Resultset is updated when coverage drops if no drop rule specified

* Create Features that check the resultset.json is updated when
  no maximum_coverage_drop is configured
* Fix the implementation to not accidentally enable to coverage
  drop feature and then override the resultset.json

features/maximum_coverage_drop.feature

@@ -4,7 +4,7 @@ Feature:
   Exit code should be non-zero if the overall coverage decreases by more than
   the maximum_coverage_drop threshold.
 
-  Scenario:
+  Scenario: maximum_coverage_drop configured cam cause spec failure
     Given SimpleCov for Test/Unit is configured with:
       """
       require 'simplecov'
@@ -33,4 +33,57 @@ Feature:
     Then the exit status should not be 0
     And the output should contain "Coverage has dropped by 3.32% since the last time (maximum allowed: 3.14%)."
     And a file named "coverage/.last_run.json" should exist
+    And the file "coverage/.last_run.json" should contain:
+      """
+      {
+        "result": {
+          "covered_percent": 88.1
+        }
+      }
+      """
+
+  Scenario: maximum_coverage_drop not configured updates resultset
+    Given SimpleCov for Test/Unit is configured with:
+      """
+      require 'simplecov'
+      SimpleCov.start do
+        add_filter 'test.rb'
+      end
+      """
+
+    When I run `bundle exec rake test`
+    Then the exit status should be 0
+    And a file named "coverage/.last_run.json" should exist
+    And the file "coverage/.last_run.json" should contain:
+      """
+      {
+        "result": {
+          "covered_percent": 88.1
+        }
+      }
+      """
+
+    Given 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
+      """
+
+    When I run `bundle exec rake test`
+    Then the exit status should be 0
+    And a file named "coverage/.last_run.json" should exist
+    And the file "coverage/.last_run.json" should contain:
+      """
+      {
+        "result": {
+          "covered_percent": 84.78
+        }
+      }
+      """
+
 

features/refuse_coverage_drop.feature

@@ -4,7 +4,7 @@ Feature:
   Exit code should be non-zero if the overall coverage decreases.
   And last_run file should not be overwritten with new coverage value.
 
-  Scenario:
+  Scenario: refuse_coverage_drop configured
     Given SimpleCov for Test/Unit is configured with:
       """
       require 'simplecov'
@@ -50,3 +50,46 @@ Feature:
       }
       """
 
+  Scenario: refuse_coverage_drop not configured updates resultset
+    Given SimpleCov for Test/Unit is configured with:
+      """
+      require 'simplecov'
+      SimpleCov.start do
+        add_filter 'test.rb'
+      end
+      """
+
+    When I run `bundle exec rake test`
+    Then the exit status should be 0
+    And a file named "coverage/.last_run.json" should exist
+    And the file "coverage/.last_run.json" should contain:
+      """
+      {
+        "result": {
+          "covered_percent": 88.1
+        }
+      }
+      """
+
+    Given 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
+      """
+
+    When I run `bundle exec rake test`
+    Then the exit status should be 0
+    And a file named "coverage/.last_run.json" should exist
+    And the file "coverage/.last_run.json" should contain:
+      """
+      {
+        "result": {
+          "covered_percent": 84.78
+        }
+      }
+      """

lib/simplecov/defaults.rb

@@ -70,7 +70,6 @@
   if SimpleCov.result? # Result has been computed
     covered_percent = SimpleCov.result.covered_percent.round(2)
     covered_percentages = SimpleCov.result.covered_percentages.map { |p| p.round(2) }
-    coverage_diff = 0
 
     if @exit_status == SimpleCov::ExitCodes::SUCCESS # No other errors
       if covered_percent < SimpleCov.minimum_coverage # rubocop:disable Metrics/BlockNesting
@@ -89,7 +88,7 @@
     end
 
     # Don't overwrite last_run file if refuse_coverage_drop option is enabled and the coverage has dropped
-    unless SimpleCov.refuse_coverage_drop && coverage_diff > 0
+    unless @exit_status == SimpleCov::ExitCodes::MAXIMUM_COVERAGE_DROP
       SimpleCov::LastRun.write(:result => {:covered_percent => covered_percent})
     end
   end