fix the failing spec

app/uploaders/object_storage.rb

@@ -9,6 +9,7 @@ module ObjectStorage
   RemoteStoreError = Class.new(StandardError)
   UnknownStoreError = Class.new(StandardError)
   ObjectStorageUnavailable = Class.new(StandardError)
+  ExclusiveLeaseTaken = Class.new(StandardError)
   TMP_UPLOAD_PATH = 'tmp/uploads'.freeze
@@ -378,7 +379,7 @@ module ObjectStorage
     def with_exclusive_lease
       lease_key = exclusive_lease_key
       uuid = Gitlab::ExclusiveLease.new(lease_key, timeout: 1.hour.to_i).try_obtain
-      raise "Exclusive lease #{lease_key} already taken." unless uuid
+      raise ExclusiveLeaseTaken, "Exclusive lease #{lease_key} already taken." unless uuid
       yield uuid
     ensure

spec/support/shared_examples/uploaders/object_storage_shared_examples.rb

@@ -85,13 +85,13 @@ shared_examples "migrates" do |to_store:, from_store: nil|
     it 'does not execute migrate!' do
       expect(subject).not_to receive(:unsafe_migrate!)
-      expect { migrate(to) }.to raise_error('exclusive lease already taken')
+      expect { migrate(to) }.to raise_error(ObjectStorage::ExclusiveLeaseTaken)
     end
     it 'does not execute use_file' do
       expect(subject).not_to receive(:unsafe_use_file)
-      expect { subject.use_file }.to raise_error('exclusive lease already taken')
+      expect { subject.use_file }.to raise_error(ObjectStorage::ExclusiveLeaseTaken)
     end
     after do

spec/uploaders/object_storage_spec.rb

@@ -321,7 +321,7 @@ describe ObjectStorage do
       when_file_is_in_use do
         expect(uploader).not_to receive(:unsafe_migrate!)
-        expect { uploader.migrate!(described_class::Store::REMOTE) }.to raise_error('exclusive lease already taken')
+        expect { uploader.migrate!(described_class::Store::REMOTE) }.to raise_error(ObjectStorage::ExclusiveLeaseTaken)
       end
     end
@@ -329,7 +329,7 @@ describe ObjectStorage do
       when_file_is_in_use do
         expect(uploader).not_to receive(:unsafe_use_file)
-        expect { uploader.use_file }.to raise_error('exclusive lease already taken')
+        expect { uploader.use_file }.to raise_error(ObjectStorage::ExclusiveLeaseTaken)
       end
     end
   end