Also handle no process ids...

Author: ioquatix

lib/memory/leak/system.rb

@@ -38,9 +38,11 @@ def self.total_memory_size
 			def self.memory_usages(process_ids)
 				return to_enum(__method__, process_ids) unless block_given?
 
-				IO.popen(["ps", "-o", "pid=,rss=", "-p", process_ids.join(",")]) do |io|
-					io.each_line.map(&:split).each do |process_id, size|
-						yield process_id.to_i, size.to_i * 1024
+				if process_ids.any?
+					IO.popen(["ps", "-o", "pid=,rss=", "-p", process_ids.join(",")]) do |io|
+						io.each_line.map(&:split).each do |process_id, size|
+							yield process_id.to_i, size.to_i * 1024
+						end
 					end
 				end
 			end

test/memory/leak/system.rb

@@ -23,6 +23,13 @@
 	end
 
 	with ".memory_usages" do
+		it "can determine the memory usages of no processes" do
+			result = subject.memory_usages([])
+			
+			expect(result).to be_a(Enumerator)
+			expect(result.to_a).to be(:empty?)
+		end
+		
 		it "can determine the memory usages" do
 			pids = 3.times.map{Process.spawn("sleep 1")}