Master PHP Unit Testing with PHPUnit: Essential Guide & Best Practices
Unlock the power of PHPUnit in PHP development with our comprehensive guide on unit testing and best practice...
Write PHPUnit tests
Certainly! Below are examples of PHPUnit tests for a simple class that performs basic arithmetic operations. The class we will be testing is called Calculator, and it has methods for addition, subtraction, multiplication, and division.
### Calculator Class
Here's the implementation of the Calculator class:
php
calculator = new Calculator();
}
public function testAdd()
{
$this->assertEquals(5, $this->calculator->add(2, 3));
$this->assertEquals(0, $this->calculator->add(-2, 2));
$this->assertEquals(-1, $this->calculator->add(-2, 1));
}
public function testSubtract()
{
$this->assertEquals(-1, $this->calculator->subtract(2, 3));
$this->assertEquals(-4, $this->calculator->subtract(-2, 2));
$this->assertEquals(-1, $this->calculator->subtract(-2, -1));
}
public function testMultiply()
{
$this->assertEquals(6, $this->calculator->multiply(2, 3));
$this->assertEquals(0, $this->calculator->multiply(0, 2));
$this->assertEquals(-4, $this->calculator->multiply(-2, 2));
}
public function testDivide()
{
$this->assertEquals(2, $this->calculator->divide(6, 3));
$this->assertEquals(-1, $this->calculator->divide(-4, 4));
$this->assertEquals(0, $this->calculator->divide(0, 1));
}
public function testDivideByZero()
{
$this->expectException(InvalidArgumentException::class);
$this->calculator->divide(1, 0);
}
}
### Explanation of the Tests:
1. **testAdd()**: Verifies that the addition method returns the correct sum for various cases, including positive, negative, and zero.
2. **testSubtract()**: Checks if the subtraction method correctly calculates differences, including scenarios with negative inputs.
3. **testMultiply()**: Tests the multiplication method with positive, negative, and zero values to ensure it behaves correctly.
4. **testDivide()**: Ensures that division returns the expected results for various inputs, including dividing by zero.
5. **testDivideByZero()**: Confirms that attempting to divide by zero throws an InvalidArgumentException, as expected.
### Running the Tests
To run these tests, save the Calculator class in a file called Calculator.php and the test class in a file named CalculatorTest.php. Make sure you have PHPUnit installed and then run the following command in the terminal:
bash
phpunit CalculatorTest.php
If everything is set up correctly and the tests pass, you should see an output indicating that all tests were successful.