test-scenarios

Easily run the same unit test with different test data.

Not tied to a specific library, it can be used with

• mocha
• jasmine
• jest
• any library where tests are defined within a function.

Example

// sum.js
export const sum = (a, b) => a + b;

// sum.test.js
import scenarios from "test-scenarios";

describe("sum", () => {
  scenarios([
    { a: 1, b: 2, result: 3 },
    { a: -1, b: 1, result: 0 }
  ], ({ a, b, result }, scenarioIndex) => {
    describe(`Case ${scenarioIndex}: when ${a} and ${b} are passed`, () => {
      it(`should return ${result}`, () => {
        expect(sum(a, b)).toEqual(result);
      });
    });
  });
});

Example output

 PASS  ./sum.test.js
  sum
    Case 0: when 1 and 2 are passed
      ✓ should return 3 (4ms)
    Case 1: when -1 and 1 are passed
      ✓ should return 0

API

scenarios(testScenarios, testsFn)

• testScenarios: any contains the test data for every scenario.
• testsFn: Function the test function to run each time with different data, it can be a whole describe block or multiple it/test wrapped into a function. It will be invoked with:
  • parameters: any the data for the scenario
  • index: number the scenario index

Note for Jest users

You can achieve the same result as the above by using the following syntax:

describe.each([
  { a: 1, b: 2, result: 3 },
  { a: -1, b: 1, result: 0 }
])('sum', ({ a, b, result }) => {
  describe(`When ${a} and ${b} are passed`, () => {
    it(`should return ${result}`, () => {
      expect(sum(a, b)).toEqual(result);
    });
  });
});

More info on describe.each and test.each.