1 files changed, 19 insertions, 1 deletions
diff --git a/spec/ruby/library/stringio/readlines_spec.rb b/spec/ruby/library/stringio/readlines_spec.rb
index 4b007787e2..ed7cc22b3d 100644
--- a/spec/ruby/library/stringio/readlines_spec.rb
+++ b/spec/ruby/library/stringio/readlines_spec.rb
@@ -83,7 +83,7 @@ end
 
 describe "StringIO#readlines when in write-only mode" do
   it "raises an IOError" do
-    io = StringIO.new("xyz", "w")
+    io = StringIO.new(+"xyz", "w")
     -> { io.readlines }.should raise_error(IOError)
 
     io = StringIO.new("xyz")
@@ -98,3 +98,21 @@ describe "StringIO#readlines when passed [chomp]" do
     io.readlines(chomp: true).should == ["this>is", "an>example"]
   end
 end
+
+describe "StringIO#readlines when passed [limit]" do
+  before :each do
+    @io = StringIO.new("a b c d e\n1 2 3 4 5")
+  end
+
+  it "returns the data read until the limit is met" do
+    @io.readlines(4).should == ["a b ", "c d ", "e\n", "1 2 ", "3 4 ", "5"]
+  end
+
+  it "raises ArgumentError when limit is 0" do
+    -> { @io.readlines(0) }.should raise_error(ArgumentError)
+  end
+
+  it "ignores it when the limit is negative" do
+    @io.readlines(-4).should == ["a b c d e\n", "1 2 3 4 5"]
+  end
+end