Fix code quality comparer

This commit refactors our codequalitycomparer class and returns a
status not found if a base report or head report is missing.

lib/gitlab/ci/reports/codequality_reports_comparer.rb

@@ -5,7 +5,7 @@ module Gitlab
     module Reports
       class CodequalityReportsComparer < ReportsComparer
         def initialize(base_report, head_report)
-          @base_report = base_report || CodequalityReports.new
+          @base_report = base_report
           @head_report = head_report
         end
 
@@ -15,12 +15,16 @@ module Gitlab
 
         def existing_errors
           strong_memoize(:existing_errors) do
+            next [] if not_found?
+
             base_report.all_degradations & head_report.all_degradations
           end
         end
 
         def new_errors
           strong_memoize(:new_errors) do
+            next [] if not_found?
+
             fingerprints = head_report.degradations.keys - base_report.degradations.keys
             head_report.degradations.fetch_values(*fingerprints)
           end
@@ -28,6 +32,8 @@ module Gitlab
 
         def resolved_errors
           strong_memoize(:resolved_errors) do
+            next [] if not_found?
+
             fingerprints = base_report.degradations.keys - head_report.degradations.keys
             base_report.degradations.fetch_values(*fingerprints)
           end

lib/gitlab/ci/reports/reports_comparer.rb

@@ -18,10 +18,10 @@ module Gitlab
         end
 
         def status
-          if success?
-            STATUS_SUCCESS
-          elsif base_report.nil? || head_report.nil?
+          if base_report.nil? || head_report.nil?
             STATUS_NOT_FOUND
+          elsif success?
+            STATUS_SUCCESS
           else
             STATUS_FAILED
           end
@@ -54,6 +54,10 @@ module Gitlab
         def total_count
           existing_errors.size + new_errors.size
         end
+
+        def not_found?
+          status == STATUS_NOT_FOUND
+        end
       end
     end
   end

spec/lib/gitlab/ci/reports/codequality_reports_comparer_spec.rb

@@ -27,6 +27,22 @@ RSpec.describe Gitlab::Ci::Reports::CodequalityReportsComparer do
         expect(report_status).to eq(described_class::STATUS_SUCCESS)
       end
     end
+
+    context 'when head report does not exist' do
+      let(:head_report) { nil }
+
+      it 'returns status not found' do
+        expect(report_status).to eq(described_class::STATUS_NOT_FOUND)
+      end
+    end
+
+    context 'when base report does not exist' do
+      let(:base_report) { nil }
+
+      it 'returns status success' do
+        expect(report_status).to eq(described_class::STATUS_NOT_FOUND)
+      end
+    end
   end
 
   describe '#errors_count' do
@@ -93,6 +109,14 @@ RSpec.describe Gitlab::Ci::Reports::CodequalityReportsComparer do
         expect(resolved_count).to be_zero
       end
     end
+
+    context 'when base report is nil' do
+      let(:base_report) { nil }
+
+      it 'returns zero' do
+        expect(resolved_count).to be_zero
+      end
+    end
   end
 
   describe '#total_count' do
@@ -140,6 +164,14 @@ RSpec.describe Gitlab::Ci::Reports::CodequalityReportsComparer do
         expect(total_count).to eq(2)
       end
     end
+
+    context 'when base report is nil' do
+      let(:base_report) { nil }
+
+      it 'returns zero' do
+        expect(total_count).to be_zero
+      end
+    end
   end
 
   describe '#existing_errors' do
@@ -177,6 +209,14 @@ RSpec.describe Gitlab::Ci::Reports::CodequalityReportsComparer do
         expect(existing_errors).to be_empty
       end
     end
+
+    context 'when base report is nil' do
+      let(:base_report) { nil }
+
+      it 'returns an empty array' do
+        expect(existing_errors).to be_empty
+      end
+    end
   end
 
   describe '#new_errors' do
@@ -213,6 +253,14 @@ RSpec.describe Gitlab::Ci::Reports::CodequalityReportsComparer do
         expect(new_errors).to eq([degradation_1])
       end
     end
+
+    context 'when base report is nil' do
+      let(:base_report) { nil }
+
+      it 'returns an empty array' do
+        expect(new_errors).to be_empty
+      end
+    end
   end
 
   describe '#resolved_errors' do
@@ -250,5 +298,13 @@ RSpec.describe Gitlab::Ci::Reports::CodequalityReportsComparer do
         expect(resolved_errors).to be_empty
       end
     end
+
+    context 'when base report is nil' do
+      let(:base_report) { nil }
+
+      it 'returns an empty array' do
+        expect(resolved_errors).to be_empty
+      end
+    end
   end
 end

spec/lib/gitlab/ci/reports/reports_comparer_spec.rb

@@ -49,10 +49,6 @@ RSpec.describe Gitlab::Ci::Reports::ReportsComparer do
     context 'when base_report is nil' do
       let(:base_report) { nil }
 
-      before do
-        allow(comparer).to receive(:success?).and_return(false)
-      end
-
       it 'returns status not_found' do
         expect(status).to eq('not_found')
       end
@@ -61,10 +57,6 @@ RSpec.describe Gitlab::Ci::Reports::ReportsComparer do
     context 'when head_report is nil' do
       let(:head_report) { nil }
 
-      before do
-        allow(comparer).to receive(:success?).and_return(false)
-      end
-
       it 'returns status not_found' do
         expect(status).to eq('not_found')
       end
@@ -118,4 +110,22 @@ RSpec.describe Gitlab::Ci::Reports::ReportsComparer do
       expect { total_count }.to raise_error(NotImplementedError)
     end
   end
+
+  describe '#not_found?' do
+    subject(:not_found) { comparer.not_found? }
+
+    context 'when base report is nil' do
+      let(:base_report) { nil }
+
+      it { is_expected.to be_truthy }
+    end
+
+    context 'when base report exists' do
+      before do
+        allow(comparer).to receive(:success?).and_return(true)
+      end
+
+      it { is_expected.to be_falsey }
+    end
+  end
 end