audit: fixes for test checks

Library/Homebrew/dev-cmd/audit.rb

@@ -772,7 +772,7 @@ module Homebrew
       end
       bin_names.each do |name|
         ["system", "shell_output", "pipe_output"].each do |cmd|
-          if text =~ %r{(def test|test do).*(#{Regexp.escape(HOMEBREW_PREFIX)}/bin/)?#{cmd}[\(\s]+['"]#{Regexp.escape(name)}[\s'"]}m
+          if text =~ /test do.*#{cmd}[\(\s]+['"]#{Regexp.escape(name)}[\s'"]/m
             problem %Q(fully scope test #{cmd} calls e.g. #{cmd} "\#{bin}/#{name}")
           end
         end
@@ -803,10 +803,6 @@ module Homebrew
 
       problem "Use separate make calls" if line.include?("make && make")
 
-      if line =~ /shell_output\(['"].+['"], 0\)/
-        problem "Passing 0 to shell_output() is redundant"
-      end
-
       if line =~ /JAVA_HOME/i && !formula.requirements.map(&:class).include?(JavaRequirement)
         problem "Use `depends_on :java` to set JAVA_HOME"
       end

Library/Homebrew/rubocops/class_cop.rb

@@ -22,6 +22,27 @@ module RuboCop
           end
         end
       end
+
+      class TestCalls < FormulaCop
+        def audit_formula(_node, _class_node, _parent_class_node, body_node)
+          test_calls(find_block(body_node, :test)) do |node, params|
+            p1, p2 = params
+            if match = string_content(p1).match(%r{(/usr/local/(s?bin))})
+              offending_node(p1)
+              problem "use \#{#{match[2]}} instead of #{match[1]} in #{node}"
+            end
+
+            if node == :shell_output && node_equals?(p2, 0)
+              offending_node(p2)
+              problem "Passing 0 to shell_output() is redundant"
+            end
+          end
+        end
+
+        def_node_search :test_calls, <<~EOS
+          (send nil? ${:system :shell_output :pipe_output} $...)
+        EOS
+      end
     end
 
     module FormulaAuditStrict