playwright/docs/src/debug.md

---
id: debug
title: "Debugging Tests"
---

The Playwright inspector is a great tool to help with debugging. It opens up a browser window highlighting the selectors as you step through each line of the test. You can also use the explore button to find other available [selectors](./selectors.md) which you can then copy into your test file and rerun your tests to see if it passes.


## Playwright Inspector

Playwright Inspector is a GUI tool that helps authoring and debugging Playwright scripts. That's our default recommended tool for scripts troubleshooting.

<img width="712" alt="Playwright Inspector" src="https://user-images.githubusercontent.com/883973/108614092-8c478a80-73ac-11eb-9597-67dfce110e00.png"></img>

There are several ways of opening Playwright Inspector:

### Using --debug
* langs: js

- Debugging all Tests

  ```bash
  npx playwright test --debug
  ```
- Debugging one test

  ```bash
  npx playwright test example --debug
  ```

### Using PWDEBUG

Set the `PWDEBUG` environment variable to run your scripts in debug mode. This
configures Playwright for debugging and opens the inspector.

  ```bash tab=bash-bash lang=js
  PWDEBUG=1 npm run test
  ```

  ```batch tab=bash-batch lang=js
  set PWDEBUG=1
  npm run test
  ```

  ```powershell tab=bash-powershell lang=js
  $env:PWDEBUG=1
  npm run test
  ```

  ```bash tab=bash-bash lang=java
  # Source directories in the list are separated by : on macos and linux and by ; on win.
  PWDEBUG=1 PLAYWRIGHT_JAVA_SRC=<java source dirs> mvn test
  ```

  ```batch tab=bash-batch lang=java
  # Source directories in the list are separated by : on macos and linux and by ; on win.
  set PLAYWRIGHT_JAVA_SRC=<java source dirs>
  set PWDEBUG=1
  mvn test
  ```

  ```powershell tab=bash-powershell lang=java
  # Source directories in the list are separated by : on macos and linux and by ; on win.
  $env:PLAYWRIGHT_JAVA_SRC="<java source dirs>"
  $env:PWDEBUG=1
  mvn test
  ```

  ```bash tab=bash-bash lang=python
  PWDEBUG=1 pytest -s
  ```

  ```batch tab=bash-batch lang=python
  set PWDEBUG=1
  pytest -s
  ```

  ```powershell tab=bash-powershell lang=python
  $env:PWDEBUG=1
  pytest -s
  ```

  ```bash tab=bash-bash lang=csharp
  PWDEBUG=1 dotnet test
  ```

  ```batch tab=bash-batch lang=csharp
  set PWDEBUG=1
  dotnet test
  ```

  ```powershell tab=bash-powershell lang=csharp
  $env:PWDEBUG=1
  dotnet test
  ```

  Additional useful defaults are configured when `PWDEBUG=1` is set:
  - Browsers launch in the headed mode
  - Default timeout is set to 0 (= no timeout)

Using `PWDEBUG=console` will configure the browser for debugging in Developer tools console:
* **Runs headed**: Browsers always launch in headed mode
* **Disables timeout**: Sets default timeout to 0 (= no timeout)
* **Console helper**: Configures a `playwright` object in the browser to generate and highlight
[Playwright selectors](./selectors.md). This can be used to verify text or
composite selectors.

```bash tab=bash-bash lang=js
PWDEBUG=console npm run test
```

```batch tab=bash-batch lang=js
set PWDEBUG=console
npm run test
```

```powershell tab=bash-powershell lang=js
$env:PWDEBUG="console"
npm run test
```

```bash tab=bash-bash lang=java
PWDEBUG=console mvn test
```

```batch tab=bash-batch lang=java
set PWDEBUG=console
mvn test
```

```powershell tab=bash-powershell lang=java
$env:PWDEBUG="console"
mvn test
```

```bash tab=bash-bash lang=python
PWDEBUG=console pytest -s
```

```batch tab=bash-batch lang=python
set PWDEBUG=console
pytest -s
```

```powershell tab=bash-powershell lang=python
$env:PWDEBUG="console"
pytest -s
```

#### Selectors in Developer Tools Console

When running in Debug Mode with `PWDEBUG=console`, a `playwright` object is available in Developer tools console.

