Linux specific tests.

Author: samuel-williams-shopify

test/process/general.rb

@@ -4,6 +4,8 @@
 # Copyright, 2024-2025, by Samuel Williams.
 
 require "process/metrics"
+# On Linux, load ps backend too so we can compare General (Linux) vs General::ProcessStatus in tests.
+require "process/metrics/general/process_status" if RUBY_PLATFORM.include?("linux")
 
 describe Process::Metrics::General do
 	with ".capture" do
@@ -100,4 +102,56 @@ def after(error = nil)
 			expect(child.process_group_id).to be_a(Integer)
 		end
 	end
+
+	with "Linux backend matches ps backend (Linux only)" do
+		it "single pid capture matches" do
+			skip "Linux with ps required" unless RUBY_PLATFORM.include?("linux") && Process::Metrics::General::ProcessStatus.supported?
+
+			pid = Process.pid
+			linux = Process::Metrics::General.capture(pid: pid, memory: false)
+			ps = Process::Metrics::General::ProcessStatus.capture(pid: pid, memory: false)
+
+			expect(linux.keys).to be == ps.keys
+			linux.each_key do |p|
+				l = linux[p]
+				ps_process = ps[p]
+				expect(ps_process).not.to be_nil
+				expect(l.process_id).to be == ps_process.process_id
+				expect(l.parent_process_id).to be == ps_process.parent_process_id
+				expect(l.process_group_id).to be == ps_process.process_group_id
+				expect(l.virtual_size).to be == ps_process.virtual_size
+				expect(l.resident_size).to be == ps_process.resident_size
+				expect(l.command).to be == ps_process.command
+				expect((l.processor_time - ps_process.processor_time).abs).to be < 1.0
+				expect((l.elapsed_time - ps_process.elapsed_time).abs).to be < 1.0
+			end
+		end
+
+		it "pid and ppid capture matches" do
+			skip "Linux with ps required" unless RUBY_PLATFORM.include?("linux") && Process::Metrics::General::ProcessStatus.supported?
+
+			child_pid = Process.spawn("sleep 10")
+			begin
+				linux = Process::Metrics::General.capture(pid: child_pid, ppid: child_pid, memory: false)
+				ps = Process::Metrics::General::ProcessStatus.capture(pid: child_pid, ppid: child_pid, memory: false)
+				expect(linux.keys.sort).to be == ps.keys.sort
+				linux.each_key do |p|
+					l = linux[p]
+					ps_process = ps[p]
+					expect(ps_process).not.to be_nil
+					expect(l.process_id).to be == ps_process.process_id
+					expect(l.parent_process_id).to be == ps_process.parent_process_id
+					expect(l.process_group_id).to be == ps_process.process_group_id
+					expect(l.virtual_size).to be == ps_process.virtual_size
+					expect(l.resident_size).to be == ps_process.resident_size
+					expect(l.command).to be == ps_process.command
+					expect((l.processor_time - ps_process.processor_time).abs).to be < 1.0
+					expect((l.elapsed_time - ps_process.elapsed_time).abs).to be < 1.0
+				end
+			ensure
+				Process.kill(:TERM, child_pid)
+				Process.wait(child_pid)
+			end
+		end
+	end
 end