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Unit tests for forms pages

Last updated: November 26, 2024

Use the following guidelines when writing a unit test for forms pages.

import { expect } from 'chai';
import { render, screen } from '@testing-library/react';
import { DefinitionTester } from 'platform/testing/unit/schemaform-utils';

describe('MyForm FormID', () => {
  const {
    schema,
    uiSchema,
    arrayPath,
  } = formConfig.chapters.myFormChapter.pages.myFormPage;

  it('renders the form with the correct number of inputs', () => {
    render(
      <DefinitionTester
        arrayPath={arrayPath}
        pagePerItemIndex={0}
        definitions={formConfig.defaultDefinitions}
        schema={schema}
        data={initialData}
        formData={initialData}
        uiSchema={uiSchema}
      />,
    );

    expect(screen.getAllByRole('combobox')).to.have.lengthOf(6);
    expect(screen.getAllByRole('textbox')).to.have.lengthOf(4);
  });
});

  • Organize forms config tests by page.

  • Use <DefinitionTester /> to render form configs for testing.

  • Test at least the following:

    • Number of each type of input is rendered (example above)

    • Any conditional display logic on the page

    • All field level validation errors

When working with RTL, you can use its native functions for filling out form data:

  • fireEvent.change() - simulates user interaction with an input field, but trades the realism of a user input for faster test resolution

test('fills data in a field', () => {
  render(<DefinitionTester />);
  
  const selectElement = screen.getByLabelText(/blah/i);
  fireEvent.change(selectElement, { target: { value: 'USA' } });
  
  expect(selectElement.value).toBe('USA');
});

  • userEvent.type() - works largely the same as fireEvent.change(), but more accurately approximates real user behavior with a component

test('fills data in a field', async () => {
  render(<DefinitionTester />);
  
  const selectElement = screen.getByLabelText(/blah/i);
  await userEvent.type(selectElement, 'USA');
  
  expect(selectElement.value).toBe('USA');
});

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