Cache Jekyll.sanitized_path (#8424)

Merge pull request 8424

test/test_path_manager.rb

@@ -0,0 +1,35 @@
+# frozen_string_literal: true
+
+require "helper"
+
+class TestPathManager < JekyllUnitTest
+  context "PathManager" do
+    setup do
+      @source = Dir.pwd
+    end
+
+    should "return frozen copy of base if questionable path is nil" do
+      assert_equal @source, Jekyll::PathManager.sanitized_path(@source, nil)
+      assert Jekyll::PathManager.sanitized_path(@source, nil).frozen?
+    end
+
+    should "return a frozen copy of base if questionable path expands into the base" do
+      assert_equal @source, Jekyll::PathManager.sanitized_path(@source, File.join(@source, "/"))
+      assert Jekyll::PathManager.sanitized_path(@source, File.join(@source, "/")).frozen?
+    end
+
+    should "return a frozen string result" do
+      if Jekyll::Utils::Platforms.really_windows?
+        assert_equal(
+          "#{@source}/_config.yml",
+          Jekyll::PathManager.sanitized_path(@source, "E:\\_config.yml")
+        )
+      end
+      assert_equal(
+        "#{@source}/_config.yml",
+        Jekyll::PathManager.sanitized_path(@source, "//_config.yml")
+      )
+      assert Jekyll::PathManager.sanitized_path(@source, "//_config.yml").frozen?
+    end
+  end
+end