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phpunit-testingexceptionphpunit
ConorSheehan1
ConorSheehan1

Reputation: 1725

PHPUnit expect exception failing due to foreach warning

I want to test that a method called foo() throws an exception. The problem is that I can't get PHPUnit expectException() to catch the exception.

foo() looks something like this:

public function foo()
{
    $params = $this->readAndFormatConfig();
    // exception actually gets thrown in this method
    $this->method->throws->exception($params);
}

If I catch the exception manually it works fine, like this:

public function testFoo()
{
    $badConfig = new Config([]);
    $driver = new bar($badConfig);

    $exceptionThrown = false;
    try {
        $driver->foo();
    } catch (Exception $e) {
        $exceptionThrown = true;
    }
    $this->assertTrue($exceptionThrown);
}

If I catch it using expectException, like this:

public function testFoo()
{
    $badConfig = new Config([]);
    $driver = new bar($badConfig);
    $this->expectException(Exception::class);
    $driver->foo();
}

the test fails and I get this exception:

MyTestClass::testFoo Invalid argument supplied for foreach()

The output of get_class($e) is PHPUnit_Framework_Error_Warning which surprised me, but explains why the first test works but the second doesn't.

I'd like to either ignore the warning and wait until a real exception is thrown, or get the original warning, not PHPUnit_Framework_Error_Warning.

I'm using php 5.6.32 and PHPUnit 5.7.15

Upvotes: 1

Views: 655

Answers (1)

ConorSheehan1
ConorSheehan1

Reputation: 1725

Adding the following to boostrap.php converts warnings to exceptions.

function warningToException($errno, $errstr, $errfile, $errline)
{
    throw new Exception($errstr . " on line " . $errline . " in file " . $errfile);
}

set_error_handler("warningToException", E_WARNING);

This allowed the following test pass.

public function testFoo()
{
    $badConfig = new Config([]);
    $driver = new bar($badConfig);
    $this->expectException(Exception::class);
    $driver->foo();
}

I think a better method would be to expect PHPUnit_Framework_Error_Warning in the test as ishegg suggested.

What I ended up actually doing was making sure the object I was passing to foreach was traversable before entering the loop. 

public function foo()
{
    if (is_array($x) || $x instanceof \Traversable) {
        // do stuff
    } else {
        // return false;
    }
}

I think it makes more sense to refactor the application code in this case. What I'm really trying to test is that the function foo returns false if the application is misconfigured, so handling the misconfiguration properly seems like the right path in my opinion.

If you stumble upon this question for some reason and really need to convert warnings to an exception class other than PHPUnit_Framework_Error_Warning this is how I did it.

Thanks to ishegg for pointing me in the right direction.

Upvotes: 1

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