FishOfPreySettingsMockProvider.java

public class FishOfPreySettingsMockProvider implements System.StubProvider {
	
	private FishOfPrey_Settings__c testingSettings;

    public Object handleMethodCall(Object stubbedObject, String stubbedMethodName, 
        	Type returnType, List<Type> listOfParamTypes, List<String> listOfParamNames, 
        	List<Object> listOfArgs) {
			
		string methodName = 'FishOfPreySettingsMockProvider.handleMethodCall() - ';
               
        // You can use the method name and return type to determine which method was called.
        System.debug(LoggingLevel.Debug, methodName + 'Name of stubbed method: ' + stubbedMethodName +
					'\nReturn type of stubbed method: ' + returnType.getName() + 
					'\n number of parameters passed into the mocked call: ' + listOfArgs.size() + 
					'\n parameter(s) sent into the mocked call: ' + listOfArgs);
        
        if(stubbedMethodName == 'getFishOfPreyCustomSettings') {
			if(testingSettings == null) {
				testingSettings = new FishOfPrey_Settings__c();
			}
			return testingSettings;
		} else if (stubbedMethodName == 'setFishOfPreyCustomSettings') {
			System.debug(methodName + ' ignoring call to ' + stubbedMethodName);
			return null;
		} else if (stubbedMethodName == 'upsertSettingsChange') {
			System.debug(methodName + ' ignoring call to ' + stubbedMethodName);
			return null;
		}
		
		System.assert(false, methodName + 'unmocked stubbedMethodName: ' + stubbedMethodName);
		
        return null;
    }
}