1 files changed, 102 insertions, 0 deletions
diff --git a/spec/graphql/resolvers/paginated_tree_resolver_spec.rb b/spec/graphql/resolvers/paginated_tree_resolver_spec.rb
new file mode 100644
index 00000000000..82b05937aa3
--- /dev/null
+++ b/spec/graphql/resolvers/paginated_tree_resolver_spec.rb
@@ -0,0 +1,102 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Resolvers::PaginatedTreeResolver do
+  include GraphqlHelpers
+
+  let_it_be(:project) { create(:project, :repository) }
+  let_it_be(:repository) { project.repository }
+
+  specify do
+    expect(described_class).to have_nullable_graphql_type(Types::Tree::TreeType.connection_type)
+  end
+
+  describe '#resolve', :aggregate_failures do
+    subject { resolve_repository(args, opts) }
+
+    let(:args) { { ref: 'master' } }
+    let(:opts) { {} }
+
+    let(:start_cursor) { subject.start_cursor }
+    let(:end_cursor) { subject.end_cursor }
+    let(:items) { subject.items }
+    let(:entries) { items.first.entries }
+
+    it 'resolves to a collection with a tree object' do
+      expect(items.first).to be_an_instance_of(Tree)
+
+      expect(start_cursor).to be_nil
+      expect(end_cursor).to be_blank
+      expect(entries.count).to eq(repository.tree.entries.count)
+    end
+
+    context 'with recursive option' do
+      let(:args) { super().merge(recursive: true) }
+
+      it 'resolve to a recursive tree' do
+        expect(entries[4].path).to eq('files/html')
+      end
+    end
+
+    context 'with limited max_page_size' do
+      let(:opts) { { max_page_size: 5 } }
+
+      it 'resolves to a pagination collection with a tree object' do
+        expect(items.first).to be_an_instance_of(Tree)
+
+        expect(start_cursor).to be_nil
+        expect(end_cursor).to be_present
+        expect(entries.count).to eq(5)
+      end
+    end
+
+    context 'when repository does not exist' do
+      before do
+        allow(repository).to receive(:exists?).and_return(false)
+      end
+
+      it 'returns nil' do
+        is_expected.to be(nil)
+      end
+    end
+
+    describe 'Cursor pagination' do
+      context 'when cursor is invalid' do
+        let(:args) { super().merge(after: 'invalid') }
+
+        it { expect { subject }.to raise_error(Gitlab::Graphql::Errors::ArgumentError) }
+      end
+
+      it 'returns all tree entries during cursor pagination' do
+        cursor = nil
+
+        expected_entries = repository.tree.entries.map(&:path)
+        collected_entries = []
+
+        loop do
+          result = resolve_repository(args.merge(after: cursor), max_page_size: 10)
+
+          collected_entries += result.items.first.entries.map(&:path)
+
+          expect(result.start_cursor).to eq(cursor)
+          cursor = result.end_cursor
+
+          break if cursor.blank?
+        end
+
+        expect(collected_entries).to match_array(expected_entries)
+      end
+    end
+  end
+
+  def resolve_repository(args, opts = {})
+    field_options = described_class.field_options.merge(
+      owner: resolver_parent,
+      name: 'field_value'
+    ).merge(opts)
+
+    field = ::Types::BaseField.new(**field_options)
+    resolve_field(field, repository, args: args, object_type: resolver_parent)
+  end
+end