Change artifacts and cache fields to arrays

app/models/ci/build.rb

@@ -524,11 +524,11 @@ module Ci
     end
 
     def artifacts
-      options[:artifacts]
+      [options[:artifacts]]
     end
 
     def cache
-      options[:cache]
+      [options[:cache]]
     end
 
     def credentials

spec/requests/api/runner_spec.rb

@@ -308,11 +308,16 @@ describe API::Runner do
              { 'key' => 'DB_NAME', 'value' => 'postgres', 'public' => true }]
           end
           let(:expected_artifacts) do
-            { 'name' => 'artifacts_file',
+            [{ 'name' => 'artifacts_file',
                'untracked' => false,
                'paths' => %w(out/),
                'when' => 'always',
-              'expire_in' => '7d' }
+               'expire_in' => '7d' }]
+          end
+          let(:expected_cache) do
+            [{ 'key' => 'cache_key',
+               'untracked' => false,
+               'paths' => ['vendor/*'] }]
           end
 
           it 'starts a job' do
@@ -329,6 +334,7 @@ describe API::Runner do
             expect(json_response['services']).to eq([{ 'name' => 'postgres' }])
             expect(json_response['steps']).to eq(expected_steps)
             expect(json_response['artifacts']).to eq(expected_artifacts)
+            expect(json_response['cache']).to eq(expected_cache)
             expect(json_response['variables']).to include(*expected_variables)
           end