1 files changed, 33 insertions, 2 deletions
diff --git a/spec/ruby/core/module/module_exec_spec.rb b/spec/ruby/core/module/module_exec_spec.rb
index 47cdf7ef52..6b36e8a02f 100644
--- a/spec/ruby/core/module/module_exec_spec.rb
+++ b/spec/ruby/core/module/module_exec_spec.rb
@@ -1,7 +1,38 @@
 require_relative '../../spec_helper'
 require_relative 'fixtures/classes'
-require_relative 'shared/class_exec'
 
 describe "Module#module_exec" do
-  it_behaves_like :module_class_exec, :module_exec
+  it "does not add defined methods to other classes" do
+    FalseClass.module_exec do
+      def foo
+        'foo'
+      end
+    end
+    -> {42.foo}.should.raise(NoMethodError)
+  end
+
+  it "defines method in the receiver's scope" do
+    ModuleSpecs::Subclass.module_exec { def foo; end }
+    ModuleSpecs::Subclass.new.respond_to?(:foo).should == true
+  end
+
+  it "evaluates a given block in the context of self" do
+    ModuleSpecs::Subclass.module_exec { self }.should == ModuleSpecs::Subclass
+    ModuleSpecs::Subclass.new.module_exec { 1 + 1 }.should == 2
+  end
+
+  it "raises a LocalJumpError when no block is given" do
+    -> { ModuleSpecs::Subclass.module_exec }.should.raise(LocalJumpError)
+  end
+
+  it "passes arguments to the block" do
+    a = ModuleSpecs::Subclass
+    a.module_exec(1) { |b| b }.should.equal?(1)
+  end
+
+  describe "with optional argument" do
+    it "does not destructure a single array argument" do
+      ModuleSpecs::Subclass.module_exec([1, 2, 3]) { |a = 99| a }.should == [1, 2, 3]
+    end
+  end
 end