Run one test code with varying inputs to minimise on repition, and maximise on ease of test creation. More tests mean better coverage.
npm install jest-theories
import theoretically from 'jest-theories';
describe('NumberToLongString', () => {
const theories = [
{input: 100, expected: 'One hundred'},
{input: 1000, expected: 'One thousand'},
{input: 10000, expected: 'Ten thousand'},
{input: 100000, expected: 'One hundred thousand'},
]
theoretically('the number {input} is correctly translated to string', theories, theory => {
const output = NumberToLongString(theory.input);
expect(output).toBe(theory.expected);
})
});
`
The input string uses string-format for formatting.
Additionally to the fields available in your theory you can also use $idx for the index of the theory and $no for the number of the theory.
If you want to do more complex test name creation you can supply a function which takes the parameters of the theory and the index
`
import theoretically from 'jest-theories';
describe('Bigger than 1000', () => {
const theories = [
{input: 100, expected: false},
{input: 1000, expected: false},
{input: 10000, expected: true},
{input: 100000, expected: true},
]
theoretically(({input, expected}) => the number ${input} is ${expected ? '' : 'not'} bigger than 1000, theories, theory => {
const output = IsBiggerThan1000(theory.input);
expect(output).toBe(theory.expected);
})
});
``