Remove redundant configuration keys

rubocop.yml

@@ -24,9 +24,6 @@ Layout/ArgumentAlignment:
 Layout/CaseIndentation:
   EnforcedStyle: end
 
-Layout/EmptyLineAfterGuardClause:
-  Enabled: true
-
 Layout/EndAlignment:
   EnforcedStyleAlignWith: variable
 
@@ -370,9 +367,6 @@ Style/AndOr:
 Style/ArgumentsForwarding:
   Enabled: false
 
-Style/AsciiComments:
-  Enabled: false
-
 Style/BisectedAttrAccessor:
   Enabled: false
 
@@ -439,9 +433,6 @@ Style/EvalWithLocation:
 Style/ExpandPathArguments:
   Enabled: false
 
-Style/ExplicitBlockArgument:
-  Enabled: true
-
 Style/ExponentialNotation:
   Enabled: false
 
@@ -463,9 +454,6 @@ Style/FrozenStringLiteralComment:
     literals will become the default in a future Ruby version, and we want to make
     sure we''re ready.'
 
-Style/GlobalStdStream:
-  Enabled: true
-
 Style/GuardClause:
   Enabled: false
 

test/config_test.rb

@@ -30,4 +30,29 @@ def test_config_is_unchanged
       assert(diff.empty?, error_message)
     end
   end
+
+  def test_config_has_no_redundant_entries
+    config = RuboCop::ConfigLoader.load_file("rubocop.yml")
+    default_config = RuboCop::ConfigLoader.default_configuration
+
+    # This entry is not a cop.
+    config.delete("inherit_mode")
+
+    config.each do |cop_name, cop_config|
+      default_cop_config = default_config.fetch(cop_name)
+      cop_config.each do |key, value|
+        error_message = <<~ERROR
+          Error: #{cop_name} was configured with the same value as the default
+          RuboCop configuration.
+
+          #{cop_name}:
+            #{key}: #{value}
+
+          Please remove the configuration as it is unnecessary.
+        ERROR
+
+        refute_equal(default_cop_config[key], value, error_message)
+      end
+    end
+  end
 end