Financial-Times / n-error

describe('nError', () => {

	describe('is a constructor function creates nError instance', () => {

		it('with .stack to trace the callStack', () => {

			const e = nError({

				message: 'some message',

				type: 'SOME_TYPE',

			});

			expect(e instanceof nError).toBe(true);

			expect(e.stack.length).toBeGreaterThan(0);

			expect(e).toMatchSnapshot();

		});

		it('exposes all fileds including .stack in Object.assign', () => {

			const e = nError({ message: 'test', a: 'a', b: 'b' });

			const ee = Object.assign(e, { c: 'c' });

			expect(ee.stack.length).toBeGreaterThan(0);

			expect(ee.stack).toBe(e.stack);

			expect(ee instanceof nError).toBe(true);

			expect(ee).toMatchSnapshot();

		});

		it('with .extend() prototype method that creates new instance and maintains the stack', () => {

			const e = nError({ message: 'some message' });

			const ee = e.extend({ next: 'TEST' });

			expect(ee).not.toBe(e);

			expect(ee.stack.toString()).toContain('__tests__/creator.js:37');

			expect(ee.stack.length).toBeGreaterThan(0);

			expect(ee).toMatchSnapshot();

		});

		it('with .remove() prototype method that creates new instance and maintains the stack', () => {

			const e = nError({

				message: 'some message',

				type: 'SOME_TYPE',

			});

			const ee = e.remove('type');

			expect(ee).not.toBe(e);

			expect(ee.stack.toString()).toContain('__tests__/creator.js:46');

			expect(ee).toMatchSnapshot();

		});

	});

	describe('function has methods as nError creator', () => {

		it('of status named after error type in camelCase', () => {

			const e = nError.notFound({ message: 'some error message' });

			expect(e.status).toBe(404);

			expect(e).toMatchSnapshot();

		});

		it('for all status defined in ERROR_STATUS_TEXT_MAP', () => {

			const methods = Object.keys(nError);

			expect(methods).toHaveLength(Object.keys(ERROR_STATUS_TEXT_MAP).length);

		});

	});

});