calculateFamilyTuition([ ['student_id' => 4, 'student_name' => 'Fourth', 'grade_level' => '4'], ['student_id' => 1, 'student_name' => 'First', 'grade_level' => '1'], ['student_id' => 3, 'student_name' => 'Third', 'grade_level' => '3'], ['student_id' => 2, 'student_name' => 'Second', 'grade_level' => '2'], ], [ 'grade_fee' => 9, 'new_tuition_full_amount' => '350.00', 'new_tuition_second_student_discount' => '50.00', 'new_tuition_third_student_discount' => '50.00', 'new_tuition_fourth_plus_discount' => '100.00', ]); $this->assertSame('1200.00', $result['total']); $this->assertSame('350.00', $result['details'][0]['amount']); $this->assertSame('300.00', $result['details'][1]['amount']); $this->assertSame('300.00', $result['details'][2]['amount']); $this->assertSame('250.00', $result['details'][3]['amount']); } public function testDiscountCannotDriveAmountBelowZero(): void { $service = new NewTuitionCalculatorService(); $result = $service->calculateFamilyTuition([ ['student_id' => 1, 'student_name' => 'One', 'grade_level' => '1'], ['student_id' => 2, 'student_name' => 'Two', 'grade_level' => '2'], ['student_id' => 3, 'student_name' => 'Three', 'grade_level' => '3'], ['student_id' => 4, 'student_name' => 'Four', 'grade_level' => '4'], ['student_id' => 5, 'student_name' => 'Five', 'grade_level' => '5'], ], [ 'grade_fee' => 9, 'new_tuition_full_amount' => '75.00', 'new_tuition_second_student_discount' => '50.00', 'new_tuition_third_student_discount' => '50.00', 'new_tuition_fourth_plus_discount' => '100.00', ]); $this->assertSame('125.00', $result['total']); $this->assertSame('0.00', $result['details'][3]['amount']); $this->assertSame('0.00', $result['details'][4]['amount']); } }