Starting from SDK 2.8.0 we've added new logic to enable test mode via ADB commands, which can be used with Debug and Release builds of apps

adb shell setprop debug.appodeal.sdk.testmodetrue / false / .none.Command for set Test Mode 
adb shell setprop debug.appodeal.sdk.logtrue / false / .none.Command for enabling/disabling logs
adb shell setprop debug.appodeal.sdk.loglevelnone / debug / verbose / .none.Command for set logging level
adb shell setprop debug.appodeal.sdk.urlString in a proper format (e.g - for set Appodeal SDK request url
adb shell setprop debug.appodeal.sdk.testactivitytrue / false / .none.Command for enabling Test Activity starting on SDK initialization
adb shell setprop debug.appodeal.sdk.networksAn array of strings, with comma divider (e.g - admob,unity_ads,...)Command for set enabled ad networks

.none. - is the default state for all commands and related parameters