Return suite_errors in test suite comparer

app/serializers/test_suite_comparer_entity.rb

@@ -34,4 +34,16 @@ class TestSuiteComparerEntity < Grape::Entity
   expose :resolved_errors, using: TestCaseEntity do |suite|
     suite.limited_tests.resolved_errors
   end
+
+  expose :suite_errors do |suite|
+    head_suite_error = suite.head_suite.suite_error
+    base_suite_error = suite.base_suite.suite_error
+
+    next unless head_suite_error.present? || base_suite_error.present?
+
+    {
+      head: head_suite_error,
+      base: base_suite_error
+    }
+  end
 end

spec/fixtures/api/schemas/entities/test_suite_comparer.json

@@ -26,7 +26,14 @@
     "existing_failures": { "type": "array", "items": { "$ref": "test_case.json" } },
     "new_errors": { "type": "array", "items": { "$ref": "test_case.json" } },
     "resolved_errors": { "type": "array", "items": { "$ref": "test_case.json" } },
-    "existing_errors": { "type": "array", "items": { "$ref": "test_case.json" } }
+    "existing_errors": { "type": "array", "items": { "$ref": "test_case.json" } },
+    "suite_errors": {
+      "type": ["object", "null"],
+      "properties": {
+        "head": { "type": ["string", "null"] },
+        "base": { "type": ["string", "null"] }
+      }
+    }
   },
   "additionalProperties": false
 }

spec/serializers/test_suite_comparer_entity_spec.rb

@@ -35,6 +35,7 @@ RSpec.describe TestSuiteComparerEntity do
         end
         expect(subject[:resolved_failures]).to be_empty
         expect(subject[:existing_failures]).to be_empty
+        expect(subject[:suite_errors]).to be_nil
       end
     end
 
@@ -56,6 +57,7 @@ RSpec.describe TestSuiteComparerEntity do
         end
         expect(subject[:resolved_failures]).to be_empty
         expect(subject[:existing_failures]).to be_empty
+        expect(subject[:suite_errors]).to be_nil
       end
     end
 
@@ -77,6 +79,7 @@ RSpec.describe TestSuiteComparerEntity do
           expect(existing_failure[:execution_time]).to eq(test_case_failed.execution_time)
           expect(existing_failure[:system_output]).to eq(test_case_failed.system_output)
         end
+        expect(subject[:suite_errors]).to be_nil
       end
     end
 
@@ -98,6 +101,47 @@ RSpec.describe TestSuiteComparerEntity do
           expect(resolved_failure[:system_output]).to eq(test_case_success.system_output)
         end
         expect(subject[:existing_failures]).to be_empty
+        expect(subject[:suite_errors]).to be_nil
+      end
+    end
+
+    context 'when head suite has suite error' do
+      before do
+        allow(head_suite).to receive(:suite_error).and_return('some error')
+      end
+
+      it 'contains suite error for head suite' do
+        expect(subject[:suite_errors]).to eq(
+          head: 'some error',
+          base: nil
+        )
+      end
+    end
+
+    context 'when base suite has suite error' do
+      before do
+        allow(base_suite).to receive(:suite_error).and_return('some error')
+      end
+
+      it 'contains suite error for head suite' do
+        expect(subject[:suite_errors]).to eq(
+          head: nil,
+          base: 'some error'
+        )
+      end
+    end
+
+    context 'when base and head suite both have suite errors' do
+      before do
+        allow(head_suite).to receive(:suite_error).and_return('head error')
+        allow(base_suite).to receive(:suite_error).and_return('base error')
+      end
+
+      it 'contains suite error for head suite' do
+        expect(subject[:suite_errors]).to eq(
+          head: 'head error',
+          base: 'base error'
+        )
       end
     end
   end