second one being optional (marked by square brackets).

Input argument	Type	Obligatory?	Description
`objWithFixedKeys`	Plain object	yes, but can be empty	Object with boolean keys that should not be used to generate variations.
`defaultsObj`	Plain object	yes, can be empty, should be a superset of `objWithFixedKeys`	Put the default options object here.

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§ API - Output

Program returns an array of zero or plain objects.

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§ In practice

Let's say, we test detergent. It has the following default opts defaultOpts in the source :

{
  fixBrokenEntities: true,
  removeWidows: true,
  convertEntities: true,
  convertDashes: true,
  convertApostrophes: true,
  replaceLineBreaks: true,
  removeLineBreaks: false,
  useXHTML: true,
  dontEncodeNonLatin: true,
  addMissingSpaces: true,
  convertDotsToEllipsis: true,
  stripHtml: true,
  eol: "lf",
  stripHtmlButIgnoreTags: ["b", "strong", "i", "em", "br", "sup"],
  stripHtmlAddNewLine: ["li", "/ul"],
  cb: null,
}

Imagine, we're testing how detergent strips HTML, setting, opts.stripHtml.

// 😱 eleven other boolean opts settings were left out, 4095 other combinations!
import tap from "tap";
const { det } = require("detergent");
tap.test(`01`, (t) => {
  t.equal(
    det(t, n, `text <a>text</a> text`, {
      stripHtml: true,
    }).res,
    "text text text"
  );
  t.end();
});

Here's the proper way:

// ✅
import tap from "tap";
const { det, opts } = require("detergent");
import testMixer from "text-mixer";

// we create a wrapper to skip writing the second input argument again and again
const mixer = (ref) => testMixer(ref, opts);

tap.test(`01`, (t) => {
  mixer({
    stripHtml: false, // <--- pinned setting
  }).forEach((opt, n) => {
    t.equal(
      det(t, n, `text <a>text</a> text`, opt).res,
      `text <a>text</a> text`,
      JSON.stringify(opt, null, 4)
    );
  });
  mixer({
    stripHtml: true, // <--- pinned setting
  }).forEach((opt, n) => {
    t.equal(
      det(t, n, `text <a>text</a> text`, opt).res,
      `text text text`,
      JSON.stringify(opt, null, 4)
    );
  });
  t.end();
});

Above, we assert that on all 2^11=2048 setting variations where opts.stripHtml === false, input text <a>text</a> text yields text <a>text</a> text.

Then, we assert that with setting opts.stripHtml === true, tags are stripped, in all other 2^11=2048 possible setting combinations.

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