Improve SessionActivation.activate spec (#36983)

app/models/session_activation.rb

@@ -38,9 +38,7 @@ class SessionActivation < ApplicationRecord
     end
 
     def activate(**)
-      activation = create!(**)
-      purge_old
-      activation
+      create!(**).tap { purge_old }
     end
 
     def deactivate(id)

spec/models/session_activation_spec.rb

@@ -39,20 +39,24 @@ RSpec.describe SessionActivation do
   end
 
   describe '.activate' do
-    let(:options) { { user: Fabricate(:user), session_id: '1' } }
+    let(:user) { Fabricate :user }
+    let!(:session_activation) { Fabricate :session_activation, user: }
 
-    it 'calls create! and purge_old' do
-      allow(described_class).to receive(:create!).with(**options)
-      allow(described_class).to receive(:purge_old)
-
-      described_class.activate(**options)
-
-      expect(described_class).to have_received(:create!).with(**options)
-      expect(described_class).to have_received(:purge_old)
+    around do |example|
+      original = Rails.configuration.x.max_session_activations
+      Rails.configuration.x.max_session_activations = 1
+      example.run
+      Rails.configuration.x.max_session_activations = original
     end
 
-    it 'returns an instance of SessionActivation' do
-      expect(described_class.activate(**options)).to be_a described_class
+    it 'creates a new activation and purges older ones' do
+      result = described_class.activate(user: user, session_id: '123')
+
+      expect(result)
+        .to be_a(described_class)
+        .and have_attributes(session_id: '123', user:)
+      expect { session_activation.reload }
+        .to raise_error(ActiveRecord::RecordNotFound)
     end
   end