feat(jest): mithril component testing (#3679)

* feat(jest): create jest config package for unit testing
* chore: housekeeping
* fix: now we need to explicitly allow importing without extension
* fix: recover EditorDriverInterface import
* feat(jest): mithril component testing
* fix: use separate `tsconfig.test.json`

Signed-off-by: Sami Mazouz <sychocouldy@gmail.com>

framework/core/js/tests/integration/common/components/Alert.test.ts

@@ -0,0 +1,49 @@
+import Alert from '../../../../src/common/components/Alert';
+import m from 'mithril';
+import mq from 'mithril-query';
+import { jest } from '@jest/globals';
+
+describe('Alert displays as expected', () => {
+  it('should display alert messages with an icon', () => {
+    const alert = mq(m(Alert, { type: 'error' }, 'Shoot!'));
+    expect(alert).toContainRaw('Shoot!');
+    expect(alert).toHaveElement('i.icon');
+  });
+
+  it('should display alert messages with a custom icon when using a title', () => {
+    const alert = mq(Alert, { type: 'error', icon: 'fas fa-users', title: 'Woops..' });
+    expect(alert).toContainRaw('Woops..');
+    expect(alert).toHaveElement('i.fas.fa-users');
+  });
+
+  it('should display alert messages with a title', () => {
+    const alert = mq(m(Alert, { type: 'error', title: 'Error Title' }, 'Shoot!'));
+    expect(alert).toContainRaw('Shoot!');
+    expect(alert).toContainRaw('Error Title');
+    expect(alert).toHaveElement('.Alert-title');
+  });
+
+  it('should display alert messages with custom controls', () => {
+    const alert = mq(Alert, { type: 'error', controls: [m('button', { className: 'Button--test' }, 'Click me!')] });
+    expect(alert).toHaveElement('button.Button--test');
+  });
+});
+
+describe('Alert is dismissible', () => {
+  it('should show dismiss button', function () {
+    const alert = mq(m(Alert, { dismissible: true }, 'Shoot!'));
+    expect(alert).toHaveElement('button.Alert-dismiss');
+  });
+
+  it('should call ondismiss when dismiss button is clicked', function () {
+    const ondismiss = jest.fn();
+    const alert = mq(Alert, { dismissible: true, ondismiss });
+    alert.click('.Alert-dismiss');
+    expect(ondismiss).toHaveBeenCalled();
+  });
+
+  it('should not be dismissible if not chosen', function () {
+    const alert = mq(Alert, { type: 'error', dismissible: false });
+    expect(alert).not.toHaveElement('button.Alert-dismiss');
+  });
+});

framework/core/js/tsconfig.test.json

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+{
+    "extends": "./tsconfig.json",
+    "include": ["tests/**/*"],
+    "files": ["../../../node_modules/flarum-jest-config/shims.d.ts"]
+}