1 files changed, 112 insertions, 0 deletions
diff --git a/spec/lib/gitlab/graphql/connections/keyset_connection_spec.rb b/spec/lib/gitlab/graphql/connections/keyset_connection_spec.rb
new file mode 100644
index 00000000000..96615ae80de
--- /dev/null
+++ b/spec/lib/gitlab/graphql/connections/keyset_connection_spec.rb
@@ -0,0 +1,112 @@
+require 'spec_helper'
+
+describe Gitlab::Graphql::Connections::KeysetConnection do
+  let(:nodes) { Project.all.order(id: :asc) }
+  let(:arguments) {  {} }
+  subject(:connection) do
+    described_class.new(nodes, arguments, max_page_size: 3)
+  end
+
+  def encoded_property(value)
+    Base64.strict_encode64(value.to_s)
+  end
+
+  describe '#cursor_from_nodes' do
+    let(:project) { create(:project) }
+
+    it 'returns an encoded ID' do
+      expect(connection.cursor_from_node(project))
+        .to eq(encoded_property(project.id))
+    end
+
+    context 'when an order was specified' do
+      let(:nodes) { Project.order(:updated_at) }
+
+      it 'returns the encoded value of the order' do
+        expect(connection.cursor_from_node(project))
+          .to eq(encoded_property(project.updated_at))
+      end
+    end
+  end
+
+  describe '#sliced_nodes' do
+    let(:projects) { create_list(:project, 4) }
+
+    context 'when before is passed' do
+      let(:arguments) { { before: encoded_property(projects[1].id) } }
+
+      it 'only returns the project before the selected one' do
+        expect(subject.sliced_nodes).to contain_exactly(projects.first)
+      end
+
+      context 'when the sort order is descending' do
+        let(:nodes) { Project.all.order(id: :desc) }
+
+        it 'returns the correct nodes' do
+          expect(subject.sliced_nodes).to contain_exactly(*projects[2..-1])
+        end
+      end
+    end
+
+    context 'when after is passed' do
+      let(:arguments) { { after: encoded_property(projects[1].id) } }
+
+      it 'only returns the project before the selected one' do
+        expect(subject.sliced_nodes).to contain_exactly(*projects[2..-1])
+      end
+
+      context 'when the sort order is descending' do
+        let(:nodes) { Project.all.order(id: :desc) }
+
+        it 'returns the correct nodes' do
+          expect(subject.sliced_nodes).to contain_exactly(projects.first)
+        end
+      end
+    end
+
+    context 'when both before and after are passed' do
+      let(:arguments) do
+        {
+          after: encoded_property(projects[1].id),
+          before: encoded_property(projects[3].id)
+        }
+      end
+
+      it 'returns the expected set' do
+        expect(subject.sliced_nodes).to contain_exactly(projects[2])
+      end
+    end
+  end
+
+  describe '#paged_nodes' do
+    let!(:projects) { create_list(:project, 5) }
+
+    it 'returns the collection limited to max page size' do
+      expect(subject.paged_nodes.size).to eq(3)
+    end
+
+    context 'when `first` is passed' do
+      let(:arguments) { { first: 2 } }
+
+      it 'returns only the first elements' do
+        expect(subject.paged_nodes).to contain_exactly(projects.first, projects.second)
+      end
+    end
+
+    context 'when `last` is passed' do
+      let(:arguments) { { last: 2 } }
+
+      it 'returns only the last elements' do
+        expect(subject.paged_nodes).to contain_exactly(projects[3], projects[4])
+      end
+    end
+
+    context 'when both are passed' do
+      let(:arguments) { { first: 2, last: 2 } }
+
+      it 'raises an error' do
+        expect { subject.paged_nodes }.to raise_error(Gitlab::Graphql::Errors::ArgumentError)
+      end
+    end
+  end
+end