1 files changed, 34 insertions, 0 deletions
diff --git a/spec/ruby/core/kernel/printf_spec.rb b/spec/ruby/core/kernel/printf_spec.rb
new file mode 100644
index 0000000000..b4c68fa449
--- /dev/null
+++ b/spec/ruby/core/kernel/printf_spec.rb
@@ -0,0 +1,34 @@
+require File.expand_path('../../../spec_helper', __FILE__)
+require File.expand_path('../fixtures/classes', __FILE__)
+
+describe "Kernel#printf" do
+  it "is a private method" do
+    Kernel.should have_private_instance_method(:printf)
+  end
+end
+
+describe "Kernel.printf" do
+
+  before :each do
+    @stdout = $stdout
+    @name = tmp("kernel_puts.txt")
+    $stdout = new_io @name
+  end
+
+  after :each do
+    $stdout.close
+    $stdout = @stdout
+    rm_r @name
+  end
+
+  it "writes to stdout when a string is the first argument" do
+    $stdout.should_receive(:write).with("string")
+    Kernel.printf("%s", "string")
+  end
+
+  it "calls write on the first argument when it is not a string" do
+    object = mock('io')
+    object.should_receive(:write).with("string")
+    Kernel.printf(object, "%s", "string")
+  end
+end