1 files changed, 126 insertions, 0 deletions
diff --git a/spec/support/shared_examples/uploaders/object_storage_shared_examples.rb b/spec/support/shared_examples/uploaders/object_storage_shared_examples.rb
new file mode 100644
index 00000000000..cd9974cd6e2
--- /dev/null
+++ b/spec/support/shared_examples/uploaders/object_storage_shared_examples.rb
@@ -0,0 +1,126 @@
+shared_context 'with storage' do |store, **stub_params|
+  before do
+    subject.object_store = store
+  end
+end
+
+shared_examples "migrates" do |to_store:, from_store: nil|
+  let(:to) { to_store }
+  let(:from) { from_store || subject.object_store }
+
+  def migrate(to)
+    subject.migrate!(to)
+  end
+
+  def checksum
+    Digest::SHA256.hexdigest(subject.read)
+  end
+
+  before do
+    migrate(from)
+  end
+
+  it 'returns corresponding file type' do
+    expect(subject).to be_an(CarrierWave::Uploader::Base)
+    expect(subject).to be_a(ObjectStorage::Concern)
+
+    if from == described_class::Store::REMOTE
+      expect(subject.file).to be_a(CarrierWave::Storage::Fog::File)
+    elsif from == described_class::Store::LOCAL
+      expect(subject.file).to be_a(CarrierWave::SanitizedFile)
+    else
+      raise 'Unexpected file type'
+    end
+  end
+
+  it 'does nothing when migrating to the current store' do
+    expect { migrate(from) }.not_to change { subject.object_store }.from(from)
+  end
+
+  it 'migrate to the specified store' do
+    from_checksum = checksum
+
+    expect { migrate(to) }.to change { subject.object_store }.from(from).to(to)
+    expect(checksum).to eq(from_checksum)
+  end
+
+  it 'removes the original file after the migration' do
+    original_file = subject.file.path
+    migrate(to)
+
+    expect(File.exist?(original_file)).to be_falsey
+  end
+
+  it 'can access to the original file during migration' do
+    file = subject.file
+
+    allow(subject).to receive(:delete_migrated_file) { } # Remove as a callback of :migrate
+    allow(subject).to receive(:record_upload) { } # Remove as a callback of :store (:record_upload)
+
+    expect(file.exists?).to be_truthy
+    expect { migrate(to) }.not_to change { file.exists? }
+  end
+
+  context 'when migrate! is not oqqupied by another process' do
+    it 'executes migrate!' do
+      expect(subject).to receive(:object_store=).at_least(1)
+
+      migrate(to)
+    end
+  end
+
+  context 'when migrate! is occupied by another process' do
+    let(:exclusive_lease_key) { "object_storage_migrate:#{subject.model.class}:#{subject.model.id}" }
+
+    before do
+      @uuid = Gitlab::ExclusiveLease.new(exclusive_lease_key, timeout: 1.hour.to_i).try_obtain
+    end
+
+    it 'does not execute migrate!' do
+      expect(subject).not_to receive(:unsafe_migrate!)
+
+      expect { migrate(to) }.to raise_error('Already running')
+    end
+
+    after do
+      Gitlab::ExclusiveLease.cancel(exclusive_lease_key, @uuid)
+    end
+  end
+
+  context 'migration is unsuccessful' do
+    shared_examples "handles gracefully" do |error:|
+      it 'does not update the object_store' do
+        expect { migrate(to) }.to raise_error(error)
+        expect(subject.object_store).to eq(from)
+      end
+
+      it 'does not delete the original file' do
+        expect { migrate(to) }.to raise_error(error)
+        expect(subject.exists?).to be_truthy
+      end
+    end
+
+    context 'when the store is not supported' do
+      let(:to) { -1 } # not a valid store
+
+      include_examples "handles gracefully", error: ObjectStorage::UnknownStoreError
+    end
+
+    context 'upon a fog failure' do
+      before do
+        storage_class = subject.send(:storage_for, to).class
+        expect_any_instance_of(storage_class).to receive(:store!).and_raise("Store failure.")
+      end
+
+      include_examples "handles gracefully", error: "Store failure."
+    end
+
+    context 'upon a database failure' do
+      before do
+        expect(uploader).to receive(:persist_object_store!).and_raise("ActiveRecord failure.")
+      end
+
+      include_examples "handles gracefully", error: "ActiveRecord failure."
+    end
+  end
+end