1 files changed, 73 insertions, 0 deletions
diff --git a/spec/ruby/core/module/append_features_spec.rb b/spec/ruby/core/module/append_features_spec.rb
new file mode 100644
index 0000000000..ceb8c3f8eb
--- /dev/null
+++ b/spec/ruby/core/module/append_features_spec.rb
@@ -0,0 +1,73 @@
+require File.expand_path('../../../spec_helper', __FILE__)
+require File.expand_path('../fixtures/classes', __FILE__)
+
+describe "Module#append_features" do
+  it "is a private method" do
+    Module.should have_private_instance_method(:append_features)
+  end
+
+  describe "on Class" do
+    it "is undefined" do
+      Class.should_not have_private_instance_method(:append_features, true)
+    end
+
+    it "raises a TypeError if calling after rebinded to Class" do
+      lambda {
+        Module.instance_method(:append_features).bind(Class.new).call Module.new
+      }.should raise_error(TypeError)
+    end
+  end
+
+  it "gets called when self is included in another module/class" do
+    begin
+      m = Module.new do
+        def self.append_features(mod)
+          $appended_to = mod
+        end
+      end
+
+      c = Class.new do
+        include m
+      end
+
+      $appended_to.should == c
+    ensure
+      $appended_to = nil
+    end
+  end
+
+  it "raises an ArgumentError on a cyclic include" do
+    lambda {
+      ModuleSpecs::CyclicAppendA.send(:append_features, ModuleSpecs::CyclicAppendA)
+    }.should raise_error(ArgumentError)
+
+    lambda {
+      ModuleSpecs::CyclicAppendB.send(:append_features, ModuleSpecs::CyclicAppendA)
+    }.should raise_error(ArgumentError)
+
+  end
+
+  it "copies own tainted status to the given module" do
+    other = Module.new
+    Module.new.taint.send :append_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 :append_features, other
+    other.untrusted?.should be_true
+  end
+
+  describe "when other is frozen" do
+    before :each do
+      @receiver = Module.new
+      @other = Module.new.freeze
+    end
+
+    it "raises a RuntimeError before appending self" do
+      lambda { @receiver.send(:append_features, @other) }.should raise_error(RuntimeError)
+      @other.ancestors.should_not include(@receiver)
+    end
+  end
+end