1 files changed, 51 insertions, 0 deletions
diff --git a/test/-ext-/thread/helper.rb b/test/-ext-/thread/helper.rb
new file mode 100644
index 0000000000..3ea2057d15
--- /dev/null
+++ b/test/-ext-/thread/helper.rb
@@ -0,0 +1,51 @@
+module ThreadInstrumentation
+  module TestHelper
+    private
+
+    def record
+      Bug::ThreadInstrumentation.register_callback(!ENV["GVL_DEBUG"])
+      yield
+    ensure
+      timeline = Bug::ThreadInstrumentation.unregister_callback
+      if $!
+        raise
+      else
+        return timeline
+      end
+    end
+
+    def timeline_for(thread, timeline)
+      timeline.select { |t, _| t == thread }.map(&:last)
+    end
+
+    def assert_consistent_timeline(events)
+      refute_predicate events, :empty?
+
+      previous_event = nil
+      events.each do |event|
+        refute_equal :exited, previous_event, "`exited` must be the final event: #{events.inspect}"
+        case event
+        when :started
+          assert_nil previous_event, "`started` must be the first event: #{events.inspect}"
+        when :ready
+          unless previous_event.nil?
+            assert %i(started suspended).include?(previous_event), "`ready` must be preceded by `started` or `suspended`: #{events.inspect}"
+          end
+        when :resumed
+          unless previous_event.nil?
+            assert_equal :ready, previous_event, "`resumed` must be preceded by `ready`: #{events.inspect}"
+          end
+        when :suspended
+          unless previous_event.nil?
+            assert_equal :resumed, previous_event, "`suspended` must be preceded by `resumed`: #{events.inspect}"
+          end
+        when :exited
+          unless previous_event.nil?
+            assert %i(resumed suspended).include?(previous_event), "`exited` must be preceded by `resumed` or `suspended`: #{events.inspect}"
+          end
+        end
+        previous_event = event
+      end
+    end
+  end
+end