audit: avoid build-time checks in core

Co-Authored-By: Mike McQuaid <mike@mikemcquaid.com>

Library/Homebrew/rubocops/lines.rb

@@ -419,6 +419,21 @@ module RuboCop
 
             problem "Use the `#{match}` Ruby method instead of `#{method.source}`"
           end
+
+          return if formula_tap != "homebrew-core"
+
+          # Avoid build-time checks in homebrew/core
+          find_every_method_call_by_name(body_node, :system).each do |method|
+            params = parameters(method)
+            next unless node_equals?(params[0], "make")
+
+            params[1..].each do |arg|
+              next unless regex_match_group(arg, /^(checks?|tests?)$/)
+
+              offending_node(method)
+              problem "Formulae in homebrew/core should not run build-time checks"
+            end
+          end
         end
 
         def modifier?(node)

Library/Homebrew/test/rubocops/lines_spec.rb

@@ -349,6 +349,17 @@ describe RuboCop::Cop::FormulaAudit::Miscellaneous do
   subject(:cop) { described_class.new }
 
   context "When auditing formula" do
+    it "build-time checks in homebrew/core" do
+      expect_offense(<<~RUBY, "/homebrew-core/")
+        class Foo < Formula
+          desc "foo"
+          url 'https://brew.sh/foo-1.0.tgz'
+          system "make", "-j1", "test"
+          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Formulae in homebrew/core should not run build-time checks
+        end
+      RUBY
+    end
+
     it "FileUtils usage" do
       expect_offense(<<~RUBY)
         class Foo < Formula