1 files changed, 70 insertions, 0 deletions
diff --git a/spec/ruby/core/module/ancestors_spec.rb b/spec/ruby/core/module/ancestors_spec.rb
new file mode 100644
index 0000000000..1cd537f7a0
--- /dev/null
+++ b/spec/ruby/core/module/ancestors_spec.rb
@@ -0,0 +1,70 @@
+require File.expand_path('../../../spec_helper', __FILE__)
+require File.expand_path('../fixtures/classes', __FILE__)
+
+describe "Module#ancestors" do
+  it "returns a list of modules included in self (including self)" do
+    BasicObject.ancestors.should == [BasicObject]
+    ModuleSpecs.ancestors.should == [ModuleSpecs]
+    ModuleSpecs::Basic.ancestors.should == [ModuleSpecs::Basic]
+    ModuleSpecs::Super.ancestors.should == [ModuleSpecs::Super, ModuleSpecs::Basic]
+    ModuleSpecs.without_test_modules(ModuleSpecs::Parent.ancestors).should ==
+      [ModuleSpecs::Parent, Object, Kernel, BasicObject]
+    ModuleSpecs.without_test_modules(ModuleSpecs::Child.ancestors).should ==
+      [ModuleSpecs::Child, ModuleSpecs::Super, ModuleSpecs::Basic, ModuleSpecs::Parent, Object, Kernel, BasicObject]
+  end
+
+  it "returns only modules and classes" do
+    class << ModuleSpecs::Child; self; end.ancestors.should include(ModuleSpecs::Internal, Class, Module, Object, Kernel)
+  end
+
+  it "has 1 entry per module or class" do
+    ModuleSpecs::Parent.ancestors.should == ModuleSpecs::Parent.ancestors.uniq
+  end
+
+  describe "when called on a singleton class" do
+    it "includes the singleton classes of ancestors" do
+      parent  = Class.new
+      child   = Class.new(parent)
+      schild  = child.singleton_class
+
+      schild.ancestors.should include(schild,
+                                      parent.singleton_class,
+                                      Object.singleton_class,
+                                      BasicObject.singleton_class,
+                                      Class,
+                                      Module,
+                                      Object,
+                                      Kernel,
+                                      BasicObject)
+
+    end
+
+    describe 'for a standalone module' do
+      it 'does not include Class' do
+        s_mod = ModuleSpecs.singleton_class
+        s_mod.ancestors.should_not include(Class)
+      end
+
+      it 'does not include other singleton classes' do
+        s_standalone_mod = ModuleSpecs.singleton_class
+        s_module = Module.singleton_class
+        s_object = Object.singleton_class
+        s_basic_object = BasicObject.singleton_class
+
+        s_standalone_mod.ancestors.should_not include(s_module, s_object, s_basic_object)
+      end
+
+      it 'includes its own singleton class' do
+        s_mod = ModuleSpecs.singleton_class
+
+        s_mod.ancestors.should include(s_mod)
+      end
+
+      it 'includes standard chain' do
+        s_mod = ModuleSpecs.singleton_class
+
+        s_mod.ancestors.should include(Module, Object, Kernel, BasicObject)
+      end
+    end
+  end
+end