Fix RSpec/VerifiedDoubles cop (#25469)

spec/lib/activitypub/activity/add_spec.rb

@@ -26,7 +26,7 @@ RSpec.describe ActivityPub::Activity::Add do
     end
 
     context 'when status was not known before' do
-      let(:service_stub) { double }
+      let(:service_stub) { instance_double(ActivityPub::FetchRemoteStatusService) }
 
       let(:json) do
         {

spec/lib/activitypub/activity/move_spec.rb

@@ -26,7 +26,7 @@ RSpec.describe ActivityPub::Activity::Move do
     stub_request(:post, old_account.inbox_url).to_return(status: 200)
     stub_request(:post, new_account.inbox_url).to_return(status: 200)
 
-    service_stub = double
+    service_stub = instance_double(ActivityPub::FetchRemoteAccountService)
     allow(ActivityPub::FetchRemoteAccountService).to receive(:new).and_return(service_stub)
     allow(service_stub).to receive(:call).and_return(returned_account)
   end

spec/lib/request_spec.rb

@@ -48,7 +48,7 @@ describe Request do
       end
 
       it 'executes a HTTP request when the first address is private' do
-        resolver = double
+        resolver = instance_double(Resolv::DNS)
 
         allow(resolver).to receive(:getaddresses).with('example.com').and_return(%w(0.0.0.0 2001:4860:4860::8844))
         allow(resolver).to receive(:timeouts=).and_return(nil)
@@ -83,7 +83,7 @@ describe Request do
       end
 
       it 'raises Mastodon::ValidationError' do
-        resolver = double
+        resolver = instance_double(Resolv::DNS)
 
         allow(resolver).to receive(:getaddresses).with('example.com').and_return(%w(0.0.0.0 2001:db8::face))
         allow(resolver).to receive(:timeouts=).and_return(nil)

spec/lib/suspicious_sign_in_detector_spec.rb

@@ -7,7 +7,7 @@ RSpec.describe SuspiciousSignInDetector do
     subject { described_class.new(user).suspicious?(request) }
 
     let(:user) { Fabricate(:user, current_sign_in_at: 1.day.ago) }
-    let(:request) { double(remote_ip: remote_ip) }
+    let(:request) { instance_double(ActionDispatch::Request, remote_ip: remote_ip) }
     let(:remote_ip) { nil }
 
     context 'when user has 2FA enabled' do