Chai assertions for comparing arbitrary-precision decimals using the bignumber.js library
npm install chai-bignumberChai assertions for comparing arbitrary-precision decimals using the bignumber.js library.
``bash`
npm install --save-dev chai-bignumber
`javascript
var chai = require('chai');
//use default BigNumber
chai.use(require('chai-bignumber')());
//use custom BigNumber
chai.use(require('chai-bignumber')(BigNumber));
`
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).dp
Where is an optional argument which specifies the number of decimal placesrm
to round each side of the comparison to (values are not rounded by default),
while is an optional argument which specifies thebignumber.js
rounding mode
as supported by (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 beexpect
converted into a valid number. Only BDD style ( or should) assertions
are supported.
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;