diff --git a/core/io/select_spec.rb b/core/io/select_spec.rb
index 3893e7620..9fdb7e12c 100644
--- a/core/io/select_spec.rb
+++ b/core/io/select_spec.rb
@@ -149,16 +149,28 @@
   end
 end
 
-describe "IO.select when passed nil for timeout" do
-  it "sleeps forever and sets the thread status to 'sleep'" do
-    t = Thread.new do
-      IO.select(nil, nil, nil, nil)
+describe "IO.select with infinite timeout" do
+  describe :io_select_infinite_timeout, shared: true do
+    it "sleeps forever and sets the thread status to 'sleep'" do
+      t = Thread.new do
+        IO.select(nil, nil, nil, @method)
+      end
+
+      Thread.pass while t.status && t.status != "sleep"
+      t.join unless t.status
+      t.status.should == "sleep"
+      t.kill
+      t.join
     end
+  end
 
-    Thread.pass while t.status && t.status != "sleep"
-    t.join unless t.status
-    t.status.should == "sleep"
-    t.kill
-    t.join
+  describe "IO.select when passed nil for timeout" do
+    it_behaves_like :io_select_infinite_timeout, nil
+  end
+
+  ruby_version_is "4.0" do
+    describe "IO.select when passed Float::INFINITY for timeout" do
+      it_behaves_like :io_select_infinite_timeout, Float::INFINITY
+    end
   end
 end