php代码测试功能的代码覆盖率分析与优化策略

<?php
class Calculator {
  
  public function add($a, $b) {
    return $a + $b;
  }
  
  public function subtract($a, $b) {
    return $a - $b;
  }
  
  public function multiply($a, $b) {
    return $a * $b;
  }
  
  public function divide($a, $b) {
    if ($b == 0) {
      throw new Exception('Division by zero');
    }
    return $a / $b;
  }
  
}

<?php
require_once 'Calculator.php';

use PHPUnitFrameworkTestCase;

class CalculatorTest extends TestCase {
  
  public function testAdd() {
    $calculator = new Calculator();
    $result = $calculator->add(2, 3);
    $this->assertEquals(5, $result);
  }
  
  public function testSubtract() {
    $calculator = new Calculator();
    $result = $calculator->subtract(5, 3);
    $this->assertEquals(2, $result);
  }
  
  public function testMultiply() {
    $calculator = new Calculator();
    $result = $calculator->multiply(2, 3);
    $this->assertEquals(6, $result);
  }
  
  public function testDivide() {
    $calculator = new Calculator();
    $result = $calculator->divide(6, 3);
    $this->assertEquals(2, $result);
  }
  
}