testing_env: needs_compat utility added

Closes Homebrew/homebrew#48302.

Signed-off-by: Baptiste Fontaine <batifon@yahoo.fr>

Library/Homebrew/test/test_cmd_audit.rb

@@ -216,6 +216,9 @@ class FormulaAuditorTests < Homebrew::TestCase
   end
 
   def test_audit_class_github_gist_formula
+    needs_compat
+    require "compat/formula_specialties"
+
     fa = formula_auditor "foo", <<-EOS.undent
       class Foo < GithubGistFormula
         url "http://example.com/foo-1.0.tgz"
@@ -227,6 +230,9 @@ class FormulaAuditorTests < Homebrew::TestCase
   end
 
   def test_audit_class_script_file_formula
+    needs_compat
+    require "compat/formula_specialties"
+
     fa = formula_auditor "foo", <<-EOS.undent
       class Foo < ScriptFileFormula
         url "http://example.com/foo-1.0.tgz"
@@ -238,6 +244,9 @@ class FormulaAuditorTests < Homebrew::TestCase
   end
 
   def test_audit_class_aws_formula
+    needs_compat
+    require "compat/formula_specialties"
+
     fa = formula_auditor "foo", <<-EOS.undent
       class Foo < AmazonWebServicesFormula
         url "http://example.com/foo-1.0.tgz"

Library/Homebrew/test/testing_env.rb

@@ -93,6 +93,10 @@ module Homebrew
       Dir.mktmpdir(prefix_suffix, HOMEBREW_TEMP, &block)
     end
 
+    def needs_compat
+      skip "Requires compat/ code" if ENV["HOMEBREW_NO_COMPAT"]
+    end
+
     def assert_nothing_raised
       yield
     end