I need help writing a JUnit test class to test these three classes in java

Employee:

abstract class Employee $\{$

private static int employeeIdStatic $=1$;

private String fName;

private String lName;

private int employeeId;

public Employee$($String fName, String lName$)\{$

this.fName $=$ fName;

this.lName $=$ lName;

this.employeeId $=$ employeeIdStatic;

employeeIdStatic$++$;

$\}$

public String getfName$()\{$

return fName;

$\}$

public String getlName$()\{$

return lName;

$\}$

public int getEmployeeId$()\{$

return employeeId;

$\}$

public void setfName$($String fName$)\{$

this.fName $=$ fName;

$\}$

public void setlName$($String lName$)\{$

this.lName $=$ lName;

$\}$

public String toString$()\{$

return $"$Id:$"+$ employeeId $+"-"+$ fName $+","+$ lName;

$\}$

public abstract double GetPaycheck$()$;

$\}$

SalariedEmployee:

public class SalariedEmployee extends Employee $\{$

protected double salary;

public SalariedEmployee$($String fName, String lName, double salary$)\{$

super$($fName$,$ lName$)$;

this.salary $=$ salary;

$\}$

public double GetPaycheck$()\{$

return salary$/26$;

$\}$

public double getSalary$()\{$

return salary;

$\}$

public void setSalary$($double salary$)\{$

this.salary $=$ salary;

$\}$

@Override

public String toString$()\{$

return String.format$("$Salaried$,$ Base : $$\%,\mathrm{.}2$f; Id:$\%$d $-\%$s$,\%$s$",$ getSalary$(),$ getEmployeeId$(),$ getlName$(),$ getfName$())$;

$\}$

$\}$

HourlyEmployee:

public class HourlyEmployee extends Employee $\{$

private double hourlyRate;

private double hoursWorked;

public HourlyEmployee$($String fName, String lName, double hourlyRate$)\{$

super$($fName$,$ lName$)$;

this.hourlyRate $=$ hourlyRate;

$\}$

public double GetPaycheck$()\{$

return hourlyRate$*$hoursWorked;

$\}$

public double getHourlyRate$()\{$

return hourlyRate;

$\}$

public double getHoursWorked$()\{$

return hoursWorked;

$\}$

public void setHourlyRate$($double hourlyRate$)\{$

this.hourlyRate $=$ hourlyRate;

$\}$

public void setHoursWorked$($double hoursWorked$)\{$

this.hoursWorked $=$ hoursWorked;

$\}$

@Override

public String toString$()\{$

return String.format$("$Hourly: $$\%,\mathrm{.}2$f; Id:$\%$d $-\%$s$,\%$s$",$ hourlyRate, getEmployeeId$(),$ getlName$(),$ getfName$())$;

$\}$

$\}$

CommissionedEmployee:

public class CommissionedEmployee extends SalariedEmployee $\{$

private float$[][]$ commissionSchedule;

private double unitsSold;

public CommissionedEmployee$($String fName, String lName, float$[][]$ commissionSchedule, double salary$)\{$

super$($fName$,$ lName, salary$)$;

this.commissionSchedule $=$ new float$[$commissionSchedule$.$length$][]$;

for $($int i $=0$; i $<$ commissionSchedule.length; i$++)\{$

this.commissionSchedule$[$i$]=$ new float$[$commissionSchedule$[$i$].$length$]$;

for $($int j $=0$; j $<$ commissionSchedule$[$i$].$length; j$++)\{$

this.commissionSchedule$[$i$][$j$]=$ commissionSchedule$[$i$][$j$]$;

$\}$

$\}$

$\}$

public double GetPaycheck$()\{$

float$[][]$ cs $=$ commissionSchedule;

double highestVPU $=0$;

$//$goes through every row

for$($int i $=0$; i $<$ cs$.$length; i$++)\{$

$//$if it meets minimum units sold

if$($unitsSold $>=$ cs$[$i$][0])\{$

if$($cs$[$i$][1]>$ highestVPU$)$

$\{$

highestVPU $=$ cs$[$i$][1]$;

$\}$

$\}$

$\}$

return $(($getSalary$()+$highestVPU$*$unitsSold$)/26)$ ;

$\}$

public double getUnitsSold$()\{$

return unitsSold;

$\}$

public void setUnitsSold$($int unitsSold$)\{$

this.unitsSold $=$ unitsSold;

$\}$

@Override

public String toString$()\{$

return String.format$("$Commission: Base : $$\%,\mathrm{.}2$f; Id:$\%$d $-\%$s$,\%$s$",$ getSalary$(),$ getEmployeeId$(),$ getlName$(),$ getfName$())$;

$\}$

$\}$