1 files changed, 26 insertions, 12 deletions
diff --git a/spec/ruby/library/stringio/shared/write.rb b/spec/ruby/library/stringio/shared/write.rb
index d9c21028e0..4661658baf 100644
--- a/spec/ruby/library/stringio/shared/write.rb
+++ b/spec/ruby/library/stringio/shared/write.rb
@@ -1,6 +1,6 @@
 describe :stringio_write, shared: true do
   before :each do
-    @io = StringIO.new('12345')
+    @io = StringIO.new(+'12345')
   end
 
   it "tries to convert the passed Object to a String using #to_s" do
@@ -13,7 +13,7 @@ end
 
 describe :stringio_write_string, shared: true do
   before :each do
-    @io = StringIO.new('12345')
+    @io = StringIO.new(+'12345')
   end
 
   # TODO: RDoc says that #write appends at the current position.
@@ -60,13 +60,6 @@ describe :stringio_write_string, shared: true do
     @io.string.size.should == n.times.map(&:to_s).join.size
   end
 
-  ruby_version_is ""..."3.0" do
-    it "does not taint self when the passed argument is tainted" do
-      @io.send(@method, "test".taint)
-      @io.tainted?.should be_false
-    end
-  end
-
   it "handles writing non-ASCII UTF-8 after seek" do
     @io.binmode
     @io << "\x80"
@@ -88,14 +81,35 @@ describe :stringio_write_string, shared: true do
     @io.write "fghi"
     @io.string.should == "12fghi"
   end
+
+  it "transcodes the given string when the external encoding is set and neither is BINARY" do
+    utf8_str = "hello"
+    io = StringIO.new.set_encoding(Encoding::UTF_16BE)
+    io.external_encoding.should == Encoding::UTF_16BE
+
+    io.send(@method, utf8_str)
+
+    expected = [0, 104, 0, 101, 0, 108, 0, 108, 0, 111] # UTF-16BE bytes for "hello"
+    io.string.bytes.should == expected
+  end
+
+  it "does not transcode the given string when the external encoding is set and the string encoding is BINARY" do
+    str = "été_".b
+    io = StringIO.new.set_encoding(Encoding::UTF_16BE)
+    io.external_encoding.should == Encoding::UTF_16BE
+
+    io.send(@method, str)
+
+    io.string.bytes.should == str.bytes
+  end
 end
 
 describe :stringio_write_not_writable, shared: true do
   it "raises an IOError" do
-    io = StringIO.new("test", "r")
+    io = StringIO.new(+"test", "r")
     -> { io.send(@method, "test") }.should raise_error(IOError)
 
-    io = StringIO.new("test")
+    io = StringIO.new(+"test")
     io.close_write
     -> { io.send(@method, "test") }.should raise_error(IOError)
   end
@@ -103,7 +117,7 @@ end
 
 describe :stringio_write_append, shared: true do
   before :each do
-    @io = StringIO.new("example", "a")
+    @io = StringIO.new(+"example", "a")
   end
 
   it "appends the passed argument to the end of self" do