chai-bignumber

!Build Status

Chai assertions for comparing arbitrary-precision decimals using the bignumber.js library.

Installation

``bash
npm install --save-dev chai-bignumber
`

Usage

`javascript
var chai = require('chai');

//use default BigNumber
chai.use(require('chai-bignumber')());

//use custom BigNumber
chai.use(require('chai-bignumber')(BigNumber));
`

Assertions

The following assertion methods are provided and will override the existing
builtin assertions if the bignumber property is explicitly set as part of
the assertion chain:
- equal/equals/eq
- above/gt/greaterThan
- least/gte/greaterThanOrEqual
- below/lt/lessThan
- most/lte/lessThanOrEqual

The above methods have the following signature: (value, dp, rm).
Where dp is an optional argument which specifies the number of decimal places
to round each side of the comparison to (values are not rounded by default),
while rm is an optional argument which specifies the
rounding mode
as supported by bignumber.js (defaults to BigNumber.ROUND_HALF_UP).

A set of additional assertion properties is also provided:
- finite
- integer
- negative
- zero

Values can be instances of number, BigNumber or string which can be
converted into a valid number. Only BDD style (expect or should) assertions
are supported.

Examples

Methods:

`javascript
var result = new BigNumber('100000000000000000').plus(1);
var expected = '100000000000000001';
result.should.be.bignumber.equal(expected);
expect(result).to.be.bignumber.at.most(expected);
'1000'.should.be.bignumber.lessThan(2000);
`

Methods with rounding:

`javascript
var BigNumber = require('bignumber.js');
(100.343).should.be.bignumber.equal(100.341, 2);
(100.349).should.be.bignumber.equal(100.341, 2, BigNumber.ROUND_DOWN);
`

Properties:

`javascript
(100 / 0).should.not.be.finite;
expect(10).to.be.integer;
(-100).should.be.negative;
expect(1 - 1).to.be.zero;
``

License

MIT