Practical approach for testing your software with php unit

Practical Approach
for testing your
software with PHPUnit
Mario Bittencourt

Agenda
 Current situation
 PHPUnit as part of the solution
 Best Practices

Complexity, dependencies
and pace over time

Software Development
Life Cycle

Testing
 Tedious
 Can only cover a small subset of the use cases
 Takes a lot of time
 Change the code to test it

Automation is key
Goal is to create tests that can be executed
automatically to verify that the expected behaviour
is met

PHPUnit as part
of the solution

Example
class Account
{
protected $balance;
public function __construct($initialAmount)
{
$this->balance = $initialAmount;
}
public function getBalance()
{
return $this->balance;
}
public function deposit($amount)
{
$this->balance += $amount;
}
}

Unit Test
class AccountTest extends PHpUnit_Framework_TestCase
{
public function testDepositIncreasesBalance()
{
$account = new Account(10);
$account->deposit(1);
$this->assertEquals(11, $account->getBalance());
}
}

Unit Test
PHPUnit 4.3.1 by Sebastian Bergmann.
Account
[x] Deposit increases balance

Give meaningful names to your
tests
public function testDeposit()
{
$this->assertEquals(
11,
$account->getBalance()
);
}
 DON’T

tests
Account
[ ] Deposit

tests
public function testDepositIncreaseBalance()
{
11,
$account->getBalance()
);
}

Use the most specific
assertion available
{
$this->assertGreaterThan(
10,$account->getBalance()
);
}
 DON’T

assertion available
{
}

assertion available
{
if ($amount >= 10) {
$this->balance += 1;
}
return true;
}

assertion available
There was 1 failure:
1) AccountTest::testDepositIncreasesBalance
Failed asserting that 21 matches expected 20.
AccountTest.php:14

Don’t forget about protected
methods
class Account
{
{
if ($this->validateAmount($amount)) {
} else {
throw new Exception('Invalid amount');
}
}
}

Don't forget about
your protected methods
protected function validateAmount($amount)
{
if ($amount < 0) {
return false;
} else {
return true;
}
}

Don't forget about
public function testValidateAmountWithNegativeIsFalse()
{
$this->assertFalse($account->validateAmount(-1));
}
Fatal error: Call to protected method Account::validateAmount()

Don't forget about
public function testValidateAmountWithNegativeIsFalse()
{
$reflection = new ReflectionObject($account);
$method = $reflection->getMethod('validateAmount');
$method->setAccessible(true);
$this->assertFalse(
$method->invokeArgs($account, array(-1))
);
}

Don't forget about
Account
[x] Deposit increases balance
[x] Validate amount with negative is false

Test just one thing at a time
{
if ($amount == 0) {
return false;
}
return true;
}

{
$this->assertTrue($account->deposit(1));
$this->assertFalse($account->deposit(0));
}

.
Time: 35 ms, Memory: 3.00Mb
OK (1 test, 3 assertions)

{
if ($amount < 0) {
NEW CRITERIA
return false;
}
return true;
}

There was 1 failure:
1) AccountTest::testDepositIncreasesBalance
Failed asserting that true is false.
AccountTest.php:15
FAILURES!
Tests: 1, Assertions: 3, Failures: 1.

{
$this->assertTrue($account->deposit(1));
}
public function
testDepositWithNegativeShouldReturnFalse()
{
$this->assertFalse($account->deposit(-1));
}

..
OK (2 tests, 3 assertions)

Use Data Providers for
repetitive tests
class Score
{
protected $score;
public function update($balance, $numberCc,
$amountInLoans)
{
// do something ...
return $newScore;
}
}

repetitive tests
class ScoreTest extends PHpUnit_Framework_TestCase
{
public function testScoreSomething1()
{
$score = new Score(10);
$this->assertEquals(300, $score->update(100, 0, 1));
}
public function testScoreSomething2()
{
$this->assertEquals(99, $score->update(100, 1, 2));
}
}

repetitive tests
/**
* @dataProvider scoreProvider
*/
public function testScore($balance, $numberCc,
$amountInLoans, $expectedScore)
{
$expectedScore,
$score->update($balance, $numberCc, $amountInLoans)
);
}

repetitive tests
public function scoreProvider()
{
return array(
array(100, 0, 1, 300),
array(100, 1, 2, 99),
);
}

repetitive tests
..
OK (2 tests, 2 assertions)

Isolate your test
public function wire($amount, SwiftInterface $targetBank)
{
if ($targetBank->transfer($amount)) {
$this->balance -= $amount;
return true;
} else {
return false;
}
}

Isolate your test
class Hsbc implements SwiftInterface {
public function transfer($amount)
{
// slow method
}
}

Isolate your test
public function
testWireTransferShouldReturnTrueIfSuccessful()
{
$bank = new Hsbc();
$this->assertTrue($account->wire(5, $bank));
}

Isolate your test
public function
testWireTransferShouldReturnFalseIfFailed()
{
// how to fail?
$bank = new Hsbc();
$this->assertFalse($account->wire(5, $bank));
}

Isolate your test
public function
testWireTransferShouldReturnTrueIfSuccessful()
{
$bank = $this->getMock(‘Hsbc');
$bank->expects($this->any())
->method('transfer')
->will($this->returnValue(true));
$this->assertTrue($account->wire(5, $bank));
}

Isolate your test
public function
testWireTransferShouldReturnFalseIfFailed()
{
$bank = $this->getMock('Hsbc');
$bank->expects($this->any())
->method('transfer')
->will($this->returnValue(false));
$this->assertFalse($account->wire(5, $bank));
}

Specify what you are testing
with @covers
 Use --coverage-html to generate the code
coverage report of your code

with @covers

with @covers
class Exchange {
public function convert($amountUsd, $targetCurrency)
{
// Do some conversion
}
}

with @covers
public function convertBalance($targetCurrency)
{
$exchange = new Exchange();
return $exchange->convert($this->balance, $targetCurrency);
}

with @covers
public function testConvertBalance()
{
$this->assertLessThan(
10, $account->convertBalance('GBP')
);
}

with @covers
/**
* @covers Account::convertBalance
*/
public function testConvertBalance()
{
…
}

That is all folks!
Contacts
 Twitter -@bicatu
 Email – mbneto@gmail.com
 https://joind.in/12279
 http://slidesha.re/1xtcT4y

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