Implement custom lightweight modal #230

Introduce a brand new lightweight and efficient modal component. It is
designed to be visually similar to the previous one to not introduce a
change in feel of the application in a patch release, but behind the
scenes it features:

- Enhanced application speed and reduced bundle size.
- New flexbox-driven layout, eliminating JS calculations.
- Composition API ready for Vue 3.0 #230.

Other changes:

- Adopt idiomatic Vue via `v-modal` binding.
- Add unit tests for both the modal and dialog.
- Remove `vue-js-modal` dependency in favor of the new implementation.
- Adjust modal shadow color to better match theme.
- Add `@vue/test-utils` for unit testing.

tests/unit/presentation/components/Shared/Modal/ModalDialog.spec.ts

@@ -0,0 +1,83 @@
+import 'mocha';
+import { shallowMount, mount } from '@vue/test-utils';
+import { expect } from 'chai';
+import ModalDialog from '@/presentation/components/Shared/Modal/ModalDialog.vue';
+import ModalContainer from '@/presentation/components/Shared/Modal/ModalContainer.vue';
+
+const DOM_CLOSE_BUTTON_SELECTOR = '.dialog__close-button';
+const MODAL_CONTAINER_COMPONENT_NAME = 'ModalContainer';
+
+describe('ModalDialog.vue', () => {
+  it(`renders ${MODAL_CONTAINER_COMPONENT_NAME}`, () => {
+    // arrange & act
+    const wrapper = mountComponent();
+
+    // assert
+    const modalContainerWrapper = wrapper.findComponent({ name: MODAL_CONTAINER_COMPONENT_NAME });
+    expect(modalContainerWrapper.exists()).to.equal(true);
+  });
+
+  describe(`binds the visibility flag ${MODAL_CONTAINER_COMPONENT_NAME}`, () => {
+    it('given true', () => {
+      // arrange & act
+      const wrapper = mountComponent({ modelValue: true, deepMount: true });
+
+      // assert
+      const modalContainerWrapper = wrapper.findComponent(ModalContainer);
+      expect(modalContainerWrapper.props('value')).to.equal(true);
+    });
+    it('given false', () => {
+      // arrange & act
+      const wrapper = mountComponent({ modelValue: false, deepMount: true });
+
+      // assert
+      const modalContainerWrapper = wrapper.findComponent(ModalContainer);
+      expect(modalContainerWrapper.props('value')).to.equal(false);
+    });
+  });
+
+  describe('close button', () => {
+    it('renders the close button', async () => {
+      // arrange
+      const wrapper = mountComponent({ modelValue: true });
+
+      // act
+      const closeButton = wrapper.find(DOM_CLOSE_BUTTON_SELECTOR);
+
+      // assert
+      expect(closeButton.exists()).to.equal(true);
+    });
+
+    it('closes the modal when close button is clicked', async () => {
+      // arrange
+      const wrapper = mountComponent({ modelValue: true });
+
+      // act
+      const closeButton = wrapper.find(DOM_CLOSE_BUTTON_SELECTOR);
+      await closeButton.trigger('click');
+      await wrapper.vm.$nextTick();
+
+      // assert
+      expect(wrapper.emitted().input[0]).to.deep.equal([false]);
+    });
+  });
+});
+
+function mountComponent(options?: {
+  readonly modelValue?: boolean,
+  readonly slotHtml?: string,
+  readonly deepMount?: boolean,
+}) {
+  const mountFunction = options?.deepMount === true ? mount : shallowMount;
+  const wrapper = mountFunction(ModalDialog as unknown, {
+    propsData: options?.modelValue !== undefined ? { value: options?.modelValue } : undefined,
+    slots: options?.slotHtml !== undefined ? { default: options?.slotHtml } : undefined,
+    stubs: options?.deepMount === true ? undefined : {
+      [MODAL_CONTAINER_COMPONENT_NAME]: {
+        name: MODAL_CONTAINER_COMPONENT_NAME,
+        template: '<slot />',
+      },
+    },
+  });
+  return wrapper;
+}