style: Fix npe and add test for corrected offense results

Library/Homebrew/dev-cmd/audit.rb

@@ -130,7 +130,7 @@ module Homebrew
       formula_count += 1
       problem_count += fa.problems.size
       problem_lines = format_problem_lines(fa.problems)
-      corrected_problem_count = options.fetch(:style_offenses, []).count(&:corrected?)
+      corrected_problem_count = options[:style_offenses].count(&:corrected?)
       new_formula_problem_lines = format_problem_lines(fa.new_formula_problems)
       if args.display_filename?
         puts problem_lines.map { |s| "#{f.path}: #{s}" }

Library/Homebrew/style.rb

@@ -119,7 +119,7 @@ module Homebrew
       end
 
       def file_offenses(path)
-        @file_offenses[path.to_s]
+        @file_offenses.fetch(path.to_s, [])
       end
     end
 

Library/Homebrew/test/cmd/style_spec.rb

@@ -30,6 +30,30 @@ describe "brew style" do
       expect(rubocop_result.file_offenses(formula.realpath.to_s).map(&:message))
         .to include("Extra empty line detected at class body beginning.")
     end
+
+    it "corrected offense output format" do
+      formula = dir/"my-formula-2.rb"
+
+      formula.write <<~EOS
+        class MyFormula2 < Formula
+          desc "Test formula"
+          homepage "https://foo.org"
+          url "https://foo.org/foo-1.7.5.tgz"
+          sha256 "cc692fb9dee0cc288757e708fc1a3b6b56ca1210ca181053a371cb11746969da"
+
+          depends_on "foo"
+          depends_on "bar-config" => :build
+
+          test do
+            assert_equal 5, 5
+          end
+        end
+      EOS
+      options = { fix: true, only_cops: ["NewFormulaAudit/DependencyOrder"], realpath: true }
+      rubocop_result = Homebrew::Style.check_style_json([formula], options)
+      offense_string = rubocop_result.file_offenses(formula.realpath).first.to_s
+      expect(offense_string).to match(/\[Corrected\]/)
+    end
   end
 
   describe "Homebrew::check_style_and_print" do