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unit

Helpers library for writing tramvai specific unit-tests

It might be even more useful when used with @tramvai/test-mocks

Installation

npm i --save-dev @tramvai/test-unit

How to

Testing reducers

import { testReducer } from '@tramvai/test-unit';

it('test', async () => {
const { dispatch, getState } = testReducer(reducer);

expect(getState()).toEqual([]);

dispatch(event(1));

expect(getState()).toEqual([1]);
});

More examples

import { createEvent, createReducer } from '@tramvai/state';
import { testReducer } from './testReducer';

describe('test/unit/testReducer', () => {
it('should handle state change', () => {
const handle = jest.fn((state: number[], payload: number) => {
return [...state, payload];
});
const event = createEvent<number>('push');
const reducer = createReducer('test', [] as number[]).on(event, handle);

const { dispatch, getState } = testReducer(reducer);

expect(getState()).toEqual([]);
expect(handle).not.toHaveBeenCalled();

dispatch(event(1));

expect(getState()).toEqual([1]);
expect(handle).toHaveBeenCalledWith([], 1);

dispatch(event(3));

expect(getState()).toEqual([1, 3]);
expect(handle).toHaveBeenCalledWith([1], 3);
});

it('should handle several tests reducers at separate', () => {
const event = createEvent<number>('push');
const reducer = createReducer('test', [] as number[]).on(event, (state, payload) => {
return [...state, payload];
});

const test1 = testReducer(reducer);
const test2 = testReducer(reducer);

expect(test1.getState()).toEqual([]);
expect(test2.getState()).toEqual([]);

test1.dispatch(event(1));

expect(test1.getState()).toEqual([1]);
expect(test2.getState()).toEqual([]);

test2.dispatch(event(2));

expect(test1.getState()).toEqual([1]);
expect(test2.getState()).toEqual([2]);
});
});

Testing actions

Tramvai context and DI will be created automatically, otherwise you can directly pass it as an argument.

import { testAction } from '@tramvai/test-unit';

it('test', async () => {
const { run, context } = testAction(action, { initialState: { a: 1 } });

expect(await run(true)).toBe('hello');
expect(await run(false)).toBe('world');

context.getState(); // { a: 1 }
});

More examples

import { createAction, declareAction } from '@tramvai/core';
import { createEvent } from '@tramvai/state';
import { createMockStore } from '@tramvai/test-mocks';
import { testAction } from './testAction';

describe('test/unit/state/testAction', () => {
it('should call action', async () => {
const action = createAction({
name: 'test',
fn: (context, payload: boolean) => {
if (payload) {
return 'hello';
}

return 'world';
},
});

const { run } = testAction(action);

expect(await run(true)).toBe('hello');
expect(await run(false)).toBe('world');
});

it('should call action with custom context', async () => {
const store = createMockStore();
const event = createEvent<string>('test');

const action = declareAction({
name: 'dispatch',
fn(payload: string) {
return this.dispatch(event(`action${payload}`));
},
});

const spyDispatch = jest.spyOn(store, 'dispatch');

const { run } = testAction(action, { store });

await run('ping');

expect(spyDispatch).toHaveBeenCalledWith({ payload: 'actionping', type: 'test' });

await run('pong');

expect(spyDispatch).toHaveBeenCalledWith({ payload: 'actionpong', type: 'test' });
});

it('should not require payload', async () => {
const action = declareAction({
name: 'no-payload',
fn() {
return 'empty';
},
});

const { run } = testAction(action);

await expect(run()).resolves.toBe('empty');
});
});

Testing tramvai module

Testing module in isolation

import { testModule } from '@tramvai/test-unit';

it('test', async () => {
const { di, module, runLine } = testModule(TestModule);

expect(module).toBeInstanceOf(TestModule);
expect(di.get('testToken')).toEqual({ a: 1 });

// Run only specific command line in order to execute handlers for this line inside module
await runLine(commandLineListTokens.generatePage);
});

