1 files changed, 56 insertions, 0 deletions
diff --git a/spec/ruby/core/kernel/is_a_spec.rb b/spec/ruby/core/kernel/is_a_spec.rb
new file mode 100644
index 0000000000..ff36a769c7
--- /dev/null
+++ b/spec/ruby/core/kernel/is_a_spec.rb
@@ -0,0 +1,56 @@
+require_relative '../../spec_helper'
+require_relative 'fixtures/classes'
+
+describe "Kernel#is_a?" do
+  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