A parameterised testing library for Jest inspired by mocha-each.
jest-each allows you to provide multiple arguments to your test/describe which results in the test/suite being run once per row of parameters.
.test to runs multiple tests with parameterised data.it.test.only to only run the parameterised tests.it.only or .fit.test.skip to skip the parameterised tests.it.skip or .xit or .xtest.test.concurrent.it.concurrent.test.concurrent.only.it.concurrent.only.test.concurrent.skip.it.concurrent.skip.describe to runs test suites with parameterised data.describe.only to only run the parameterised suite of tests.fdescribe.describe.skip to skip the parameterised suite of tests.xdescribedoneprintf formatting:%p - pretty-format.%s- String.%d- Number.%i - Integer.%f - Floating point value.%j - JSON.%o - Object.%# - Index of the test case.%% - single percent sign ('%'). This does not consume an argument.
.test
.test with Tagged Template Literals
.describe
npm i --save-dev jest-each
yarn add -D jest-each
jest-each is a default export so it can be imported with whatever name you like.
js
// es6
import each from 'jest-each';
js
// es5
const each = require('jest-each').default;
each([parameters]).test(name, testFn)each:Array of Arrays with the arguments that are passed into the testFn for each row[1, 2, 3] -> [[1], [2], [3]].test:String the title of the test.printf formatting:%p - pretty-format.%s- String.%d- Number.%i - Integer.%f - Floating point value.%j - JSON.%o - Object.%# - Index of the test case.%% - single percent sign ('%'). This does not consume an argument.$variable$variable.path.to.value$# to inject the index of the test case$variable with the printf formatting except for %%Function the test logic, this is the function that will receive the parameters of each row as function argumentseach([parameters]).describe(name, suiteFn)each:Array of Arrays with the arguments that are passed into the suiteFn for each row[1, 2, 3] -> [[1], [2], [3]].describe:String the title of the describeprintf formatting:%p - pretty-format.%s- String.%d- Number.%i - Integer.%f - Floating point value.%j - JSON.%o - Object.%# - Index of the test case.%% - single percent sign ('%'). This does not consume an argument.$variable$variable.path.to.value$# to inject the index of the test case$variable with the printf formatting except for %%Function the suite of test/its to be ran, this is the function that will receive the parameters in each row as function arguments.test(name, fn)Alias: .it(name, fn)
js
each([
[1, 1, 2],
[1, 2, 3],
[2, 1, 3],
]).test('returns the result of adding %d to %d', (a, b, expected) => {
expect(a + b).toBe(expected);
});
js
each([
{a: 1, b: 1, expected: 2},
{a: 1, b: 2, expected: 3},
{a: 2, b: 1, expected: 3},
]).test('returns the result of adding $a to $b', ({a, b, expected}) => {
expect(a + b).toBe(expected);
});
.test.only(name, fn)Aliases: .it.only(name, fn) or .fit(name, fn)
js
each([
[1, 1, 2],
[1, 2, 3],
[2, 1, 3],
]).test.only('returns the result of adding %d to %d', (a, b, expected) => {
expect(a + b).toBe(expected);
});
.test.skip(name, fn)Aliases: .it.skip(name, fn) or .xit(name, fn) or .xtest(name, fn)
js
each([
[1, 1, 2],
[1, 2, 3],
[2, 1, 3],
]).test.skip('returns the result of adding %d to %d', (a, b, expected) => {
expect(a + b).toBe(expected);
});
.test.concurrent(name, fn)Aliases: .it.concurrent(name, fn)
js
each([
[1, 1, 2],
[1, 2, 3],
[2, 1, 3],
]).test.concurrent(
'returns the result of adding %d to %d',
(a, b, expected) => {
expect(a + b).toBe(expected);
},
);
.test.concurrent.only(name, fn)Aliases: .it.concurrent.only(name, fn)
js
each([
[1, 1, 2],
[1, 2, 3],
[2, 1, 3],
]).test.concurrent.only(
'returns the result of adding %d to %d',
(a, b, expected) => {
expect(a + b).toBe(expected);
},
);
.test.concurrent.skip(name, fn)Aliases: .it.concurrent.skip(name, fn)
js
each([
[1, 1, 2],
[1, 2, 3],
[2, 1, 3],
]).test.concurrent.skip(
'returns the result of adding %d to %d',
(a, b, expected) => {
expect(a + b).toBe(expected);
},
);
.test(name, fn(done))Alias: .it(name, fn(done))
js
each([['hello'], ['mr'], ['spy']]).test(
'gives 007 secret message: %s',
(str, done) => {
const asynchronousSpy = message => {
expect(message).toBe(str);
done();
};
callSomeAsynchronousFunction(asynchronousSpy)(str);
},
);
.describe(name, fn)``js
each([
[1, 1, 2],
[1, 2, 3],
[2, 1, 3],
]).describe('.add(%d, %d)', (a, b, expected) => {