Testing module in conjunction with other modules

import { createTestApp } from '@tramvai/test-unit';

it('test', async () => {
const { app } = await createTestApp({ modules: [TestModule, DependentModule] });

// get tokens from di implemented by module
expect(app.di.get('testToken')).toEqual({ a: 1 });
});

More examples

import { commandLineListTokens, DI_TOKEN, Module } from '@tramvai/core';
import { Container } from '@tinkoff/dippy';
import { testModule } from './testModule';

describe('test/unit/module/testModule`', () => {
it('should test module', () => {
const mockConstructor = jest.fn();

@Module({
providers: [
{
provide: 'testToken',
useFactory: () => {
return { a: 1 };
},
},
],
deps: {
di: DI_TOKEN,
optToken: { token: 'optional_token', optional: true },
},
})
class TestModule {
constructor(deps: any) {
mockConstructor(deps);
}
}

const { di, module } = testModule(TestModule);

expect(module).toBeInstanceOf(TestModule);
expect(mockConstructor).toHaveBeenCalledWith({ di: expect.any(Container), optToken: null });
expect(di.get('testToken')).toEqual({ a: 1 });
});

it('should test command line', async () => {
const mock = jest.fn();

@Module({
providers: [
{
provide: commandLineListTokens.generatePage,
multi: true,
useFactory: () => {
return mock;
},
},
],
})
class TestModule {}

const { runLine } = testModule(TestModule);

expect(() => runLine(commandLineListTokens.customerStart)).toThrow();
expect(mock).not.toHaveBeenCalled();

await runLine(commandLineListTokens.generatePage);

expect(mock).toHaveBeenCalledWith();
});
});

Adding providers to DI

Most of the helpers accepts option providers which allows to redefine already existing providers or add new.

For example, passing providers to helper testAction allows to access this provider inside action itself:

import { declareAction } from '@tramvai/core';
import { testAction } from '@tramvai/test-unit';

const action = declareAction({
name: 'action',
fn() {
console.log(this.deps.test); // token value
},
deps: {
test: 'token name',
},
});

it('test', async () => {
const { run } = testAction(action, {
providers: [
{
provide: 'token name',
useValue: 'token value',
},
],
});
});

Create app only for testing

import { createTestApp } from '@tramvai/test-unit';

it('test', async () => {
const { app } = await createTestApp({ modules: [TestModule, DependentModule] });

// get tokens from di implemented by module
expect(app.di.get('testToken')).toEqual({ a: 1 });
});

More examples

import http from 'http';
import { ENV_MANAGER_TOKEN } from '@tramvai/tokens-common';
import { SERVER_TOKEN } from '@tramvai/tokens-server';
import { CommonModule } from '@tramvai/module-common';
import { createTestApp } from './createTestApp';

describe('test/unit/app/createTestApp', () => {
it('should return app', async () => {
const { app, close } = await createTestApp();
const envManager = app.di.get(ENV_MANAGER_TOKEN);

expect(envManager.get('FRONT_LOG_API')).toBe('test');
expect(envManager.get('TEST_ENV')).toBeUndefined();
expect(app.di.get(SERVER_TOKEN)).toBeInstanceOf(http.Server);

return close();
});

it('should specify env', async () => {
const { app, close } = await createTestApp({
env: {
TEST_ENV: '1234',
},
});

const envManager = app.di.get(ENV_MANAGER_TOKEN);

expect(envManager.get('FRONT_LOG_API')).toBe('test');
expect(envManager.get('TEST_ENV')).toBe('1234');

return close();
});

it('should ignore default modules', async () => {
const { app } = await createTestApp({
excludeDefaultModules: true,
modules: [CommonModule],
});

expect(() => app.di.get(SERVER_TOKEN)).toThrow('Token not found');
});

it('should return mocker instance', async () => {
const { mocker, close } = await createTestApp();

expect(mocker).toBeDefined();

return close();
});
});