PHP Internals Book

The .phpt file structure

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The .phpt file structure

Now that we know how to run the tests with run-tests, let’s dive into a phpt file in more detail. A phpt file is just a normal PHP file but it contains a number of different sections which run-tests supports.

A basic test example

Here’s a basic example of a PHP source test that tests the echo construct.

--TEST--
echo - basic test for echo language construct
--FILE--
<?php
echo 'This works ', 'and takes args!';
?>
--EXPECT--
This works and takes args!

Did you know that echo can take a list of arguments? Well you do now.

There are many more sections that are available to us in a phpt file, but these three are the bare-minimum required. The --EXPECT-- section has a few variations but we’ll get into describing the sections in just a bit.

Notice that of the three sections, we have everything we need to run a black-box test. We have a name for the test, a bit of code and the expected output. Again, black-box testing doesn’t care how the code runs, it only concerns itself with the end result.

Some notable sections

Now that we’ve seen the three required sections for every .phpt file let’s take a look a few other common sections we’ll no doubt encounter.

--TEST-- : The name of the test

The –TEST– section just describes the test (for humans) in one line. This will be displayed in the console when the test is run, so it’s good to be descriptive but not overly verbose. If your test needs a longer description, add a –DESCRIPTION– section.

--TEST--
json_decode() with large integers

Note

The --TEST-- section must be the very first line of the phpt file. Otherwise run-tests will not consider it to be a valid test file and mark the test as “borked”.

--FILE-- : The PHP code to run

The –FILE– section is the PHP code that we want to test. In our above example we’re making sure the echo construct can take a list of arguments and concatenate them into standard out.

--FILE--
<?php
$json = '{"largenum":123456789012345678901234567890}';
$x = json_decode($json);
var_dump($x->largenum);
$x = json_decode($json, false, 512, JSON_BIGINT_AS_STRING);
var_dump($x->largenum);
echo "Done\n";
?>

Note

Although it is considered a best-practice to leave off the closing PHP tag (?>) in userland, this is not the case with a phpt file. If you leave off the closing PHP tag, run-tests will have no trouble running your test, but your test will no longer be able to run as a normal PHP file. It will also make your IDE go bonkers. So always remember to include the closing PHP tag in every --FILE-- section.

--EXPECT-- : The expected output

The –EXPECT– section contains exactly what we would expect to see from standard output. If you’re expecting fancy assertions like you get in PHPUnit, you won’t get any here. Remember, these are `functional tests`_ so we just examine the output after providing inputs.

--EXPECT--
float(1.2345678901235E+29)
string(30) "123456789012345678901234567890"
Done

Note

Trailing new lines are trimmed off by run-tests for both the expected and actual output so you don’t have to worry about adding or removing trailing new lines at the end of the --EXPECT-- section.

--EXPECTF-- : The expected output with substitution

Because the tests need to run on a multitude of environments, we often times may not know what the actual output of a script will be. Or perhaps the functionality that your testing is nondeterministic. For this use case we have the –EXPECTF– section which allows us to substitute sections of output with substitution characters much like the sprintf() function in PHP.

--EXPECTF--
string(%d) "%s"
Done

This is particularly handy when creating error-case tests that output the absolute path to the PHP file; something that would vary from environment to environment.

Below is an abbreviated error-case example taken from a real test of the password hashing functions which makes use of the --EXPECTF-- section.

--TEST--
Test error operation of password_hash() with bcrypt hashing
--FILE--
<?php
var_dump(password_hash("foo", PASSWORD_BCRYPT, array("cost" => 3)));
?>
--EXPECTF--
Warning: password_hash(): Invalid bcrypt cost parameter specified: 3 in %s on line %d
NULL
--SKIPIF-- : Conditions that a test should be skipped

Since PHP can be configured with myriad options, the build of PHP that you’re running might not be compiled with the required dependencies that are needed to run a test. The case where this is most common is the extension tests.

If a test needs an extension installed in order to run the test will have a –SKIPIF– section which checks that the extension is indeed installed.

--SKIPIF--
<?php if (!extension_loaded('json')) die('skip ext/json must be installed'); ?>

Any tests that meet the --SKIPIF-- condition will be marked as “skipped” by run-tests and continue on to the next test in the queue. Any text after the word “skip” will be returned in the output when you run the test from run-tests as the reason why the test was skipped.

Many of the tests will halt the script execution with die() or exit() if the --SKIPIF-- condition is met as in the example above. It is important to understand that just because you die() in a --SKIPIF-- section, that does not mean run-tests will skip your test. Run-tests simply examines the output of --SKIPIF-- and looks for the word “skip” as the first four characters. If the first word is not “skip”, the test will not be skipped.

