Overview of SimpleTest

What is SimpleTest?

The heart of SimpleTest is a testing framework built around test case classes. These are written as extensions of base test case classes, each extended with methods that actually contain test code. Top level test scripts then invoke the run() methods on every one of these test cases in order. Each test method is written to invoke various assertions that the developer expects to be true such as assertEqual(). If the expectation is correct, then a successful result is dispatched to the observing test reporter, but any failure triggers an alert and a description of the mismatch.

A test case looks like this...


class MyTestCase extends UnitTestCase {
    function testCreatedLogFile() {
        $log = &new Log('my.log');

These tools are designed for the developer. Tests are written in the PHP language itself more or less as the application itself is built. The advantage of using PHP itself as the testing language is that there are no new languages to learn, testing can start straight away, and the developer can test any part of the code. Basically, all parts that can be accessed by the application code can also be accessed by the test code, if they are in the same programming language.

The simplest type of test case is the UnitTestCase. This class of test case includes standard tests for equality, references and pattern matching. All these test the typical expectations of what you would expect the result of a function or method to be. This is by far the most common type of test in the daily routine of development, making up about 95% of test cases.

The top level task of a web application though is not to produce correct output from its methods and objects, but to generate web pages. The WebTestCase class tests web pages. It simulates a web browser requesting a page, complete with cookies, proxies, secure connections, authentication, forms, frames and most navigation elements. With this type of test case, the developer can assert that information is present in the page and that forms and sessions are handled correctly.

A WebTestCase looks like this...


class MySiteTest extends WebTestCase {
    function testHomePage() {
        $this->assertTitle('My Home Page');
        $this->assertTitle('Contact me');
        $this->assertPattern('/Email me at/');

Feature list

The following is a very rough outline of past and future features and their expected point of release. I am afraid it is liable to change without warning, as meeting the milestones rather depends on time available. Green stuff has been coded, but not necessarily released yet. If you have a pressing need for a green but unreleased feature then you should check-out the code from Sourceforge SVN directly.

Unit test case Core test case class and assertions 1.0
Html display Simplest possible display 1.0
Autoloading of test cases Reading a file with test cases and loading them into a group test automatically 1.0
Mock objects Objects capable of simulating other objects removing test dependencies 1.0
Web test case Allows link following and title tag matching 1.0
Partial mocks Mocking parts of a class for testing less than a class or for complex simulations 1.0
Web cookie handling Correct handling of cookies when fetching pages 1.0
Following redirects Page fetching automatically follows 300 redirects 1.0
Form parsing Ability to submit simple forms and read default form values 1.0
Command line interface Test display without the need of a web browser 1.0
Exposure of expectation classes Can create precise tests with mocks as well as test cases 1.0
XML output and parsing Allows multi host testing and the integration of acceptance testing extensions 1.0
Browser component Exposure of lower level web browser interface for more detailed test cases 1.0
HTTP authentication Fetching protected web pages with basic authentication only 1.0
SSL support Can connect to https: pages 1.0
Proxy support Can connect via. common proxies 1.0
Frames support Handling of frames in web test cases 1.0
File upload testing Can simulate the input type file tag 1.0.1
Mocking interfaces Can generate mock objects to interfaces as well as classes and class interfaces are carried for type hints 1.0.1
Testing exceptions Similar to testing PHP errors 1.0.1
HTML label support Can access all controls using the visual label 1.0.1
Base tag support Respects page base tag when clicking 1.0.1
PHP 5 E_STRICT compliant PHP 5 only version that works with the E_STRICT error level 1.1
BDD style fixtures Can import fixtures using a mixin like given() method 1.5
Reporting machinery enhancements Improved message passing for better cooperation with IDEs 1.5
Fluent mock interface More flexible and concise mock objects 1.6
Localisation Messages abstracted and code generated 1.6
CSS selectors HTML content can be examined using CSS selectors 1.7
HTML table assertions Can match HTML or table elements to expectations 1.7
Unified acceptance testing model Content searchable through selectors combined with expectations 1.7
DatabaseTestCase SQL selectors and DB drivers 1.7
IFrame support Reads IFrame content that can be refreshed 1.8
Alternate HTML parsers Can detect compiled parsers for performance improvements 1.8
Integrated Selenium support Easy to use built in Selenium driver and tutorial 1.9
Code coverage Reports using the bundled tool when using XDebug 1.9
Deprecation of old methods Simpler interface for SimpleTest2 2.0
Javascript suport Use of PECL module to add Javascript to the native browser 3.0
PHP5 migraton will start straight after the version 1.0.1 series, whereupon only PHP 5.1+ will be supported. SimpleTest is currently compatible with PHP 5, but will not make use of all of the new features until version 1.1.

Web resources for testing

Process is at least as important as tools. The type of process that makes the heaviest use of a developer's testing tool is of course Extreme Programming. This is one of the Agile Methodologies which combine various practices to "flatten the cost curve" of software development. More extreme still is Test Driven Development, where you very strictly adhere to the rule of no coding until you have a test. If you're more of a planner, or believe that experience trumps evolution, you may prefer the RUP approach. I haven't tried it, but even I can see that you will need test tools (see figure 9).

Most unit testers clone JUnit to some degree, as far as the interface at least. There is a wealth of information on the JUnit site including the FAQ which contains plenty of general advice on testing. Once you get bitten by the bug you will certainly appreciate the phrase test infected coined by Eric Gamma. If you are still reviewing which unit tester to use you can find pretty complete lists from Wikipedia, Software testing FAQ, and Open source testing.

There is still very little material on using mock objects, which is a shame as unit testing without them is a lot more work. The original mock objects paper is very Java focused, but still worth a read. The most authoritive sources are probably the original mock objects site and JMock. Java centric, but tucked away in PDFs they contain some deep knowledge on using mocks from the extended experience of the concept inventors. As a new technology there are plenty of discussions and debate on how to use mocks, often on Wikis such as Extreme Tuesday or www.mockobjects.com or the original C2 Wiki. Injecting mocks into a class is the main area of debate for which this paper on IBM makes a good starting point.

There are plenty of web testing tools, but the scriptable ones are mostly are written in Java and tutorials and advice are rather thin on the ground. The only hope is to look at the documentation for HTTPUnit, HTMLUnit or JWebUnit and hope for clues. There are some XML driven test frameworks, but again most require Java to run.

Most significant is a new generation of tools that run directly in the web browser are now available. These include Selenium and Watir. They are non-trivial to set up and slow to run, but can essentially test anything. As SimpleTest does not support JavaScript you would probably have to look at these tools anyway if you have highly dynamic pages.

Quick summary of the SimpleTest tool for PHP.
List of features, both current ones and those planned.
There are plenty of unit testing resources on the web.
Documentation for SimpleTest.
How to write PHP test cases is a fairly advanced tutorial.
SimpleTest API from phpdoc.