Simplify the logic

scrapy/utils/request.py

@@ -143,21 +143,13 @@ class RequestFingerprinter:
         else:
             implementation = "SENTINEL"
 
-        if implementation == "SENTINEL":
-            self._fingerprint = fingerprint
-        elif implementation == "2.7":
+        if implementation != "SENTINEL":
             message = (
                 "'REQUEST_FINGERPRINTER_IMPLEMENTATION' is a deprecated setting.\n"
                 "And it will be removed in future version of Scrapy."
             )
             warnings.warn(message, category=ScrapyDeprecationWarning, stacklevel=2)
-            self._fingerprint = fingerprint
-        else:
-            raise ValueError(
-                f"Got an invalid value on setting "
-                f"'REQUEST_FINGERPRINTER_IMPLEMENTATION': "
-                f"{implementation!r}. Valid values are '2.7' and 'SENTINEL'."
-            )
+        self._fingerprint = fingerprint
 
     def fingerprint(self, request: Request) -> bytes:
         return self._fingerprint(request)

scrapy/utils/test.py

@@ -76,6 +76,7 @@ class TestSpider(Spider):
 def get_crawler(
     spidercls: Optional[Type[Spider]] = None,
     settings_dict: Optional[Dict[str, Any]] = None,
+    prevent_warnings: bool = True,
 ) -> Crawler:
     """Return an unconfigured Crawler object. If settings_dict is given, it
     will be used to populate the crawler settings with a project level
@@ -85,6 +86,8 @@ def get_crawler(
 
     # Set by default settings that prevent deprecation warnings.
     settings: Dict[str, Any] = {}
+    if prevent_warnings:
+        pass
     settings.update(settings_dict or {})
     runner = CrawlerRunner(settings)
     crawler = runner.create_crawler(spidercls or TestSpider)

tests/test_utils_request.py

@@ -277,13 +277,6 @@ class RequestFingerprinterTestCase(unittest.TestCase):
         )
         self.assertTrue(logged_warnings)
 
-    def test_unknown_implementation(self):
-        settings = {
-            "REQUEST_FINGERPRINTER_IMPLEMENTATION": "2.5",
-        }
-        with self.assertRaises(ValueError):
-            get_crawler(settings_dict=settings)
-
 
 class CustomRequestFingerprinterTestCase(unittest.TestCase):
     def test_include_headers(self):