fix: register a promise as waiting_work only if it is being executed

lib/roby/promise.rb

@@ -39,7 +39,6 @@ def initialize(
             executor: execution_engine.thread_pool, description: "promise", &block
         )
             @execution_engine = execution_engine
-            execution_engine.waiting_work << self
             @description = description
 
             @pipeline = []
@@ -260,6 +259,7 @@ def fail(exception = StandardError)
         end
 
         def execute
+            execution_engine.waiting_work << self
             promise.execute
             self
         end

test/test_execution_engine.rb

@@ -99,8 +99,13 @@ module Roby
         end
 
         describe "promise handling" do
-            it "queues promises in the #waiting_work list" do
+            it "does not queue a promise in #waiting_work on creation" do
                 p = execution_engine.promise {}
+                refute execution_engine.waiting_work.include?(p)
+            end
+
+            it "queues a promise in #waiting_work on execution" do
+                p = execution_engine.promise {}.execute
                 assert execution_engine.waiting_work.include?(p)
             end
 

test/test_promise.rb

@@ -9,10 +9,6 @@ module Roby
         before do
             @recorder = flexmock
         end
-        it "registers the promise as pending work on the engine" do
-            p = execution_engine.promise {}
-            assert execution_engine.waiting_work.include?(p)
-        end
 
         it "executes the promised work" do
             recorder.should_receive(:called).once