1 files changed, 32 insertions, 0 deletions
diff --git a/spec/ruby/core/io/printf_spec.rb b/spec/ruby/core/io/printf_spec.rb
new file mode 100644
index 0000000000..baa00f14ce
--- /dev/null
+++ b/spec/ruby/core/io/printf_spec.rb
@@ -0,0 +1,32 @@
+require_relative '../../spec_helper'
+require_relative 'fixtures/classes'
+
+describe "IO#printf" do
+  before :each do
+    @name = tmp("io_printf.txt")
+    @io = new_io @name
+    @io.sync = true
+  end
+
+  after :each do
+    @io.close if @io
+    rm_r @name
+  end
+
+  it "calls #to_str to convert the format object to a String" do
+    obj = mock("printf format")
+    obj.should_receive(:to_str).and_return("%s")
+
+    @io.printf obj, "printf"
+    File.read(@name).should == "printf"
+  end
+
+  it "writes the #sprintf formatted string" do
+    @io.printf "%d %s", 5, "cookies"
+    File.read(@name).should == "5 cookies"
+  end
+
+  it "raises IOError on closed stream" do
+    -> { IOSpecs.closed_io.printf("stuff") }.should raise_error(IOError)
+  end
+end