1. <?php
2.  
3. class Calculator
4. {
5.  public static function add($a, $b)
6.  {
7.   return $a + $b;
8.  }
9.  
10.  public static function divide($a, $b)
11.  {
12.   return $a / $b;
13.  }
14. }
15.  
16. use PHPUnit\Framework\TestCase;
17.  
18. class CalculatorTest extends TestCase
19. {
20.     public function testAddition(): void
21.     {
22.         // Positive Test Case 1: add() method
23.         $a = 5;
24.         $b = 10;
25.         $expectedSum = 15;
26.         $sum = Calculator::add($a, $b);
27.         $this->assertEquals($expectedSum, $sum);
28.     }
29.  
30.     public function testDivision(): void
31.     {
32.         // Positive Test Case 2: divide() method
33.         $a = 20;
34.         $b = 4;
35.         $expectedQuotient = 5;
36.         $quotient = Calculator::divide($a, $b);
37.         $this->assertEquals($expectedQuotient, $quotient);
38.     }
39.  
40.     public function testAdditionWithInvalidInput(): void
41.     {
42.         // Negative Test Case 1: add() method with invalid input
43.         $a = "abc";
44.         $b = 10;
45.         $this->expectException(TypeError::class);
46.         Calculator::add($a, $b);
47.     }
48.  
49.     public function testDivisionByZero(): void
50.     {
51.         // Negative Test Case 2: divide() method with division by zero
52.         $a = 10;
53.         $b = 0;
54.         $this->expectException(DivisionByZeroError::class);
55.         Calculator::divide($a, $b);
56.     }
57. }
58.