quit trying to stream IO streams that have closed

lib/background_process/io_helpers.rb

@@ -4,17 +4,18 @@ def detect(streams = [], timeout = nil, &block)
     begin
       Timeout::timeout(timeout) do
         # Something that should be interrupted if it takes too much time...
-        while true
-          available_streams, _, _ = Kernel.select(streams, nil, nil, 1)
-          available_streams.each do |s|
+        until streams.empty?
+          active_streams, _, _ = Kernel.select(streams, nil, nil, 1)
+          active_streams.each do |s|
+            (streams -= [s]; next) if s.eof?
             content = s.gets
             if result = (block.arity == 1 ? yield(content) : yield(s, content))
               return result
             end
-          end if available_streams
+          end if active_streams
         end
       end
-      true
+      nil
     rescue Timeout::Error
       nil
     end

spec/background_process/background_process_spec.rb

@@ -110,5 +110,20 @@
         raise(Spec::Expectations::ExpectationNotMetError, "expected to not yield the block")
       end
     end
+
+    it "quits when the process does" do
+      process = BackgroundProcess.run("sleep 0.3")
+      started_waiting = Time.now
+      result = process.detect(:both, 1) do |line|
+        line.should_not be_nil
+      end
+      result.should be_nil
+      (Time.now - started_waiting).should < 0.4
+    end
+
+    it "yields the very last bit of the process output" do
+      process = BackgroundProcess.run("echo hello; printf hi")
+      process.detect(:both, 1) { |line| line == "hi" }.should == true
+    end
   end
 end