old_contents: import { mount } from '@vue/test-utils';
  import SignInPage from '../../src/views/SignInPage';
  import makeStore from '../makeStore';
  
  jest.mock('kolibri.urls');
  
  function makeWrapper() {
    return mount(SignInPage, {
      store: makeStore(),
    });
  }
  
  describe('signInPage component', () => {
    it('smoke test', () => {
      const wrapper = makeWrapper();
      expect(wrapper.isVueInstance()).toEqual(true);
    });
  });
  
new_contents: import { mount } from '@vue/test-utils';
  import SignInPage from '../../src/views/SignInPage';
  import makeStore from '../makeStore';
  
  jest.mock('kolibri.urls');
  
  function makeWrapper() {
    return mount(SignInPage, {
      store: makeStore(),
    });
  }
  
  describe('signInPage component', () => {
    it('smoke test', () => {
      const wrapper = makeWrapper();
      expect(wrapper.isVueInstance()).toEqual(true);
    });
    it('will set the username as invalid if it contains punctuation and is blurred', () => {
      const wrapper = makeWrapper();
      wrapper.setData({ username: '?', usernameBlurred: true });
      expect(wrapper.vm.usernameIsInvalid).toEqual(true);
    });
    it('will set the form as not valid if the username is invalid and is blurred', () => {
      const wrapper = makeWrapper();
      wrapper.setData({ username: '?', usernameBlurred: true });
      expect(wrapper.vm.formIsValid).toEqual(false);
    });
    it('will set the validation text to required if the username is empty and blurred', () => {
      const wrapper = makeWrapper();
      wrapper.setData({ username: '', usernameBlurred: true });
      expect(wrapper.vm.usernameIsInvalidText).toEqual(wrapper.vm.$options.$trs.required);
    });
    it('will set the validation text to empty if the username is empty and not blurred', () => {
      const wrapper = makeWrapper();
      wrapper.setData({ username: '', usernameBlurred: false });
      expect(wrapper.vm.usernameIsInvalidText).toEqual('');
    });
  });
  
subject: Add tests of username validation on sign in page.