Testo
A small testing utility based on the Writer monad.
npm i @opeltre/testo
Tracer Monad
The Tracer monad logs strings alongside Maybe values.
// Tracer a = Writer (Maybe a)
// ta : Tracer Int
let ta = [1, ['all', 'good']]
// tb : Tracer Int
let tb = [null, ['oops', 'no int!']]All tests return values inside the Tracer monad, e.g.
// unit : () -> Tracer Bool
let unit = () => {
let expect = 1,
obtain = someIntFunction();
return expect === obtain
? [true, ['1 = 1']],
: [false, [`1 != ${obtain}`]];
}Running tests
Each testing file exports a collection of unit tests,
which are functions to the Tracer monad.
File = {Unit}
Unit = () -> Tracer a
Units are run one by one by providing test.run
the files to be tested, e.g.
// tests.js
let test = require('@opeltre/testo');
let a = require('./fileA.js'),
b = require('./fileB.js');
test.run({a, b}); Running $ node tests.js will then log all
encountered errors if any, and provide some feedback.
Writing unit tests
The main test object exports comparison functions
to conveniently write these tests.
// fileA.js
let test = require('@opeltre/testo');
// .t1 : () -> Tracer ()
exports.t1 = () => {
let expect = [0, 1, 2],
obtain = [0, 1, 3];
return test(expect, obtain);
}
// .t2 : () -> Tracer ()
exports.t2 = () =>
let expect = {a: [0, 1]},
obtain = {a: [0, 1], b: [1, 2]};
return test(expect, obtain);
}Using with npm
Edit your package.json to:
... "test": "node tests.js"
And run $ npm test