1 files changed, 76 insertions, 0 deletions
diff --git a/spec/ruby/core/module/prepend_features_spec.rb b/spec/ruby/core/module/prepend_features_spec.rb
new file mode 100644
index 0000000000..6f341804d1
--- /dev/null
+++ b/spec/ruby/core/module/prepend_features_spec.rb
@@ -0,0 +1,76 @@
+require File.expand_path('../../../spec_helper', __FILE__)
+require File.expand_path('../fixtures/classes', __FILE__)
+
+describe "Module#prepend_features" do
+  it "is a private method" do
+    Module.should have_private_instance_method(:prepend_features, true)
+  end
+
+  it "gets called when self is included in another module/class" do
+    ScratchPad.record []
+
+    m = Module.new do
+      def self.prepend_features(mod)
+        ScratchPad << mod
+      end
+    end
+
+    c = Class.new do
+      prepend m
+    end
+
+    ScratchPad.recorded.should == [c]
+  end
+
+  it "raises an ArgumentError on a cyclic prepend" do
+    lambda {
+      ModuleSpecs::CyclicPrepend.send(:prepend_features, ModuleSpecs::CyclicPrepend)
+    }.should raise_error(ArgumentError)
+  end
+
+  it "copies own tainted status to the given module" do
+    other = Module.new
+    Module.new.taint.send :prepend_features, other
+    other.tainted?.should be_true
+  end
+
+  it "copies own untrusted status to the given module" do
+    other = Module.new
+    Module.new.untrust.send :prepend_features, other
+    other.untrusted?.should be_true
+  end
+
+  it "clears caches of the given module" do
+    parent = Class.new do
+      def bar; :bar; end
+    end
+
+    child = Class.new(parent) do
+      def foo; :foo; end
+      def bar; super; end
+    end
+
+    mod = Module.new do
+      def foo; :fooo; end
+    end
+
+    child.new.foo
+    child.new.bar
+
+    child.prepend(mod)
+
+    child.new.bar.should == :bar
+  end
+
+  describe "on Class" do
+    it "is undefined" do
+      Class.should_not have_private_instance_method(:prepend_features, true)
+    end
+
+    it "raises a TypeError if calling after rebinded to Class" do
+      lambda {
+        Module.instance_method(:prepend_features).bind(Class.new).call Module.new
+      }.should raise_error(TypeError)
+    end
+  end
+end