In fact, you don’t have to halt execution at all as long as “skip” is the first word of the output.

The following example will skip a test. Note how we didn’t halt the script execution.

--SKIPIF--
<?php if (!extension_loaded('json')) echo 'skip'; ?>

By contrast, examine the following example. Notice how it halts script execution but since the word “skip” isn’t the the first word in the output, run-tests will still happily run the test without skipping it.

--SKIPIF--
<?php if (!extension_loaded('json')) exit; ?>

Note

Although it is not required to halt script execution in the --SKIPIF-- section, it is always highly recommended so that you can still run the phpt file as a normal php file and see a nice message like “skip ext/json must be installed” instead of getting a ton of random errors.

--INI--

Sometimes tests rely on having very specific INI settings set. In this case you can define any INI settings with the –INI– section. Each INI setting is place on a new line within the section.

--INI--
date.timezone=America/Chicago

Run-tests does all the magic involved with setting the INI configuration for you.

Writing a simple test

Let’s write our first test just to get familiar with the process.

Typically tests are stored in a tests/ directory that lives near the code we want to test. For example, the PDO extension is found at ext/pdo in the PHP source code. If you open that directory, you’ll see a tests/ directory with lots of .phpt files in it. All the other extensions are set up the same way. There are also tests for the Zend engine which are located in Zend/tests/.

For this example, we’ll just temporarily create a test in the root php-src directory. Create and open a new file with your favorite editor.

$ vi echo_basic.phpt

Note

If you’ve never used vim before, you’ll probably be stuck after running the command above. Just press <esc> a bunch of times and then type :q! and it should poop you back out to the terminal. You can just use your favorite editor for this part instead of vim. And then when you get an extra second later on, learn vim.

Now copy and paste the example test from above into the new test file. Here’s the test file again to save you some scrolling around.

--TEST--
echo - basic test for echo language construct
--FILE--
<?php
echo 'This works ', 'and takes args!';
?>
--EXPECT--
This works and takes args!

After you save the file as echo_basic.phpt in the root of the PHP source code and exit your editor, run the example test with make.

$ make test TESTS=echo_basic.phpt

If everything worked, you’ll see the following passing test summary.

=====================================================================
Running selected tests.
PASS echo - basic test for echo language construct [echo_basic.phpt]
=====================================================================
Number of tests :    1                 1
Tests skipped   :    0 (  0.0%) --------
Tests warned    :    0 (  0.0%) (  0.0%)
Tests failed    :    0 (  0.0%) (  0.0%)
Expected fail   :    0 (  0.0%) (  0.0%)
Tests passed    :    1 (100.0%) (100.0%)
---------------------------------------------------------------------
Time taken      :    0 seconds
=====================================================================

Notice how text from the --TEST-- section of the test is being displayed in the console:

PASS echo - basic test for echo language construct [echo_basic.phpt]

To illustrate the point that black-box testing only cares about the output, let’s change the PHP code in the --FILE-- section and keep everything else the same.

<?php
const BANG = '!';
class works {}
echo sprintf('This %s and takes args%s', works::class, BANG);
?>

Now let’s run the test again.

$ make test TESTS=echo_basic.phpt

The test should still pass because the expected output is still the same as it was before. Let’s try another example. Replace the PHP code in the --FILE-- section of the test with the following code and then run the test again.

<?php
$url = 'https://gist.githubusercontent.com/SammyK/9c7bf6acdc5bcaa2cfbb404adc61abe6/';
$url .= 'raw/04af30473fc78033f7d8941ecd567934b0f804c0/foo-phpt-output.txt';
echo file_get_contents($url);
?>

Although this one looks obscure, I set up a Gist with the expected output and we’re just dumping the body of an HTTP request to that Gist. Unless there are network connection issues or if the gist gets deleted, this will produce the same output as the other bits of code and the test will still pass. This will fail if you don’t have the ext/openssl extension installed since the Gist is behind https.

Let’s try one more example. Replace the PHP code in the --FILE-- section with the following.

<?php
ob_start();

echo 'and ';
sleep(1);
echo 'takes ';
sleep(1);
echo 'args!';

$foo = ob_get_contents();
ob_clean();

echo 'This works ';
sleep(1);
echo $foo;
?>

Crazy, right? This will take a few seconds just to output a simple string and you’d never do this in real life, but the test will still pass. Run-tests does not care that that your code is slow [1] or inefficient or just terrible, if the expected output matches the actual output, your test will be in the green.

[1]Timeouts: The default timeout for run-tests is 60 seconds (or 300 seconds when testing for memory leaks) but you can specify a different timeout using the --set-timeout flag.

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