### Question:
DomesticTaxCalculator implements TaxCalculator { @Override public double calculate(double amount) { return amount * TAX_PERCENTAGE / 100.0; }  @Override double calculate(double amount); static final double TAX_PERCENTAGE; }### Answer:
@Test public void testTaxCalculation(){ target = new DomesticTaxCalculator(); var tax=target.calculate(100.0); Assertions.assertEquals(tax,20.0); }