# Execute the test case.
	fun run do
		toolcontext.info("Execute test-case {test_method.name}", 1)
		was_exec = true
		if toolcontext.opt_noact.value then return
		# execute
		var method_name = test_method.name
		var test_file = test_suite.test_file
		var res_name = "{test_file}_{method_name.escape_to_c}"
		var clock = new Clock
		var res = toolcontext.safe_exec("{test_file}.bin {method_name} > '{res_name}.out1' 2>&1 </dev/null")
		if not toolcontext.opt_no_time.value then real_time = clock.total

		var raw_output = "{res_name}.out1".to_path.read_all
		self.raw_output = raw_output
		# set test case result
		if res != 0 then
			error = "Runtime Error in file {test_file}.nit"
			toolcontext.modelbuilder.failed_tests += 1
		else
			# no error, check with res file, if any.
			var mmodule = test_method.mclassdef.mmodule
			var file = mmodule.filepath
			if file != null then
				var tries = [ file.dirname / mmodule.name + ".sav" / test_method.name + ".res",
					file.dirname / "sav" / test_method.name + ".res" ,
					file.dirname / test_method.name + ".res" ]
				var savs = [ for t in tries do if t.file_exists then t ]
				if savs.length == 1 then
					var sav = savs.first
					toolcontext.info("Diff output with {sav}", 1)
					res = toolcontext.safe_exec("diff -u --label 'expected:{sav}' --label 'got:{res_name}.out1' '{sav}' '{res_name}.out1' > '{res_name}.diff' 2>&1 </dev/null")
					if res == 0 then
						# OK
					else if toolcontext.opt_autosav.value then
						raw_output.write_to_file(sav)
						info = "Expected output updated: {sav} (--autoupdate)"
					else
						self.raw_output = "Diff\n" + "{res_name}.diff".to_path.read_all
						error = "Difference with expected output: diff -u {sav} {res_name}.out1"
						toolcontext.modelbuilder.failed_tests += 1
					end
				else if savs.length > 1 then
					toolcontext.info("Conflicting diffs: {savs.join(", ")}", 1)
					error = "Conflicting expected output: {savs.join(", ", " and ")} all exist"
					toolcontext.modelbuilder.failed_tests += 1
				else if not raw_output.is_empty then
					toolcontext.info("No diff: {tries.join(", ", " or ")} not found", 1)
					if toolcontext.opt_autosav.value then
						var sav = tries.first
						sav.dirname.mkdir
						raw_output.write_to_file(sav)
						info = "Expected output saved: {sav} (--autoupdate)"
					end
				end
			end
		end
		is_done = true
	end