Chai Immutable

This provide a set of Chai assertions for Facebook's Immutable library for JavaScript collections.

Installation

Install via npm:

npm install chai-immutable

You can then use this plugin as any other Chai plugins:

var chai = require('chai');
var chaiImmutable = require('chai-immutable');

chai.use(chaiImmutable);

BDD API Reference

.empty

Asserts that the immutable collection is empty.

expect(List()).to.be.empty;
expect(List.of(1, 2, 3)).to.not.be.empty;

.equal(collection)

• @param { Collection } collection

Asserts that the values of the target are equvalent to the values of collection. Aliases of Chai's original equal method are also supported.

var a = List.of(1, 2, 3);
var b = List.of(1, 2, 3);
expect(a).to.equal(b);

.include(value)

• @param { Mixed } val

The include and contain assertions can be used as either property based language chains or as methods to assert the inclusion of a value in an immutable collection. When used as language chains, they toggle the contains flag for the keys assertion.

expect(new List([1, 2, 3])).to.include(2);
expect(new Map({ foo: 'bar', hello: 'universe' })).to.include.keys('foo');

.keys(key1[, key2, ...[, keyN]])

• @param { String... | Array | Object | Collection } keyN

Asserts that the keyed collection contains any or all of the passed-in keys. Use in combination with any, all, contains, or have will affect what will pass.

When used in conjunction with any, at least one key that is passed in must exist in the target object. This is regardless whether or not the have or contain qualifiers are used. Note, either any or all should be used in the assertion. If neither are used, the assertion is defaulted to all.

When both all and contain are used, the target object must have at least all of the passed-in keys but may have more keys not listed.

When both all and have are used, the target object must both contain all of the passed-in keys AND the number of keys in the target object must match the number of keys passed in (in other words, a target object must have all and only all of the passed-in keys).

key is an alias to keys.

expect(new Map({ foo: 1 })).to.have.key('foo');
expect(new Map({ foo: 1, bar: 2 })).to.have.keys('foo', 'bar');
expect(new Map({ foo: 1, bar: 2 })).to.have.keys(new List(['bar', 'foo']));
expect(new Map({ foo: 1, bar: 2 })).to.have.keys(new Set(['bar', 'foo']));
expect(new Map({ foo: 1, bar: 2 })).to.have.keys(new Stack(['bar', 'foo']));
expect(new Map({ foo: 1, bar: 2 })).to.have.keys(['bar', 'foo']);
expect(new Map({ foo: 1, bar: 2 })).to.have.keys({ 'bar': 6, 'foo': 7 });
expect(new Map({ foo: 1, bar: 2 })).to.have.keys(new Map({ 'bar': 6, 'foo': 7 }));
expect(new Map({ foo: 1, bar: 2 })).to.have.any.keys('foo', 'not-foo');
expect(new Map({ foo: 1, bar: 2 })).to.have.all.keys('foo', 'bar');
expect(new Map({ foo: 1, bar: 2 })).to.contain.key('foo');

.size(value)

• @param { Number } size

Asserts that the immutable collection has the expected size.

expect(List.of(1, 2, 3)).to.have.size(3);

It can also be used as a chain precursor to a value comparison for the size property.

expect(List.of(1, 2, 3)).to.have.size.least(3);
expect(List.of(1, 2, 3)).to.have.size.most(3);
expect(List.of(1, 2, 3)).to.have.size.above(2);
expect(List.of(1, 2, 3)).to.have.size.below(4);
expect(List.of(1, 2, 3)).to.have.size.within(2,4);

Similarly to length/lengthOf, sizeOf is an alias of size:

expect(List.of(1, 2, 3)).to.have.sizeOf(3);

TDD API Reference

.equal(actual, expected)

• @param {Collection} actual
• @param {Collection} expected

Asserts that the values of the target are equvalent to the values of collection. Note that .strictEqual and .deepEqual assert exactly like .equal in the context of Immutable data structures.

var a = List.of(1, 2, 3);
var b = List.of(1, 2, 3);
assert.equal(a, b);

.sizeOf(collection, length)

• @param {Collection} collection
• @param {Number} size

Asserts that the immutable collection has the expected size.

assert.sizeOf(List.of(1, 2, 3), 3);
assert.sizeOf(new List(), 0);