fruits-repository.spec.js

import 'isomorphic-fetch';
import {expect} from 'code';
import {getFruits} from '../../src/fruits-repository';
import sinon from 'sinon';

describe('Given the fruits repository', () => {

    let fetchStub,
        sandbox;

    beforeEach(() => {

        sandbox = sinon.sandbox.create();

        fetchStub = sandbox.stub(global, 'fetch');

    });

    afterEach(() => {

        sandbox.restore();

    });

    describe('when getting a collection of fruits', () => {

        it('should call fetch', () => {

            const expectedEndPoint = '/fruits';

            fetchStub.returns(Promise.resolve());

            getFruits();

            sinon.assert.calledOnce(fetchStub);
            sinon.assert.calledWithExactly(fetchStub, expectedEndPoint);

        });

        describe('and is successful', () => {

            it('should return an array of fruits', () => {

                const expectedFruits = [
                    'apple',
                    'banana',
                    'pears'
                ];

                const json = sandbox.stub().returns(expectedFruits);

                fetchStub.returns(Promise.resolve({json}));

                return getFruits()
                    .then(data => {

                        expect(data).array().equal(expectedFruits);

                    })
                    .catch(() => {
                    
                        expect(false).true();
                    
                    });

            });

        });

        describe('and is unsuccessful', () => {

            it('should return an error object', () => {

                const expectedErrorObject = {
                    message: 'No fruits found.'
                };

                const json = sandbox.stub().returns(expectedErrorObject);

                fetchStub.returns(Promise.reject({json}));

                return getFruits()
                    .then(() => {
                    
                        expect(false).true();
                    
                    })
                    .catch(error => {

                        expect(error).object().equal(expectedErrorObject);

                    });

            });

        });

    });

});