Everything is possible with PHP

Php can really do anything. Essentially, its application field is focused on writing of scripts, which work on server side. So Php is able to perform all that performs any other CGI program, for instance, to process form data, generate dynamic pages or send and accept cookies. But PHP can fulfill many more tasks.

There are 3 main fields, where Php is used:

• Scripts creating for implementing on server side. Php is used most widely exactly this way. All what you'll need are Php parser (in the form of CGI program or server module), web-server and browser. For you to track the results of Php scripts implementation in browser you need a working web-server and installed Php case you just experiment, you can use your home computer instead of server;
• Script creation for implementation in a command line. You can create a Php script, which is able to launch independently from web-server and browser. All that you will need is a Php parser. Yjis way of Php using suits perfectly for scripts, which should be executed regularly, for example, by means of cron (on Unix or Linux platforms) or Task Scheduler on Windows platforms. These scripts can also be used for simple text processing tasks;
• Creation of windows applications, which are executed on a client's side. Maybe Php isn't the best language for creation of such applications, but if you know Php very well and want to use some of its facilities for your client-applications, then you can use PHP-GTK to create such applications. In such a way you can create cross-platform applications. PHP-GTK is Php extension and isn't supplied together with Php distribution disk;

Php is available for the majority of operational systems, including Linux, many Unix modifications (such as HP-UX, Solaris and OpenBSD), Microsoft Windows, Mac OS X, RISC OS, and many others. In php is also included support of the majority of modern web-servers, such as Apache, Microsoft Internet Information Server, Personal Web Server, Netscape and iPlane servers, Oreilly Website Pro, Caudium, Xitami, OmniHTTPd servers and many others. For the majority of servers Php is supplied as a module, for others, which support CGI standard, Php can function as a CGI processor.

So, when choosing Php you get the freedom of choice of an operational system and a web-server. Besides, you get the choice either to use procedure-oriented programming or object-oriented programming or even their combination.

Php is able not only to deliver HTML. Php facilities include images, PDF files or even Flash reels formation, which can be created "on the fly". Php can also deliver any text data, such as XHTML and other XML-files. Php is able to perform automatic generation of such files and save them in file system of your server instead of giving to a client, in such a way organizing dynamic content cash located on a server side.

One of the most considerable Php advantages is a support of a wide data bases range. It is very simple to create a script, which uses data bases.
Today Php supports the following: Adabas D, InterBase, PostgreSQL, dBase, FrontBase, SQLite, Empress mSQL, Solid, Direct MS-SQL, Sybase, Hyperwave, MySQL, Velocis, IBM DB2 ODBC, Unix dbm Informix, Oracle (OCI7 и OCI8), Ingres, Ovrimos.

There is also DBX support for work at the abstract level in Php, so that you can work with any data base that uses Php. Besides, php supports ODBC (Open Database Connection standard), so that you can work with any DB supporting that recognized world-wide standard. Php also supports "communication" with other services using such protocols as LDAP, IMAP, SNMP, NNTP, POP3, HTTP, COM (on Windows platform) and many others. Besides, you get an opportunity to work with network sockets directly. Php supports the standard of exchange of complex data structures WDDX. We can't but mention here Java objects support and the possibility of their usage as Php objects. To access remote objects you can use CORBA extension.

Of paramount importance is electronic commerce and payment realization functions - Cybercash, CyberMUT, VeriSign Payflow Pro and CCVS. And the last but not the least we should mention support of many other extensions, such as mnoGoSearch machine functions, IRC Gateway functions, functions for work with compressed files (gzip, bz2), functions of calendar calculations, translation and much more.

Software methodology and testing practice.

It hardly makes sense to tell you about the significance of testing period in the context of software development process, it has been a well-known fact for a long time that implementation of each application life cycle stage is an indispensable condition for high-quality software product emergence. But here we need to admit that through the history of software testing - it counts more than 50 years - testing has played the role of a step child, who is in charge of the most complicated, routine and second-rate work. Here is a bright example: author's rights are secured by law, you can easily know them. But what do we know about those people who test applications, and yet their share of software development is almost the third of the whole work process.

Recently the situation has changed greatly, and one can single out here 2 main tendencies. The first one - there grows understanding of the fact, that industrial test methods should be applied, special automation means in particular. The second - search for expenditure optimization facilities from the point of view of general business organization, including usage of outsourcing model.

It is worth mentioning the fact that there is plenty of literature and courses on software designing and coding, meanwhile materials on testing and adjustment are practically lacking.

Peculiarities of testing organization.

Firstly, one needs to mention, that testing issues are to be considered in the context of the whole software life cycle, beginning from technical specification and ending with application maintenance. As we know, testing stage - is a procedure of software error detection before its industrial application. It is obvious, that work content here is connected with the number of errors, in connection with that one should clearly define basic causes of their appearance:

• insufficient organizational, methodical and technical support of the development process;
• undertime of project implementation;
• project complexity, great number of requirements and their alterations as the work advances;
• insufficient developers' experience.

Testing in its turn is only a component of adjustment – software fine-tuning process before its startup. This process includes 2 basic procedures: error detection (testing) and search for their causes and their elimination. However, taking into consideration all possible interconnections of those procedures (for example, error detection requires carrying out additional testing), one should emphasize, that testing is quite a stand-alone, independent software life cycle stage. Meanwhile, rise of development quality brings directly down expenditures on errors elimination, but it doesn’t affect so much scope of testing: testing must be carried out in any case and it is desirable to do it at full scale.

