[TASK-1046] Introduce unit tests for UI components

.eslintrc.js

@@ -43,7 +43,7 @@ const jsRules = {
   'react/no-multi-comp': 0,
   'react/no-unknown-property': 0,
   'react/prop-types': 0,
-  'react/react-in-jsx-scope': 2,
+  // 'react/react-in-jsx-scope': 2,
   'react/self-closing-comp': 2,
   'react/wrap-multilines': 0,
   strict: 1,

.github/workflows/npm-test.yml

@@ -78,3 +78,6 @@ jobs:
         # Timeout early to make it easier to manually re-run jobs.
         # Tracking issue: https://github.com/kobotoolbox/kpi/issues/4337
         timeout-minutes: 1
+
+      - name: Run components tests with Jest
+        run: npm run jest

jsapp/jest/jest.config.ts

@@ -0,0 +1,15 @@
+import type {Config} from 'jest';
+
+const config: Config = {
+  verbose: true,
+  testEnvironment: 'jsdom',
+  roots: ['<rootDir>/../js', '<rootDir>'],
+  moduleNameMapper: {
+    '^js/(.*)$': '<rootDir>/../js/$1',
+    '\\.(css|scss)$': 'identity-obj-proxy',
+  },
+  setupFilesAfterEnv: ['<rootDir>/setupJestTest.ts'],
+  transform: {'^.+\\.(t|j)sx?$': '@swc/jest'},
+};
+
+export default config;

jsapp/jest/setupJestTest.ts

@@ -0,0 +1,4 @@
+import '@testing-library/jest-dom/jest-globals';
+import '@testing-library/jest-dom';
+
+global.t = (str: string) => str;

jsapp/js/components/common/button.spec.tsx

@@ -0,0 +1,66 @@
+import Button from './button';
+
+import {render, screen} from '@testing-library/react';
+import {describe, it, expect, jest} from '@jest/globals';
+import userEvent from '@testing-library/user-event';
+
+const user = userEvent.setup();
+
+describe('Enabled button', () => {
+  // Mock
+  const handleClickFunction = jest.fn();
+
+  beforeEach(() => {
+    render(
+      <Button
+        type='primary'
+        size='l'
+        label='Button Label'
+        onClick={handleClickFunction}
+      />
+    );
+  });
+
+  it('should render', async () => {
+    // Assert
+    expect(screen.getByLabelText('Button Label')).toBeInTheDocument();
+  });
+
+  it('should be clickable', async () => {
+    // Act
+    const button = screen.getByLabelText('Button Label');
+    await user.click(button);
+
+    expect(handleClickFunction).toHaveBeenCalledTimes(1);
+  });
+});
+
+describe('Disabled button', () => {
+  // Mock
+  const handleClickFunction = jest.fn();
+
+  beforeEach(() => {
+    render(
+      <Button
+        type='primary'
+        size='l'
+        label='Button Label'
+        onClick={handleClickFunction}
+        isDisabled
+      />
+    );
+  });
+
+  it('should render', async () => {
+    // Assert
+    expect(screen.getByLabelText('Button Label')).toBeInTheDocument();
+  });
+
+  it('should not be clickable', async () => {
+    // Act
+    const button = screen.getByLabelText('Button Label');
+    await user.click(button);
+
+    expect(handleClickFunction).not.toHaveBeenCalled();
+  });
+});

