Merge pull request #1358 from mbj/change/to-faster-signal

Change to more efficient worker termination

lib/mutant/parallel/driver.rb

@@ -49,6 +49,7 @@ def stop
       def finalize(status)
         status.tap do
           if status.done?
+            workers.each(&:signal)
             workers.each(&:join)
             threads.each(&:join)
           end

lib/mutant/parallel/worker.rb

@@ -77,8 +77,12 @@ def call
         self
       end
 
-      def join
+      def signal
         process.kill('TERM', pid)
+        self
+      end
+
+      def join
         process.wait(pid)
         self
       end

spec/unit/mutant/parallel/driver_spec.rb

@@ -92,6 +92,14 @@ def apply
         let(:raw_expectations) do
           [
             *super(),
+            {
+              receiver: worker_a,
+              selector: :signal
+            },
+            {
+              receiver: worker_b,
+              selector: :signal
+            },
             {
               receiver: worker_a,
               selector: :join

spec/unit/mutant/parallel/worker_spec.rb

@@ -205,11 +205,6 @@ def apply
 
     let(:raw_expectations) do
       [
-        {
-          receiver:  world.process,
-          selector:  :kill,
-          arguments: ['TERM', pid]
-        },
         {
           receiver:  world.process,
           selector:  :wait,
@@ -223,6 +218,36 @@ def apply
     end
   end
 
+  describe '#signal' do
+    let(:object) do
+      described_class.new(
+        connection: connection,
+        index:      index,
+        pid:        pid,
+        process:    world.process,
+        **shared
+      )
+    end
+
+    def apply
+      object.signal
+    end
+
+    let(:raw_expectations) do
+      [
+        {
+          receiver:  world.process,
+          selector:  :kill,
+          arguments: ['TERM', pid]
+        }
+      ]
+    end
+
+    it 'terminates and waits for process' do
+      verify_events { expect(apply).to be(object) }
+    end
+  end
+
   describe '.start' do
     let(:block)              { ->(value) { value * 2 }                   }
     let(:child_connection)   { instance_double(Mutant::Pipe::Connection) }