It is also obvious that testing organization and procedure depend greatly on target development purpose: commercial off-the-shelf software, custom project or in-house project. Speaking about testing peculiarities in IT departments it is necessary to single out 3 main contradictory aspects. Testing volume is big. The thing is that exactly in case of in-house development they very often make changes (many people mention continuous flow of corrections on demands of department-customers). But as is generally known, the principle says that a change in one code line demands repeated carrying out of complete testing process.

Very often developers are not interested in decreasing the number of bugs while testing. Companies' management estimates the work of IT department according to its ability to keep within the budget (time and money), and programs' operation problems bother them considerably less. That's why growth of testing volume increases IT department expenditures without corresponding resources allocation from authorities.

The process of quality testing demands specialists and corresponding profile tools availability. And as we have described before, it is not advantageous for IT departments to keep in-house testers.

Common testing questions.

Increase of software testing quality (preserving reasonable level of expenditures on its implementation) should be performed by means of modern industrial methods (organizational and technical) for the implementation of those operations.

The article's limits do not allow expounding application issues of concrete tools in details. It will be more useful to consider some general questions concerning testing tasks classification. Testing runs through the entire software life cycle, beginning from designing and ending with indefinitely long operation period. These operations are directly connected with tasks of requirements and alterations' management, as the goal of testing is exactly the possibility to make sure that programs correspond to the announced requirements.

Testing is a step-by-step process. Probably, it makes sense to divide check process of operability in the course of code writing (by programmer himself) and after completion of the principal coding stage (by special testers). Here you can remember the golden rule of programming: writing of every 20-30 lines of code (all the more so completed procedures, functions) should be accompanied by check of their operability. At the same time, it is important to stress the significant difference between testing in the course of coding process and after its termination: in the first case one should continue program writing (launching other test examples) only after elimination of an error, in the second case an instruction burst of a test series with a simple results fixation is implemented.

Testing is also an iterative process. After each bug is found and fixed, it is obligatory to carry out test replication in order to make sure of program workability. Moreover, to identify the reason of a problem that has been found, there should be carried out an additional testing. Meanwhile, one should remember the fundamental conclusion made by professor Edceger Dakestroy in 1972: "Program testing can be a proof of errors presence, but it will never prove their absence!".

Different kinds of testing may be classified according to following basic characteristics (though any categorization is quite relative).

Functional and charging testing.

Operations of the first type one can label as traditional - software testing for compliance with requirements of the functional. Topicality of relatively new tasks has noticeably grown in recent years in relation to new tasks such as developed product compatibility with various software and hardware platforms, applications, et alia. The second type is usually bound to efficiency and productivity estimation tasks, but in truth, it touches upon a much larger scope of problems - program code bottlenecks detection, detection of resources "leak", etc.

Component and integration testing.

It is obvious, that the first type of testing is carried out on earlier development stages (as finished modules are created), the second - at the finish. Their principal difference consists in the fact that component testing is mainly based on "white box" methods (with due account taken of internal logic and program structure), and integration testing - on "black box" methods (knowledge of interior specifications only). In accordance with that, in the first case a substantial part of work is laid on designers and software developers, in the second - on independent testers.

Manual and automated testing.

As the complexity of a project grows, part of tasks resolved by means of automated methods (usage of scripts, ISS programs) steadily grows. Overwhelming majority of charging testing tasks can be solved exceptionally with their help.

It may have sense to mark out current system configuration testing and testing taking in account its possible development. Possible future problems analysis is often bound to ranging tasks today, for instance increase of system load in the result of user population growth. Yet here one should keep in mind wider range of questions, in particular prospects of platform change. We should stress here that ranging estimation can (and should) be done not only by means of real application testing, but also by system modeling methods on the level of general software structure (they often have forgotten about this approach in recent years).

Solution to the problem - testing centers.

As it has been already said, the leading role in testing issues play methodology and organizational component. As for tools, they play secondary role in this process, and choice of this or that product for testing tasks automation is defined in dependence of aims and specificity of a project, current preferences of a customer, budget. There is a whole spectrum of automated testing means on the market today, and now IBM Rational, Mercury, Segue, Compuware are in the lead. Among competitive software products great attention is now being paid to the most popular IBM Rational Robot system.

Though, in spite of the right methods and tools appliance importance, more topical may be the change of general testing works positioning in the common structure of development process. In particular, it implies the necessity to separate testing as a detached service, implemented on the in-house level or as part of outsourcing. Outsourcing services are quite new for the market, they easily arouse people's interest. So let's enumerate basic principles of interaction:

• accomplishment of the entire software testing work package or its stages on the stand of the Center or on the Customer's land;
• consulting services and customers' training regarding the questions of organizational testing processes within the company;
• testing audit carried out by off-site companies;
• outsourcing of technical and software-based recourses for testing implementation.

Keeping in mind the significance of testing issues, one should remember one of the classics of modern software development methods Dutch professor Edceger Dakestroy, who in the end of 60-s grounded the necessity of structural programming methods appliance based on the task of decreasing man-hours on testing.

Specific character of testing also consists in the fact, that in difference from other stages of software development, having quite formal criteria of their completion, this very process is endless in general. As you know, each last mistake that was found is in reality the last but one. The right position here is to define the necessary scope of testing, and this is a separate complex task.

Speaking about testing, we shouldn't forget about the significance of software verification (a systematic procedure checking the correctness). A slight difference between those notions consists in the fact, that testing is based upon possibilities of comparing the results received and sample ones. Though, there is quite a big class of tasks when there are no samples at all. A classical example of this variant is construction of complex mathematical models with solution of tens of thousands differential equations, but identical situations can also occur when one handles business-applications. In this case it is necessary to include in software additional functions and carry out special research for a user becomes confident that a program works correctly indeed.