1. Run with `PWDEBUG=console`
1. Setup a breakpoint to pause the execution
1. Open the console panel in browser developer tools
1. Use the `playwright` API
    * `playwright.$(selector)`: Highlight the first occurrence of the selector. This reflects
      how `page.$` would see the page.
    * `playwright.$$(selector)`: Highlight all occurrences of the selector. This reflects
      how `page.$$` would see the page.
    * `playwright.inspect(selector)`: Inspect the selector in the Elements panel.
    * `playwright.locator(selector)`: Highlight the first occurrence of the locator.
    * `playwright.clear()`: Clear existing highlights.
    * `playwright.selector(element)`: Generate a selector that points to the element.

<a href="https://user-images.githubusercontent.com/284612/86857345-299abc00-c073-11ea-9e31-02923a9f0d4b.png"><img src="https://user-images.githubusercontent.com/284612/86857345-299abc00-c073-11ea-9e31-02923a9f0d4b.png" width="500" alt="Highlight selectors"></img></a>


### Using page.pause

Call [`method: Page.pause`] method from your script when running in headed browser.

  ```js
  // Pause on the following line.
  await page.pause();
  ```

  ```java
  // Pause on the following line.
  page.pause();
  ```

  ```python async
  # Pause on the following line.
  await page.pause()
  ```

  ```python sync
  # Pause on the following line.
  page.pause()
  ```

  ```csharp
  // Pause on the following line.
  await page.PauseAsync();
  ```


- Use `open` or `codegen` commands in the Playwright [CLI](./cli.md):
  ```bash js
  npx playwright codegen wikipedia.org
  ```

  ```bash java
  mvn exec:java -e -Dexec.mainClass=com.microsoft.playwright.CLI -Dexec.args="codegen wikipedia.org"
  ```

  ```bash python
  playwright codegen wikipedia.org
  ```

  ```bash csharp
  pwsh bin\Debug\netX\playwright.ps1 codegen wikipedia.org
  ```

## Stepping through the Playwright script

When `PWDEBUG=1` is set, Playwright Inspector window will be opened and the script will be
paused on the first Playwright statement:

<img width="557" alt="Paused on line" src="https://user-images.githubusercontent.com/883973/108614337-71761580-73ae-11eb-9f61-3d29c52c9520.png"></img>

Now we know what action is about to be performed and we can look into the details on that
action. For example, when stopped on an input action such as `click`, the exact point Playwright is about to click is highlighted with the large red dot on the inspected page:

<img width="344" alt="Red dot on inspected page" src="https://user-images.githubusercontent.com/883973/108614363-b69a4780-73ae-11eb-8f5e-51f9c91ec9b4.png"></img>

By the time Playwright has paused on that click action, it has already performed actionability checks that can be found in the log:

<img width="712" alt="Action log" src="https://user-images.githubusercontent.com/883973/108614564-72a84200-73b0-11eb-9de2-828b28d78b36.png"></img>

If actionability can't be reached, it'll show action as pending:

<img width="712" alt="Pending action" src="https://user-images.githubusercontent.com/883973/108614840-e6e3e500-73b2-11eb-998f-0cf31b2aa9a2.png"></img>

You can step over each action using the "Step over" action (keyboard shortcut: `F10`) or resume script without further pauses (`F8`):

<center><img width="98" alt="Stepping toolbar" src="https://user-images.githubusercontent.com/883973/108614389-f9f4b600-73ae-11eb-8df2-8d9ce9da5d5c.png"></img></center>


## Browser Developer Tools

You can use browser developer tools in Chromium, Firefox and WebKit while running
a Playwright script in headed mode. Developer tools help to:

* Inspect the DOM tree and **find element selectors**
* **See console logs** during execution (or learn how to [read logs via API](./api/class-page.md#page-event-console))
* Check **network activity** and other developer tools features

<a href="https://user-images.githubusercontent.com/284612/77234134-5f21a500-6b69-11ea-92ec-1c146e1333ec.png"><img src="https://user-images.githubusercontent.com/284612/77234134-5f21a500-6b69-11ea-92ec-1c146e1333ec.png" width="500" alt="Chromium Developer Tools"></img></a>

Using a [`method: Page.pause`] method is an easy way to pause the Playwright script execution
and inspect the page in Developer tools. It will also open [Playwright Inspector](./inspector.md) to help with debugging.

