Wepresentanewtestingsemantics,calledfriendlytesting,whosemainpropertyisthattheinducedpreorderbetweenprocessesContaininfrisconsistentwiththeconformancerelation,andsowehave,forinstance,a+bContaininfraContaininfra+b.ThenewtheoryisstronglybasedonDeNicola&Hennessy'sworkontesting.Friendlytestsaredefinedexactlyasintheirwork,exceptthatinternalactionsarenotallowed.However,inordertoobtainthedesirednotionoffriendlytestingthisrestrictionisnotenoughandwealsohavetorelaxtheconditionstopassatest.ThusweobtainanewtestingsemanticsandanewpreorderbetweenprocesseswhichisstrictlyweakerthantherelationContaininmust.Moreover,wepresentanaltrnativecharacterizationofournewtestingsemanticsbydefiningamodificationofacceptancesets.
