1 files changed, 68 insertions, 0 deletions
diff --git a/spec/lib/gitlab/database/migration_spec.rb b/spec/lib/gitlab/database/migration_spec.rb
new file mode 100644
index 00000000000..287e738c24e
--- /dev/null
+++ b/spec/lib/gitlab/database/migration_spec.rb
@@ -0,0 +1,68 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Gitlab::Database::Migration do
+  describe '.[]' do
+    context 'version: 1.0' do
+      subject { described_class[1.0] }
+
+      it 'inherits from ActiveRecord::Migration[6.1]' do
+        expect(subject.superclass).to eq(ActiveRecord::Migration[6.1])
+      end
+
+      it 'includes migration helpers version 2' do
+        expect(subject.included_modules).to include(Gitlab::Database::MigrationHelpers::V2)
+      end
+
+      it 'includes LockRetriesConcern' do
+        expect(subject.included_modules).to include(Gitlab::Database::Migration::LockRetriesConcern)
+      end
+    end
+
+    context 'unknown version' do
+      it 'raises an error' do
+        expect { described_class[0] }.to raise_error(ArgumentError, /Unknown migration version/)
+      end
+    end
+  end
+
+  describe '.current_version' do
+    it 'includes current ActiveRecord migration class' do
+      # This breaks upon Rails upgrade. In that case, we'll add a new version in Gitlab::Database::Migration::MIGRATION_CLASSES,
+      # bump .current_version and leave existing migrations and already defined versions of Gitlab::Database::Migration
+      # untouched.
+      expect(described_class[described_class.current_version].superclass).to eq(ActiveRecord::Migration::Current)
+    end
+  end
+
+  describe Gitlab::Database::Migration::LockRetriesConcern do
+    subject { class_def.new }
+
+    context 'when not explicitly called' do
+      let(:class_def) do
+        Class.new do
+          include Gitlab::Database::Migration::LockRetriesConcern
+        end
+      end
+
+      it 'does not disable lock retries by default' do
+        expect(subject.enable_lock_retries?).not_to be_truthy
+      end
+    end
+
+    context 'when explicitly disabled' do
+      let(:class_def) do
+        Class.new do
+          include Gitlab::Database::Migration::LockRetriesConcern
+
+          enable_lock_retries!
+        end
+      end
+
+      it 'does not disable lock retries by default' do
+        expect(subject.enable_lock_retries?).to be_truthy
+      end
+    end
+  end
+end