Remove minitest/mock

IIUC this is going away in minitest 6.0. We're only using it in a
few places, so let's try to replace those with the equivalent mocha
style stubbing.

Co-authored-by: Claude Code <noreply@anthropic.com>

Author: simonbaird

rails/test/integration/claim_sites_test.rb

@@ -1,5 +1,4 @@
 require 'test_helper'
-require 'minitest/mock'
 
 class ClaimSitesTest < CapybaraIntegrationTest
   setup do

rails/test/models/settings_test.rb

@@ -28,13 +28,10 @@ def self.quux_enabled?(_user) = false
     end
   end
 
-  def with_mocked_grant_feature_data(user_list, &)
-    stubbed = lambda do |*args|
-      assert_equal args, [:grant_feature, :foo_bar]
-      user_list
-    end
-
-    Settings.stub(:secrets, stubbed, &)
+  def with_mocked_grant_feature_data(user_list)
+    Settings.stubs(:secrets).with(:grant_feature, :foo_bar).returns(user_list)
+    yield
+    Settings.unstub(:secrets)
   end
 
   test 'manually granted feature access' do

rails/test/models/site_test.rb

@@ -296,20 +296,24 @@ def setup_some_saved_versions
     end
 
     # Main blob is missing, but no non-missing other blob was found
-    WithSavedContent.stub(:blob_exists_in_storage?, ->(_blob) { false }) do
-      assert_raises(RuntimeError, "No good blob found!") do
-        @site.reload.restore_missing_main_blob!
-      end
+    WithSavedContent.stubs(:blob_exists_in_storage?).returns(false)
+    assert_raises(RuntimeError, "No good blob found!") do
+      @site.reload.restore_missing_main_blob!
     end
+    WithSavedContent.unstub(:blob_exists_in_storage?)
 
     # Main blob missing, and there is an non-missing older blob available
-    WithSavedContent.stub(:blob_exists_in_storage?, ->(blob) { blob.id == old_blob.id }) do
-      @site.reload.restore_missing_main_blob!
+    # Set up general stub first, then specific stub for old_blob
+    WithSavedContent.stubs(:blob_exists_in_storage?).returns(false)
+    WithSavedContent.stubs(:blob_exists_in_storage?).with(old_blob).returns(true)
 
-      # Should have created a new version with the older content
-      assert_equal 3, @site.reload.saved_content_files.count
-      assert_equal 'older version', @site.file_download
-    end
+    @site.reload.restore_missing_main_blob!
+
+    # Should have created a new version with the older content
+    assert_equal 3, @site.reload.saved_content_files.count
+    assert_equal 'older version', @site.file_download
+
+    WithSavedContent.unstub(:blob_exists_in_storage?)
   end
 
   test 'tagging basic functionality' do

rails/test/test_helper.rb

@@ -9,7 +9,6 @@
 
 require 'capybara/rails'
 require 'capybara/minitest'
-require 'minitest/mock'
 require 'mocha/minitest'
 
 # Load test support modules
@@ -77,12 +76,6 @@ class ActionDispatch::IntegrationTest
   setup do
     host! Settings.url_defaults[:host]
   end
-
-  def mock_helper
-    mock = Minitest::Mock.new
-    yield mock if block_given?
-    mock
-  end
 end
 
 class CapybaraIntegrationTest < ActionDispatch::IntegrationTest