1 files changed, 52 insertions, 2 deletions
diff --git a/spec/ruby/core/kernel/is_a_spec.rb b/spec/ruby/core/kernel/is_a_spec.rb
index dc69766f83..ff36a769c7 100644
--- a/spec/ruby/core/kernel/is_a_spec.rb
+++ b/spec/ruby/core/kernel/is_a_spec.rb
@@ -1,6 +1,56 @@
 require_relative '../../spec_helper'
-require_relative 'shared/kind_of'
+require_relative 'fixtures/classes'
 
 describe "Kernel#is_a?" do
-  it_behaves_like :kernel_kind_of , :is_a?
+  before :each do
+    @o = KernelSpecs::KindaClass.new
+  end
+
+  it "returns true if given class is the object's class" do
+    @o.is_a?(KernelSpecs::KindaClass).should == true
+  end
+
+  it "returns true if given class is an ancestor of the object's class" do
+    @o.is_a?(KernelSpecs::AncestorClass).should == true
+    @o.is_a?(String).should == true
+    @o.is_a?(Object).should == true
+  end
+
+  it "returns false if the given class is not object's class nor an ancestor" do
+    @o.is_a?(Array).should == false
+  end
+
+  it "returns true if given a Module that is included in object's class" do
+    @o.is_a?(KernelSpecs::MyModule).should == true
+  end
+
+  it "returns true if given a Module that is included one of object's ancestors only" do
+    @o.is_a?(KernelSpecs::AncestorModule).should == true
+  end
+
+  it "returns true if given a Module that object has been extended with" do
+    @o.is_a?(KernelSpecs::MyExtensionModule).should == true
+  end
+
+  it "returns true if given a Module that object has been prepended with" do
+    @o.is_a?(KernelSpecs::MyPrependedModule).should == true
+  end
+
+  it "returns false if given a Module not included nor prepended in object's class nor ancestors" do
+    @o.is_a?(KernelSpecs::SomeOtherModule).should == false
+  end
+
+  it "raises a TypeError if given an object that is not a Class nor a Module" do
+    -> { @o.is_a?(1) }.should.raise(TypeError)
+    -> { @o.is_a?('KindaClass') }.should.raise(TypeError)
+    -> { @o.is_a?(:KindaClass) }.should.raise(TypeError)
+    -> { @o.is_a?(Object.new) }.should.raise(TypeError)
+  end
+
+  it "does not take into account `class` method overriding" do
+    def @o.class; Integer; end
+
+    @o.is_a?(Integer).should == false
+    @o.is_a?(KernelSpecs::KindaClass).should == true
+  end
 end