What does an E2E test look like at the code level?
An E2E test at the code level is a script that programmatically performs a sequence of actions the way a real user would in a browser, and then checks that the interface and the system as a whole produced the expected result.
The structure of such a test
It usually has three parts:
- Environment setup Launching the browser, navigating to the needed URL, preparing data or state.
- Step-by-step simulation of user actions For example: clicking a button, typing text, selecting an element, navigating the page.
- Checking the result (assertions) Checking that the needed element is displayed, the state changed, the needed text appeared, a new page opened, etc.
A mini example in Playwright
Here's what it looks like in code:
js
test('user can log in', async ({ page }) => {
await page.goto('https://site.com/login');
await page.fill('#email', 'test@mail.com');
await page.fill('#password', '123456');
await page.click('button[type=submit]');
await expect(page.getByText('Welcome')).toBeVisible();
});What the example shows
- the test opens the page
- enters data
- clicks the button
- checks the expected result
In other words, an E2E test walks through an entire business scenario in code, not a single function or component.
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