Rely on default Mime format when MimeNegotiation#format_from_path_extension is not a valid type

Closes #22747

1 files changed, 12 insertions, 0 deletions

diff --git a/actionpack/test/dispatch/request_test.rb b/actionpack/test/dispatch/request_test.rb
index 7dd9d05e62..26386d2aa1 100644
--- a/actionpack/test/dispatch/request_test.rb
+++ b/actionpack/test/dispatch/request_test.rb
@@ -897,6 +897,18 @@ class RequestFormat < BaseRequestTest
       ActionDispatch::Request.ignore_accept_header = old_ignore_accept_header
     end
   end
+
+  test "format taken from the path extension" do
+    request = stub_request 'PATH_INFO' => '/foo.xml'
+    assert_called(request, :parameters, times: 1, returns: {}) do
+      assert_equal [Mime[:xml]], request.formats
+    end
+
+    request = stub_request 'PATH_INFO' => '/foo.123'
+    assert_called(request, :parameters, times: 1, returns: {}) do
+      assert_equal [Mime[:html]], request.formats
+    end
+  end
 end
 
 class RequestMimeType < BaseRequestTest