1 files changed, 24 insertions, 21 deletions
diff --git a/spec/ruby/core/threadgroup/add_spec.rb b/spec/ruby/core/threadgroup/add_spec.rb
index 4320f7ba30..2921c1ab22 100644
--- a/spec/ruby/core/threadgroup/add_spec.rb
+++ b/spec/ruby/core/threadgroup/add_spec.rb
@@ -1,36 +1,39 @@
 require_relative '../../spec_helper'
-require_relative 'fixtures/classes'
 
 describe "ThreadGroup#add" do
   before :each do
-    @chan1,@chan2 = Channel.new,Channel.new
-    @thread = Thread.new { @chan1 << :go; @chan2.receive }
-    @chan1.receive
+    @q1, @q2 = Queue.new, Queue.new
+    @thread = Thread.new { @q1 << :go; @q2.pop }
+    @q1.pop
   end
 
   after :each do
-    @chan2 << :done
+    @q2 << :done
     @thread.join
   end
 
-  it "adds the given thread to a group and returns self" do
-    @thread.group.should_not == nil
+  # 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
+      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
+    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
+      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