Improve coverage specificity for Webhook enable/disable/secret specs (#31194)

spec/models/webhook_spec.rb

@@ -38,28 +38,28 @@ RSpec.describe Webhook do
 
   describe '#rotate_secret!' do
     it 'changes the secret' do
-      previous_value = webhook.secret
+      expect { webhook.rotate_secret! }
-      webhook.rotate_secret!
+        .to change(webhook, :secret)
-      expect(webhook.secret).to_not be_blank
+      expect(webhook.secret)
-      expect(webhook.secret).to_not eq previous_value
+        .to_not be_blank
     end
   end
 
   describe '#enable!' do
-    before do
+    let(:webhook) { Fabricate(:webhook, enabled: false) }
-      webhook.disable!
-    end
 
     it 'enables the webhook' do
-      webhook.enable!
+      expect { webhook.enable! }
-      expect(webhook.enabled?).to be true
+        .to change(webhook, :enabled?).to(true)
     end
   end
 
   describe '#disable!' do
+    let(:webhook) { Fabricate(:webhook, enabled: true) }
+
     it 'disables the webhook' do
-      webhook.disable!
+      expect { webhook.disable! }
-      expect(webhook.enabled?).to be false
+        .to change(webhook, :enabled?).to(false)
     end
   end
 end