As long it is a brushed motor which is the type that only has two wires then it can be tested by wiring it straight to the battery pack.
Speed controllers are too complex to easily test so testing the other components that are connected to the speed controller and using the process of elimination is the best method to determine if the speed controller is working or not. If all of the other parts that are connected to the speed controller test good then the speed controller has to be the problem.
Here is a link to our guide on troubleshooting the speed controller to determine if it is good or bad: https://electricscooterparts.com/troubleshootingspeedcontrollerdoesnotwork.html
Bob Brooks
4 people have this question