I need help passing boolean to main from another class

The problem I am having is I want to input the parameters to the Compounding class that then gives me a result and then by using a boolean check in the main tell me if each parameter is correct. Basically a form of testing that my professor is having us do in class. My problem is I cant get a boolean to pass to the main because of my double variables. I am kinda stuck on what to do and cannot figure out how to fix this.

package compoundInterest; package compoundInterest;

public class Main {

public static void main(String[] args) {
    CompInterest Debt = new CompInterest();
    System.out.println("lets see if this works");
    System.out.printf("$%.2f",Debt.TotalCompInterest(10,10_000,3.5));

}
public boolean testYear() {
    CompInterest T = new CompInterest();
    boolean Test = T.TotalCompInterest(10, 10_000, 3.5);
    System.out.println("results of test #1 = " + Test );

    if(Test == true){
    System.out.println("The test passed!");
    } else {
    System.out.println("The test failed!");
   }
}

} public class CompInterest {

public boolean TotalCompInterest
(double year, double principle, double rate) {

double amount = 0;
double timesComp = 1;

rate=(1+rate/100);

for(int i=0;i<year;i++)
timesComp*=rate;
amount=principle*timesComp;

double CompInt = amount-principle;
return true;
}

}