feat: expose default_browser_type in emulated devices (#1497)

Fixes #1496.

Adds tests for documented case, too: https://playwright.dev/python/docs/emulation#devices

Author: rwoll

playwright/_impl/_playwright.py

@@ -81,4 +81,5 @@ def parse_device_descriptor(dict: Dict) -> Dict:
         "device_scale_factor": dict["deviceScaleFactor"],
         "is_mobile": dict["isMobile"],
         "has_touch": dict["hasTouch"],
+        "default_browser_type": dict["defaultBrowserType"],
     }

tests/async/test_device_descriptors.py

@@ -0,0 +1,37 @@
+import pytest
+
+
+@pytest.mark.only_browser("chromium")
+async def test_should_work(playwright) -> None:
+    device_descriptor = playwright.devices["Pixel 2"]
+    device_type = device_descriptor["default_browser_type"]
+    browser = await playwright[device_type].launch()
+    context = await browser.new_context(
+        **device_descriptor,
+    )
+    page = await context.new_page()
+    assert device_descriptor["default_browser_type"] == "chromium"
+    assert browser.browser_type.name == "chromium"
+
+    assert "Pixel 2" in device_descriptor["user_agent"]
+    assert "Pixel 2" in await page.evaluate("navigator.userAgent")
+
+    assert device_descriptor["device_scale_factor"] > 2
+    assert await page.evaluate("window.devicePixelRatio") > 2
+
+    assert device_descriptor["viewport"]["height"] > 700
+    assert device_descriptor["viewport"]["height"] < 800
+    inner_height = await page.evaluate("window.innerHeight")
+    inner_height > 700
+    inner_height < 800
+
+    assert device_descriptor["viewport"]["width"] > 400
+    assert device_descriptor["viewport"]["width"] < 500
+    inner_width = await page.evaluate("window.innerWidth")
+    inner_width > 400
+    inner_width < 500
+
+    assert device_descriptor["has_touch"]
+    assert device_descriptor["is_mobile"]
+
+    await browser.close()