1 files changed, 16 insertions, 0 deletions
diff --git a/spec/ruby/core/string/b_spec.rb b/spec/ruby/core/string/b_spec.rb
new file mode 100644
index 0000000000..4b1fafff11
--- /dev/null
+++ b/spec/ruby/core/string/b_spec.rb
@@ -0,0 +1,16 @@
+# -*- encoding: utf-8 -*-
+# frozen_string_literal: false
+require_relative '../../spec_helper'
+
+describe "String#b" do
+  it "returns a binary encoded string" do
+    "Hello".b.should == "Hello".force_encoding(Encoding::BINARY)
+    "こんちには".b.should == "こんちには".force_encoding(Encoding::BINARY)
+  end
+
+  it "returns new string without modifying self" do
+    str = "こんちには"
+    str.b.should_not equal(str)
+    str.should == "こんちには"
+  end
+end