test(returns ${expected}`, () => {
expect(a + b).toBe(expected);
});
test('does not mutate first arg', () => { a + b; expect(a).toBe(a); });
test('does not mutate second arg', () => { a + b; expect(b).toBe(b); }); }); ```
``js
each([
{a: 1, b: 1, expected: 2},
{a: 1, b: 2, expected: 3},
{a: 2, b: 1, expected: 3},
]).describe('.add($a, $b)', ({a, b, expected}) => {
test(returns ${expected}`, () => {
expect(a + b).toBe(expected);
});
test('does not mutate first arg', () => { a + b; expect(a).toBe(a); });
test('does not mutate second arg', () => { a + b; expect(b).toBe(b); }); }); ```
.describe.only(name, fn)Aliases: .fdescribe(name, fn)
js
each([
[1, 1, 2],
[1, 2, 3],
[2, 1, 3],
]).describe.only('.add(%d, %d)', (a, b, expected) => {
test(`returns ${expected}`, () => {
expect(a + b).toBe(expected);
});
});
.describe.skip(name, fn)Aliases: .xdescribe(name, fn)
js
each([
[1, 1, 2],
[1, 2, 3],
[2, 1, 3],
]).describe.skip('.add(%d, %d)', (a, b, expected) => {
test(`returns ${expected}`, () => {
expect(a + b).toBe(expected);
});
});
each[tagged template].test(name, suiteFn)js
each`
a | b | expected
${1} | ${1} | ${2}
${1} | ${2} | ${3}
${2} | ${1} | ${3}
`.test('returns $expected when adding $a to $b', ({a, b, expected}) => {
expect(a + b).toBe(expected);
});
each takes a tagged template string with:|${value} syntax..test:String the title of the test, use $variable in the name string to inject test values into the test title from the tagged template expressions$variable.path.to.value$# to inject the index of the table row.Function the test logic, this is the function that will receive the parameters of each row as function argumentseach[tagged template].describe(name, suiteFn)``js
each
a | b | expected
${1} | ${1} | ${2}
${1} | ${2} | ${3}
${2} | ${1} | ${3}
.describe('$a + $b', ({a, b, expected}) => {
test(returns ${expected}`, () => {
expect(a + b).toBe(expected);
});
test('does not mutate first arg', () => { a + b; expect(a).toBe(a); });
test('does not mutate second arg', () => { a + b; expect(b).toBe(b); }); }); ```
each takes a tagged template string with:|${value} syntax..describe:String the title of the test, use $variable in the name string to inject test values into the test title from the tagged template expressions$variable.path.to.valueFunction the suite of test/its to be ran, this is the function that will receive the parameters in each row as function arguments.test(name, fn)Alias: .it(name, fn)
js
each`
a | b | expected
${1} | ${1} | ${2}
${1} | ${2} | ${3}
${2} | ${1} | ${3}
`.test('returns $expected when adding $a to $b', ({a, b, expected}) => {
expect(a + b).toBe(expected);
});
.test.only(name, fn)Aliases: .it.only(name, fn) or .fit(name, fn)
js
each`
a | b | expected
${1} | ${1} | ${2}
${1} | ${2} | ${3}
${2} | ${1} | ${3}
`.test.only('returns $expected when adding $a to $b', ({a, b, expected}) => {
expect(a + b).toBe(expected);
});
.test.skip(name, fn)Aliases: .it.skip(name, fn) or .xit(name, fn) or .xtest(name, fn)
js
each`
a | b | expected
${1} | ${1} | ${2}
${1} | ${2} | ${3}
${2} | ${1} | ${3}
`.test.skip('returns $expected when adding $a to $b', ({a, b, expected}) => {
expect(a + b).toBe(expected);
});
.test(name, fn(done))Alias: .it(name, fn(done))
js
each`
str
${'hello'}
${'mr'}
${'spy'}
`.test('gives 007 secret message: $str', ({str}, done) => {
const asynchronousSpy = message => {
expect(message).toBe(str);
done();
};
callSomeAsynchronousFunction(asynchronousSpy)(str);
});
.describe(name, fn)``js
each
a | b | expected
${1} | ${1} | ${2}
${1} | ${2} | ${3}
${2} | ${1} | ${3}
.describe('$a + $b', ({a, b, expected}) => {
test(returns ${expected}`, () => {
expect(a + b).toBe(expected);
});
test('does not mutate first arg', () => { a + b; expect(a).toBe(a); });
test('does not mutate second arg', () => { a + b; expect(b).toBe(b); }); }); ```
.describe.only(name, fn)Aliases: .fdescribe(name, fn)
js
each`
a | b | expected
${1} | ${1} | ${2}
${1} | ${2} | ${3}
${2} | ${1} | ${3}
`.describe.only('$a + $b', ({a, b, expected}) => {
test(`returns ${expected}`, () => {
expect(a + b).toBe(expected);
});
});
.describe.skip(name, fn)Aliases: .xdescribe(name, fn)
js
each`
a | b | expected
${1} | ${1} | ${2}
${1} | ${2} | ${3}
${2} | ${1} | ${3}
`.describe.skip('$a + $b', ({a, b, expected}) => {
test(`returns ${expected}`, () => {
expect(a + b).toBe(expected);
});
});
MIT