1 files changed, 88 insertions, 0 deletions
diff --git a/spec/graphql/resolvers/design_management/design_resolver_spec.rb b/spec/graphql/resolvers/design_management/design_resolver_spec.rb
new file mode 100644
index 00000000000..857acc3d371
--- /dev/null
+++ b/spec/graphql/resolvers/design_management/design_resolver_spec.rb
@@ -0,0 +1,88 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe Resolvers::DesignManagement::DesignResolver do
+  include GraphqlHelpers
+  include DesignManagementTestHelpers
+
+  before do
+    enable_design_management
+  end
+
+  describe '#resolve' do
+    let_it_be(:issue) { create(:issue) }
+    let_it_be(:project) { issue.project }
+    let_it_be(:first_version) { create(:design_version) }
+    let_it_be(:first_design) { create(:design, issue: issue, versions: [first_version]) }
+    let_it_be(:current_user) { create(:user) }
+    let_it_be(:design_on_other_issue) do
+      create(:design, issue: create(:issue, project: project), versions: [create(:design_version)])
+    end
+
+    let(:args) { { id: GitlabSchema.id_from_object(first_design).to_s } }
+    let(:gql_context) { { current_user: current_user } }
+
+    before do
+      project.add_developer(current_user)
+    end
+
+    context 'when the user cannot see designs' do
+      let(:gql_context) { { current_user: create(:user) } }
+
+      it 'returns nothing' do
+        expect(resolve_design).to be_nil
+      end
+    end
+
+    context 'when no argument has been passed' do
+      let(:args) { {} }
+
+      it 'raises an error' do
+        expect { resolve_design }.to raise_error(::Gitlab::Graphql::Errors::ArgumentError, /must/)
+      end
+    end
+
+    context 'when both arguments have been passed' do
+      let(:args) { { filename: first_design.filename, id: GitlabSchema.id_from_object(first_design).to_s } }
+
+      it 'raises an error' do
+        expect { resolve_design }.to raise_error(::Gitlab::Graphql::Errors::ArgumentError, /may/)
+      end
+    end
+
+    context 'by ID' do
+      it 'returns the specified design' do
+        expect(resolve_design).to eq(first_design)
+      end
+
+      context 'the ID belongs to a design on another issue' do
+        let(:args) { { id: GitlabSchema.id_from_object(design_on_other_issue).to_s } }
+
+        it 'returns nothing' do
+          expect(resolve_design).to be_nil
+        end
+      end
+    end
+
+    context 'by filename' do
+      let(:args) { { filename: first_design.filename } }
+
+      it 'returns the specified design' do
+        expect(resolve_design).to eq(first_design)
+      end
+
+      context 'the filename belongs to a design on another issue' do
+        let(:args) { { filename: design_on_other_issue.filename } }
+
+        it 'returns nothing' do
+          expect(resolve_design).to be_nil
+        end
+      end
+    end
+  end
+
+  def resolve_design
+    resolve(described_class, obj: issue.design_collection, args: args, ctx: gql_context)
+  end
+end