jsapp/js/components/special/koboAccessibleSelect.spec.tsx

@@ -0,0 +1,136 @@
+import {fireEvent, render, screen} from '@testing-library/react';
+import {describe, it, expect, jest} from '@jest/globals';
+import userEvent from '@testing-library/user-event';
+import type {KoboSelectOption} from './koboAccessibleSelect';
+import KoboSelect3 from './koboAccessibleSelect';
+import {useState} from 'react';
+
+const options: KoboSelectOption[] = [
+  {value: '1', label: 'Apple'},
+  {value: '2', label: 'Banana'},
+  {value: '3', label: 'Avocado'},
+];
+
+// A wrapper is needed for the component to retain value changes
+const Wrapper = ({onChange}: {onChange: (newValue: string) => void}) => {
+  const [value, setValue] = useState<string>('');
+
+  const handleChange = (newValue: string | null = '') => {
+    setValue(newValue || '');
+    onChange(newValue || '');
+  };
+
+  return (
+    <KoboSelect3
+      name='testSelect'
+      options={options}
+      value={value}
+      onChange={handleChange}
+    />
+  );
+};
+
+
+describe('KoboSelect3', () => {
+  const user = userEvent.setup();
+
+  // Mock
+  const scrollIntoViewMock = jest.fn();
+  window.HTMLElement.prototype.scrollIntoView = scrollIntoViewMock;
+  const onChangeMock = jest.fn();
+
+  beforeEach(() => {
+    render(<Wrapper onChange={onChangeMock} />);
+  });
+
+  it('should render with proper placeholder', async () => {
+    const trigger = screen.getByRole('combobox');
+    const triggerLabel = trigger.querySelector('label');
+    expect(trigger).toBeInTheDocument();
+    expect(triggerLabel).toHaveTextContent('Select…');
+  });
+
+  it('should have the list closed on start', async () => {
+    const list = screen.getByRole('listbox');
+    expect(list.dataset.expanded).toBe('false');
+  });
+
+  it('should have a list with the correct items count', async () => {
+    const listOptions = screen.getAllByRole('option');
+    expect(listOptions).toHaveLength(3);
+  });
+
+  it('should be selectable by mouse click', async () => {
+      const trigger = screen.getByRole('combobox');
+      const list = screen.getByRole('listbox');
+      const listOptions = screen.getAllByRole('option');
+
+      // Clicks the trigger
+      await user.click(trigger);
+      expect(list.dataset.expanded).toBe('true');
+
+      // Select first option
+      await user.click(listOptions[0]);
+
+      // Onchange should be called with the correct value
+      expect(onChangeMock).lastCalledWith(options[0].value);
+
+      expect(list.dataset.expanded).toBe('false');
+  });
+
+  it('should be selectable by keyboard arrows', async () => {
+      const trigger = screen.getByRole('combobox');
+      const triggerLabel = trigger.querySelector('label');
+
+      // No item selected
+      expect(triggerLabel).toHaveTextContent('Select…');
+
+      // Increase option on arrow down
+      fireEvent.keyDown(trigger, {key: 'ArrowDown'});
+      expect(onChangeMock).lastCalledWith(options[0].value);
+      expect(triggerLabel).toHaveTextContent(options[0].label);
+
+      // Increase option on arrow right
+      fireEvent.keyDown(trigger, {key: 'ArrowRight'});
+      expect(onChangeMock).lastCalledWith(options[1].value);
+      expect(triggerLabel).toHaveTextContent(options[1].label);
+      fireEvent.keyDown(trigger, {key: 'ArrowRight'});
+      expect(onChangeMock).lastCalledWith(options[2].value);
+      expect(triggerLabel).toHaveTextContent(options[2].label);
+
+      // Don't go past the last one
+      onChangeMock.mockReset();
+      fireEvent.keyDown(trigger, {key: 'ArrowDown'});
+      expect(onChangeMock).not.toHaveBeenCalled();
+      expect(triggerLabel).toHaveTextContent(options[2].label);
+
+      // Decrease option on arrow up
+      fireEvent.keyDown(trigger, {key: 'ArrowUp'});
+      expect(onChangeMock).lastCalledWith(options[1].value);
+      expect(triggerLabel).toHaveTextContent(options[1].label);
+
+      // Decrease option on arrow left
+      fireEvent.keyDown(trigger, {key: 'ArrowLeft'});
+      expect(onChangeMock).lastCalledWith(options[0].value);
+      expect(triggerLabel).toHaveTextContent(options[0].label);
+
+      // Don't go past the first one
+      onChangeMock.mockReset();
+      fireEvent.keyDown(trigger, {key: 'ArrowUp'});
+      expect(onChangeMock).not.toHaveBeenCalled();
+      expect(triggerLabel).toHaveTextContent(options[0].label);
+  });
+
+  it('should be selectable by typing', async () => {
+      const trigger = screen.getByRole('combobox');
+      const triggerLabel = trigger.querySelector('label');
+
+      // No item selected
+      expect(triggerLabel).toHaveTextContent('Select…');
+
+      // Type 'b' to select Banana
+      fireEvent.keyDown(trigger, {key: 'b'});
+      expect(onChangeMock).lastCalledWith(options[1].value);
+      expect(triggerLabel).toHaveTextContent(options[1].label);
+  });
+});

jsapp/js/components/special/koboAccessibleSelect.tsx

@@ -381,7 +381,8 @@ interface KoboSelect3Props {
   // 'data-cy'?: string;  // not yet needed
 }
 
-interface KoboSelectOption {
+/** Needs to be exported to be referenced in the test file. */
+export interface KoboSelectOption {
   /** Must be unique! */
   value: string;
   /** Should be unique, too! */