Fixes simplecov-ruby#624 Only write last run result on successes

features/maximum_coverage_drop.feature

@@ -85,5 +85,55 @@ Feature:
         }
       }
       """
+  Scenario: test failures do not update the resultset
+    Given SimpleCov for RSpec is configured with:
+      """
+      require 'simplecov'
+      SimpleCov.start do
+        add_group 'Libs', 'lib/faked_project/'
+        add_filter '/spec/'
+        maximum_coverage_drop 0
+      end
+      """
+
+    And a file named "lib/faked_project/missed.rb" with:
+      """
+      class UncoveredSourceCode
+        def foo
+          never_reached
+        rescue => err
+          but no one cares about invalid ruby here
+        end
+      end
+      """
+
+    And a file named "spec/failing_spec.rb" with:
+      """
+      require "spec_helper"
+      describe FakedProject do
+        it "fails" do
+          expect(false).to eq(true)
+        end
+      end
+      """
+    And the file named "coverage/.last_run.json" with:
+      """
+      {
+        "result": {
+          "covered_percent": 100.0
+        }
+      }
+      """
 
+    When I run `bundle exec rspec spec`
+    Then the exit status should be 1
+    And a file named "coverage/.last_run.json" should exist
+    And the file "coverage/.last_run.json" should contain:
+      """
+      {
+        "result": {
+          "covered_percent": 100.0
+        }
+      }
+      """
 

lib/simplecov/defaults.rb

@@ -78,7 +78,9 @@
       elsif covered_percentages.any? { |p| p < SimpleCov.minimum_coverage_by_file } # rubocop:disable Metrics/BlockNesting
         $stderr.printf("File (%s) is only (%.2f%%) covered. This is below the expected minimum coverage per file of (%.2f%%).\n", SimpleCov.result.least_covered_file, covered_percentages.min, SimpleCov.minimum_coverage_by_file)
         @exit_status = SimpleCov::ExitCodes::MINIMUM_COVERAGE
-      elsif (last_run = SimpleCov::LastRun.read) # rubocop:disable Metrics/BlockNesting
+      end
+
+      if (last_run = SimpleCov::LastRun.read) # rubocop:disable Metrics/BlockNesting
         coverage_diff = last_run["result"]["covered_percent"] - covered_percent
         if coverage_diff > SimpleCov.maximum_coverage_drop # rubocop:disable Metrics/BlockNesting
           $stderr.printf("Coverage has dropped by %.2f%% since the last time (maximum allowed: %.2f%%).\n", coverage_diff, SimpleCov.maximum_coverage_drop)
@@ -87,8 +89,7 @@
       end
     end
 
-    # Don't overwrite last_run file if refuse_coverage_drop option is enabled and the coverage has dropped
-    unless @exit_status == SimpleCov::ExitCodes::MAXIMUM_COVERAGE_DROP
+    if @exit_status == SimpleCov::ExitCodes::SUCCESS
       SimpleCov::LastRun.write(:result => {:covered_percent => covered_percent})
     end
   end