2 files changed, 12 insertions, 0 deletions
diff --git a/actionpack/test/dispatch/debug_exceptions_test.rb b/actionpack/test/dispatch/debug_exceptions_test.rb
index c85476fa38..8b1b3c0277 100644
--- a/actionpack/test/dispatch/debug_exceptions_test.rb
+++ b/actionpack/test/dispatch/debug_exceptions_test.rb
@@ -58,6 +58,8 @@ class DebugExceptionsTest < ActionDispatch::IntegrationTest
         raise ActionController::NotImplemented
       when "/unprocessable_entity"
         raise ActionController::InvalidAuthenticityToken
+      when "/invalid_mimetype"
+        raise Mime::Type::InvalidMimeType
       when "/not_found_original_exception"
         begin
           raise AbstractController::ActionNotFound.new
@@ -178,6 +180,10 @@ class DebugExceptionsTest < ActionDispatch::IntegrationTest
     get "/parameter_missing", headers: { "action_dispatch.show_exceptions" => true }
     assert_response 400
     assert_match(/ActionController::ParameterMissing/, body)
+
+    get "/invalid_mimetype", headers: { "Accept" => "text/html,*", "action_dispatch.show_exceptions" => true }
+    assert_response 406
+    assert_match(/Mime::Type::InvalidMimeType/, body)
   end
 
   test "rescue with text error for xhr request" do
diff --git a/actionpack/test/dispatch/show_exceptions_test.rb b/actionpack/test/dispatch/show_exceptions_test.rb
index f802abc653..6fafa4e426 100644
--- a/actionpack/test/dispatch/show_exceptions_test.rb
+++ b/actionpack/test/dispatch/show_exceptions_test.rb
@@ -9,6 +9,8 @@ class ShowExceptionsTest < ActionDispatch::IntegrationTest
       case req.path
       when "/not_found"
         raise AbstractController::ActionNotFound
+      when "/invalid_mimetype"
+        raise Mime::Type::InvalidMimeType
       when "/bad_params", "/bad_params.json"
         begin
           raise StandardError.new
@@ -62,6 +64,10 @@ class ShowExceptionsTest < ActionDispatch::IntegrationTest
     get "/unknown_http_method", env: { "action_dispatch.show_exceptions" => true }
     assert_response 405
     assert_equal "", body
+
+    get "/invalid_mimetype", headers: { "Accept" => "text/html,*", "action_dispatch.show_exceptions" => true }
+    assert_response 406
+    assert_equal "", body
   end
 
   test "localize rescue error page" do