**For Chromium**: you can also open developer tools through a launch option.
```js
await chromium.launch({ devtools: true });
```

```java
chromium.launch(new BrowserType.LaunchOptions().setDevtools(true));
```

```python async
await chromium.launch(devtools=True)
```

```python sync
chromium.launch(devtools=True)
```

```csharp
await using var browser = await playwright.Chromium.LaunchAsync(new()
{
  Devtools: true
});
```

:::note
**For WebKit**: launching WebKit Inspector during the execution will
  prevent the Playwright script from executing any further.
:::

## Debugging Selectors

- Click the Explore button to hover over elements in the screen and click them to
automatically generate selectors for those elements.
- To verify where selector points, paste it into the inspector input field:

<img width="602" alt="Selectors toolbar" src="https://user-images.githubusercontent.com/883973/108614696-ad5eaa00-73b1-11eb-81f5-9eebe62543a2.png"></img>

You can also use the following API inside the Developer Tools Console of any browser.

<img src="https://user-images.githubusercontent.com/284612/92536317-37dd9380-f1ee-11ea-875d-daf1b206dd56.png"></img>

#### playwright.$(selector)

Query Playwright selector, using the actual Playwright query engine, for example:

```js
> playwright.$('.auth-form >> text=Log in');

<button>Log in</button>
```

#### playwright.$$(selector)

Same as `playwright.$`, but returns all matching elements.

```js
> playwright.$$('li >> text=John')

> [<li>, <li>, <li>, <li>]
```

#### playwright.inspect(selector)

Reveal element in the Elements panel (if DevTools of the respective browser supports it).

```js
> playwright.inspect('text=Log in')
```

#### playwright.locator(selector)

Query Playwright element using the actual Playwright query engine, for example:

```js
> playwright.locator('.auth-form', { hasText: 'Log in' });

> Locator ()
>   - element: button
>   - elements: [button]
```

#### playwright.selector(element)

Generates selector for the given element.

```js
> playwright.selector($0)

"div[id="glow-ingress-block"] >> text=/.*Hello.*/"
```

<!-- ## Recording scripts

At any moment, clicking Record action enables [codegen mode](./codegen.md).
Every action on the target page is turned into the generated script:

<img width="712" alt="Recorded script" src="https://user-images.githubusercontent.com/883973/108614897-85704600-73b3-11eb-8bcd-f2e129786c49.png"></img>

You can copy entire generated script or clear it using toolbar actions. -->


## Run Tests in headed mode

Playwright runs browsers in headless mode by default. To change this behavior,
use `headless: false` as a launch option. You can also use the [`option: slowMo`] option
to slow down execution and follow along while debugging.

```js
await chromium.launch({ headless: false, slowMo: 100 }); // or firefox, webkit
```

```java
chromium.launch(new BrowserType.LaunchOptions() // or firefox, webkit
  .setHeadless(false)
  .setSlowMo(100));
```

```python async
await chromium.launch(headless=False, slow_mo=100) # or firefox, webkit

```

```python sync
chromium.launch(headless=False, slow_mo=100) # or firefox, webkit

```

```csharp
// Chromium, Firefox, or Webkit
await using var browser = await playwright.Chromium.LaunchAsync(new()
{
    Headless = false,
    SlowMo = 100
});
```

## Verbose API logs

Playwright supports verbose logging with the `DEBUG` environment variable.

```bash tab=bash-bash lang=js
DEBUG=pw:api npm run test
```

```batch tab=bash-batch lang=js
set DEBUG=pw:api
npm run test
```

```powershell tab=bash-powershell lang=js
$env:DEBUG="pw:api"
npm run test
```

```bash tab=bash-bash lang=java
DEBUG=pw:api mvn test
```

```batch tab=bash-batch lang=java
set DEBUG=pw:api
mvn test
```

```powershell tab=bash-powershell lang=java
$env:DEBUG="pw:api"
mvn test
```

```bash tab=bash-bash lang=python
DEBUG=pw:api pytest -s
```

```batch tab=bash-batch lang=python
set DEBUG=pw:api
pytest -s
```

```powershell tab=bash-powershell lang=python
$env:DEBUG="pw:api"
pytest -s
```

```bash tab=bash-bash lang=csharp
DEBUG=pw:api dotnet run
```

```batch tab=bash-batch lang=csharp
set DEBUG=pw:api
dotnet run
```

```powershell tab=bash-powershell lang=csharp
$env:DEBUG="pw:api"
dotnet run
```

## What's Next

- [Generate tests with Codegen](./codegen.md)
- [See a trace of your tests](./trace-viewer.md)