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

CommandValuesDescription
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 -https://staging2.appodeal.com:443)Command 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