Add test for type ag without extension in path.

Author: Kyle McGonagle

tests/async/test_screenshot.py

@@ -71,7 +71,7 @@ async def test_should_infer_screenshot_type_from_path(
     output_png_file = tmp_path / "foo"
     await page.screenshot(path=output_png_file)
     assert_image_file_format(output_png_file, "PNG")
-    
+
 
 async def test_should_screenshot_with_type_argument(page: Page, tmp_path: Path) -> None:
     output_jpeg_with_png_extension = tmp_path / "foo_jpeg.png"
@@ -81,3 +81,7 @@ async def test_should_screenshot_with_type_argument(page: Page, tmp_path: Path)
     output_png_with_jpeg_extension = tmp_path / "bar_png.jpeg"
     await page.screenshot(path=output_png_with_jpeg_extension, type="png")
     assert_image_file_format(output_png_with_jpeg_extension, "PNG")
+
+    output_png_with_jpeg_extension = tmp_path / "bar_jpeg"
+    await page.screenshot(path=output_png_with_jpeg_extension, type="jpeg")
+    assert_image_file_format(output_png_with_jpeg_extension, "JPEG")