1 files changed, 129 insertions, 0 deletions
diff --git a/spec/services/projects/blame_service_spec.rb b/spec/services/projects/blame_service_spec.rb
new file mode 100644
index 00000000000..40b2bc869dc
--- /dev/null
+++ b/spec/services/projects/blame_service_spec.rb
@@ -0,0 +1,129 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Projects::BlameService, :aggregate_failures do
+  subject(:service) { described_class.new(blob, commit, params) }
+
+  let_it_be(:project) { create(:project, :repository) }
+  let_it_be(:commit) { project.repository.commit }
+  let_it_be(:blob) { project.repository.blob_at('HEAD', 'README.md') }
+
+  let(:params) { { page: page } }
+  let(:page) { nil }
+
+  before do
+    stub_const("#{described_class.name}::PER_PAGE", 2)
+  end
+
+  describe '#blame' do
+    subject { service.blame }
+
+    it 'returns a correct Gitlab::Blame object' do
+      is_expected.to be_kind_of(Gitlab::Blame)
+
+      expect(subject.blob).to eq(blob)
+      expect(subject.commit).to eq(commit)
+      expect(subject.range).to eq(1..2)
+    end
+
+    describe 'Pagination range calculation' do
+      subject { service.blame.range }
+
+      context 'with page = 1' do
+        let(:page) { 1 }
+
+        it { is_expected.to eq(1..2) }
+      end
+
+      context 'with page = 2' do
+        let(:page) { 2 }
+
+        it { is_expected.to eq(3..4) }
+      end
+
+      context 'with page = 3 (overlimit)' do
+        let(:page) { 3 }
+
+        it { is_expected.to eq(1..2) }
+      end
+
+      context 'with page = 0 (incorrect)' do
+        let(:page) { 0 }
+
+        it { is_expected.to eq(1..2) }
+      end
+
+      context 'when feature flag disabled' do
+        before do
+          stub_feature_flags(blame_page_pagination: false)
+        end
+
+        it { is_expected.to be_nil }
+      end
+    end
+  end
+
+  describe '#pagination' do
+    subject { service.pagination }
+
+    it 'returns a pagination object' do
+      is_expected.to be_kind_of(Kaminari::PaginatableArray)
+
+      expect(subject.current_page).to eq(1)
+      expect(subject.total_pages).to eq(2)
+      expect(subject.total_count).to eq(4)
+    end
+
+    context 'when feature flag disabled' do
+      before do
+        stub_feature_flags(blame_page_pagination: false)
+      end
+
+      it { is_expected.to be_nil }
+    end
+
+    context 'when per_page is above the global max per page limit' do
+      before do
+        stub_const("#{described_class.name}::PER_PAGE", 1000)
+        allow(blob).to receive_message_chain(:data, :lines, :count) { 500 }
+      end
+
+      it 'returns a correct pagination object' do
+        is_expected.to be_kind_of(Kaminari::PaginatableArray)
+
+        expect(subject.current_page).to eq(1)
+        expect(subject.total_pages).to eq(1)
+        expect(subject.total_count).to eq(500)
+      end
+    end
+
+    describe 'Current page' do
+      subject { service.pagination.current_page }
+
+      context 'with page = 1' do
+        let(:page) { 1 }
+
+        it { is_expected.to eq(1) }
+      end
+
+      context 'with page = 2' do
+        let(:page) { 2 }
+
+        it { is_expected.to eq(2) }
+      end
+
+      context 'with page = 3 (overlimit)' do
+        let(:page) { 3 }
+
+        it { is_expected.to eq(1) }
+      end
+
+      context 'with page = 0 (incorrect)' do
+        let(:page) { 0 }
+
+        it { is_expected.to eq(1) }
+      end
+    end
+  end
+end