1 files changed, 17 insertions, 5 deletions
diff --git a/activesupport/test/gzip_test.rb b/activesupport/test/gzip_test.rb
index 0e3cf3b429..05ce12fe86 100644
--- a/activesupport/test/gzip_test.rb
+++ b/activesupport/test/gzip_test.rb
@@ -1,5 +1,7 @@
-require 'abstract_unit'
-require 'active_support/core_ext/object/blank'
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/core_ext/object/blank"
 
 class GzipTest < ActiveSupport::TestCase
   def test_compress_should_decompress_to_the_same_value
@@ -13,14 +15,14 @@ class GzipTest < ActiveSupport::TestCase
   end
 
   def test_compress_should_return_a_binary_string
-    compressed = ActiveSupport::Gzip.compress('')
+    compressed = ActiveSupport::Gzip.compress("")
 
-    assert_equal Encoding.find('binary'), compressed.encoding
+    assert_equal Encoding.find("binary"), compressed.encoding
     assert !compressed.blank?, "a compressed blank string should not be blank"
   end
 
   def test_compress_should_return_gzipped_string_by_compression_level
-    source_string = "Hello World"*100
+    source_string = "Hello World" * 100
 
     gzipped_by_speed = ActiveSupport::Gzip.compress(source_string, Zlib::BEST_SPEED)
     assert_equal 1, Zlib::GzipReader.new(StringIO.new(gzipped_by_speed)).level
@@ -30,4 +32,14 @@ class GzipTest < ActiveSupport::TestCase
 
     assert_equal true, (gzipped_by_best_compression.bytesize < gzipped_by_speed.bytesize)
   end
+
+  def test_decompress_checks_crc
+    compressed = ActiveSupport::Gzip.compress("Hello World")
+    first_crc_byte_index = compressed.bytesize - 8
+    compressed.setbyte(first_crc_byte_index, compressed.getbyte(first_crc_byte_index) ^ 0xff)
+
+    assert_raises(Zlib::GzipFile::CRCError) do
+      ActiveSupport::Gzip.decompress(compressed)
+    end
+  end
 end