Add test for top level method def

Library/Homebrew/rubocops/extend/formula_cop.rb

@@ -232,6 +232,7 @@ module RuboCop
           @offense_source_range = def_node.source_range
           return def_node
         end
+        return if node.parent.nil?
         # If not found then, parent node becomes the offensive node
         @offensive_node = node.parent
         @offense_source_range = node.parent.source_range

Library/Homebrew/rubocops/lines_cop.rb

@@ -271,9 +271,9 @@ module RuboCop
             problem "Use the `#{match}` Ruby method instead of `#{m.source}`"
           end
 
-          # if find_method_def(@processed_source.ast)
-          #   problem "Define method #{method_name(@offensive_node)} in the class body, not at the top-level"
-          # end
+          if find_method_def(@processed_source.ast)
+            problem "Define method #{method_name(@offensive_node)} in the class body, not at the top-level"
+          end
           #
           # find_instance_method_call(body_node, :build, :without?) do |m|
           #   next unless unless_modifier?(m.parent)

Library/Homebrew/test/rubocops/lines_cop_spec.rb

@@ -592,6 +592,29 @@ describe RuboCop::Cop::FormulaAudit::Miscellaneous do
 
       inspect_source(cop, source)
 
+      expected_offenses.zip(cop.offenses).each do |expected, actual|
+        expect_offense(expected, actual)
+      end
+    end
+    it "with a top-level function def " do
+      source = <<-EOS.undent
+        def test
+           nil
+        end
+        class Foo < Formula
+          desc "foo"
+          url 'http://example.com/foo-1.0.tgz'
+        end
+      EOS
+
+      expected_offenses = [{  message: "Define method test in the class body, not at the top-level",
+                              severity: :convention,
+                              line: 1,
+                              column: 0,
+                              source: source }]
+
+      inspect_source(cop, source)
+
       expected_offenses.zip(cop.offenses).each do |expected, actual|
         expect_offense(expected, actual)
       end