1 files changed, 49 insertions, 2 deletions
diff --git a/actionview/test/template/erb_util_test.rb b/actionview/test/template/erb_util_test.rb
index 3e5b029cea..3e72be31de 100644
--- a/actionview/test/template/erb_util_test.rb
+++ b/actionview/test/template/erb_util_test.rb
@@ -1,4 +1,5 @@
 require 'abstract_unit'
+require 'active_support/json'
 
 class ErbUtilTest < ActiveSupport::TestCase
   include ERB::Util
@@ -15,6 +16,51 @@ class ErbUtilTest < ActiveSupport::TestCase
     end
   end
 
+  HTML_ESCAPE_TEST_CASES = [
+    ['<br>', '&lt;br&gt;'],
+    ['a & b', 'a &amp; b'],
+    ['"quoted" string', '&quot;quoted&quot; string'],
+    ["'quoted' string", '&#39;quoted&#39; string'],
+    [
+      '<script type="application/javascript">alert("You are \'pwned\'!")</script>',
+      '&lt;script type=&quot;application/javascript&quot;&gt;alert(&quot;You are &#39;pwned&#39;!&quot;)&lt;/script&gt;'
+    ]
+  ]
+
+  JSON_ESCAPE_TEST_CASES = [
+    ['1', '1'],
+    ['null', 'null'],
+    ['"&"', '"\u0026"'],
+    ['"</script>"', '"\u003c/script\u003e"'],
+    ['["</script>"]', '["\u003c/script\u003e"]'],
+    ['{"name":"</script>"}', '{"name":"\u003c/script\u003e"}'],
+    [%({"name":"d\u2028h\u2029h"}), '{"name":"d\u2028h\u2029h"}']
+  ]
+
+  def test_html_escape
+    HTML_ESCAPE_TEST_CASES.each do |(raw, expected)|
+      assert_equal expected, html_escape(raw)
+    end
+  end
+
+  def test_json_escape
+    JSON_ESCAPE_TEST_CASES.each do |(raw, expected)|
+      assert_equal expected, json_escape(raw)
+    end
+  end
+
+  def test_json_escape_does_not_alter_json_string_meaning
+    JSON_ESCAPE_TEST_CASES.each do |(raw, _)|
+      assert_equal ActiveSupport::JSON.decode(raw), ActiveSupport::JSON.decode(json_escape(raw))
+    end
+  end
+
+  def test_json_escape_is_idempotent
+    JSON_ESCAPE_TEST_CASES.each do |(raw, _)|
+      assert_equal json_escape(raw), json_escape(json_escape(raw))
+    end
+  end
+
   def test_json_escape_returns_unsafe_strings_when_passed_unsafe_strings
     value = json_escape("asdf")
     assert !value.html_safe?
@@ -31,14 +77,14 @@ class ErbUtilTest < ActiveSupport::TestCase
     assert escaped.html_safe?
   end
 
-  def test_html_escape_passes_html_escpe_unmodified
+  def test_html_escape_passes_html_escape_unmodified
     escaped = h("<p>".html_safe)
     assert_equal "<p>", escaped
     assert escaped.html_safe?
   end
 
   def test_rest_in_ascii
-    (0..127).to_a.map {|int| int.chr }.each do |chr|
+    (0..127).to_a.map(&:chr).each do |chr|
       next if %('"&<>).include?(chr)
       assert_equal chr, html_escape(chr)
     end
@@ -46,6 +92,7 @@ class ErbUtilTest < ActiveSupport::TestCase
 
   def test_html_escape_once
     assert_equal '1 &lt;&gt;&amp;&quot;&#39; 2 &amp; 3', html_escape_once('1 <>&"\' 2 &amp; 3')
+    assert_equal " &#X27; &#x27; &#x03BB; &#X03bb; &quot; &#39; &lt; &gt; ", html_escape_once(" &#X27; &#x27; &#x03BB; &#X03bb; \" ' < > ")
   end
 
   def test_html_escape_once_returns_unsafe_strings_when_passed_unsafe_strings