1 files changed, 19 insertions, 0 deletions
diff --git a/test/ruby/test_string.rb b/test/ruby/test_string.rb
new file mode 100644
index 000000000..0ce33fdf1
--- /dev/null
+++ b/test/ruby/test_string.rb
@@ -0,0 +1,19 @@
+require 'test/unit'
+
+class TestString < Test::Unit::TestCase
+  def check_sum(str, bits=16)
+    sum = 0
+    str.each_byte {|c| sum += c}
+    sum = sum & ((1 << bits) - 1) if bits != 0
+    assert_equal(sum, str.sum(bits))
+  end
+  def test_sum
+    assert_equal(0, "".sum)
+    assert_equal(294, "abc".sum)
+    check_sum("abc")
+    check_sum("\x80")
+    8.upto(70) {|bits|
+      check_sum("xyz", bits)
+    }
+  end
+end