1 files changed, 39 insertions, 0 deletions
diff --git a/spec/ruby/core/threadgroup/add_spec.rb b/spec/ruby/core/threadgroup/add_spec.rb
new file mode 100644
index 0000000000..2921c1ab22
--- /dev/null
+++ b/spec/ruby/core/threadgroup/add_spec.rb
@@ -0,0 +1,39 @@
+require_relative '../../spec_helper'
+
+describe "ThreadGroup#add" do
+  before :each do
+    @q1, @q2 = Queue.new, Queue.new
+    @thread = Thread.new { @q1 << :go; @q2.pop }
+    @q1.pop
+  end
+
+  after :each do
+    @q2 << :done
+    @thread.join
+  end
+
+  # This spec randomly kills mspec worker like: https://ci.appveyor.com/project/ruby/ruby/build/9806/job/37tx2atojy96227m
+  # TODO: Investigate the cause or at least print helpful logs, and remove this `platform_is_not` guard.
+  platform_is_not :mingw do
+    it "adds the given thread to a group and returns self" do
+      @thread.group.should_not == nil
+
+      tg = ThreadGroup.new
+      tg.add(@thread).should == tg
+      @thread.group.should == tg
+      tg.list.include?(@thread).should == true
+    end
+
+    it "removes itself from any other threadgroup" do
+      tg1 = ThreadGroup.new
+      tg2 = ThreadGroup.new
+
+      tg1.add(@thread)
+      @thread.group.should == tg1
+      tg2.add(@thread)
+      @thread.group.should == tg2
+      tg2.list.include?(@thread).should == true
+      tg1.list.include?(@thread).should == false
+    end
+  end
+end