1 files changed, 175 insertions, 0 deletions
diff --git a/spec/lib/gitlab/git/blame_pagination_spec.rb b/spec/lib/gitlab/git/blame_pagination_spec.rb
new file mode 100644
index 00000000000..1f3c0c0342e
--- /dev/null
+++ b/spec/lib/gitlab/git/blame_pagination_spec.rb
@@ -0,0 +1,175 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Gitlab::Git::BlamePagination, feature_category: :source_code_management do
+  subject(:blame_pagination) { described_class.new(blob, blame_mode, 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(:blame_mode) do
+    instance_double(
+      'Gitlab::Git::BlameMode',
+      'streaming?' => streaming_mode,
+      'full?' => full_mode
+    )
+  end
+
+  let(:params) { { page: page } }
+  let(:page) { 1 }
+  let(:streaming_mode) { false }
+  let(:full_mode) { false }
+
+  using RSpec::Parameterized::TableSyntax
+
+  describe '#page' do
+    subject { blame_pagination.page }
+
+    where(:page, :expected_page) do
+      nil | 1
+      1   | 1
+      5   | 5
+      -1  | 1
+      'a' | 1
+    end
+
+    with_them do
+      it { is_expected.to eq(expected_page) }
+    end
+  end
+
+  describe '#per_page' do
+    subject { blame_pagination.per_page }
+
+    it { is_expected.to eq(described_class::PAGINATION_PER_PAGE) }
+
+    context 'when blame mode is streaming' do
+      let(:streaming_mode) { true }
+
+      it { is_expected.to eq(described_class::STREAMING_PER_PAGE) }
+    end
+  end
+
+  describe '#total_pages' do
+    subject { blame_pagination.total_pages }
+
+    before do
+      stub_const("#{described_class.name}::PAGINATION_PER_PAGE", 2)
+    end
+
+    it { is_expected.to eq(2) }
+  end
+
+  describe '#total_extra_pages' do
+    subject { blame_pagination.total_extra_pages }
+
+    before do
+      stub_const("#{described_class.name}::PAGINATION_PER_PAGE", 2)
+    end
+
+    it { is_expected.to eq(1) }
+  end
+
+  describe '#pagination' do
+    subject { blame_pagination.paginator }
+
+    before do
+      stub_const("#{described_class.name}::PAGINATION_PER_PAGE", 2)
+    end
+
+    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 user disabled the pagination' do
+      let(:full_mode) { true }
+
+      it { is_expected.to be_nil }
+    end
+
+    context 'when user chose streaming' do
+      let(:streaming_mode) { true }
+
+      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}::PAGINATION_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 'Pagination attributes' do
+      where(:page, :current_page, :total_pages) do
+        1 | 1 | 2
+        2 | 2 | 2
+        0 | 1 | 2 # Incorrect
+      end
+
+      with_them do
+        it 'returns the correct pagination attributes' do
+          expect(subject.current_page).to eq(current_page)
+          expect(subject.total_pages).to eq(total_pages)
+        end
+      end
+    end
+  end
+
+  describe '#blame_range' do
+    subject { blame_pagination.blame_range }
+
+    before do
+      stub_const("#{described_class.name}::PAGINATION_PER_PAGE", 2)
+    end
+
+    where(:page, :expected_range) do
+      1 | (1..2)
+      2 | (3..4)
+      0 | (1..2)
+    end
+
+    with_them do
+      it { is_expected.to eq(expected_range) }
+    end
+
+    context 'when user disabled the pagination' do
+      let(:full_mode) { true }
+
+      it { is_expected.to be_nil }
+    end
+
+    context 'when streaming is enabled' do
+      let(:streaming_mode) { true }
+
+      before do
+        stub_const("#{described_class.name}::STREAMING_FIRST_PAGE_SIZE", 1)
+        stub_const("#{described_class.name}::STREAMING_PER_PAGE", 1)
+      end
+
+      where(:page, :expected_range) do
+        1 | (1..1)
+        2 | (2..2)
+        0 | (1..1)
+      end
+
+      with_them do
+        it { is_expected.to eq(expected_range) }
+      end
+    end
+  end
+end