What is meant by Holographic Data Storage?

Currently the conventional magnetic and optical data storage dominates the field of high – capacity data storage. But another technology called the holographic data storage holds the potential to lead this area. Now what is this technology? We shall discuss about it in this article. 

Difference between Conventional storage methods and Holographic Data Storage

- The conventional methods such as the optical storage and magnetic storage technologies depend up on the recording of the individual data bits on the distinct optical and magnetic on the medium’s surface. 

- In the holographic technology, the information is recorded throughout the medium’s volume.

- Multiple images can be recorded in the same medium area via utilization of the light at varying angles. 

- Further, in the conventional storage methods the recording takes place in a linear fashion whereas, 

- In holographic storage, millions of bits can be recorded and read in parallel thus increasing the rates of the data transfer more than what are offered by the conventional methods.

Features of Holographic Data Storage

Data Recording: 

- The information is stored in a thick photosensitive optical substance with the help of an optical interference pattern. 

- A laser beam is divided into two un-identical optical patterns (formed of light and dark pixels) and is projected towards the medium. 

- A multitude of holograms in one volume is recorded by making adjustments in the wavelength, reference beam angle, media position etc.

Data Reading: 

- For reading the stored data, the same reference beam is reproduced for the creation of the hologram. 

- This light beam is focused up on the photosensitive material that illuminates the interference pattern which leads to the diffraction of the light. 

- The pattern is then projected to the detector. 

- The data is then read in parallel at a rate more than that of millions. 

- This means high data transfer rate. 

- It takes less than 0.2 seconds for accessing the information from a holographic drive. 

- Holographic data storage has offered a solution to many companies for preserving and archiving the information. 

- The WORM (write – once, read many) approach provides assurance about the content security, risk of modification and overwriting of the information. 

- This technology provides hope for storage of data without degradation for 50 plus years which is quite more than the current options.

- However, if the same trend is followed, and it becomes possible to store data for 50 – 100 years in same format, that would still be irrelevant. 

- This is so because the format will be changing in less than 10 years.  

Types of Holographic Media

- Holographic media is of two types namely:

1.  The re-writable media and
2. The write once medium.

- In the former type, the changes can be reversed but in the latter can the changes are irreversible.

There is no point in the competition between the holographic storage and the hard drives since the former can find a market that is based up on the virtues like access speed. 

- The holographic data storage technology does seems to have a future in the video game market. 

In the year of 2009, the GE Global Research did came up with their own demonstration of the holographic storage medium that could stand the discs that had read mechanisms somewhat similar to that of the blu–ray disc players. 

How test cases are generated using Testing Anywhere?

Testing anywhere software product helps you create the test cases using any of the 5 methods namely:

- Web recording

- Object recording

- Image recognition

- Smart recording and

- Editor

- While editor can be used for editing the test cases by advanced users, wizard is for those who do not have any programming skills. 

- Another facility is that the creation of the files that are executable. 

- These files are created in such a way that they can be executed on a machine that might be located in a remote location. 

- IT and business processes are created by the work flow designer and is managed by the same.

In this article we explain how the test cases can be generated using the testing anywhere product. 

How test cases are generated using Testing Anywhere?

- The testing anywhere product comes with a SMART recorder that one can use to create new tests. 

- Clicking on the ‘record’ button will drop down a list of options from which you have to select what type you are testing i.e., a web or windows application type. 

- Then you need to perform the activities on the system that you want to be recorded. 

- You can insert a checkpoint wherever you want by clicking on the check point button. 

- When you are done with recording the tests click on the stop button. 

- You can then save these activities in a test by clicking on the save button. 

- You can playback these test scripts whenever you want and any number of times by clicking on the run button. 

- In testing anywhere product, it does not matter if any change occurs between the size and location of the window of the application while the recording or replaying is in progress. 

- Testing anywhere uses a SMART automation technology that helps in automatically adjusting to those changes.

- Another advantage of using testing anywhere is that you can work up on any number of applications.

- You do not have to finish working up on one application before moving on to the next. 

- You can very well switch between the applications. 

- Testing anywhere even works while your computer is locked. 

- It does so because of the auto log-in capability that is unique to this software. 

- With this, you can schedule the tests and they will be executed even when your system is locked. 

- If this capability is enabled and the system is locked, it will be unlocked by the testing anywhere, the test will be executed and the computer will be locked again. 

- Auto log-in capability lets you run the tests in stealth mode when the system is locked. To do this follow:

Properties à security à run this test in stealth mode

- The execution will then be hidden. 

- Further, if you want to lock the keyboard and mouse you can use the ‘disable mouse and keyboard for this test’ option. 

- If you want to stop the execution of a test just keep holding the escape key for some time. 

- Using the pause key on the keyboard you can pause the test while it is executing. 

- Further clicking on the resume button you can continue with the execution. 

- Another thing that makes testing anywhere unique is that it can run the tests in background. 

- A number of advanced technologies lets you run the tests in background such as:

1.    Web recorder

2.    Object recorder

3.    And a number of other powerful actions

- However, there are some tests like those that are recorded through standard recorder. 

- These tests require mouse and keyboard control and therefore cannot be executed in background. 

- There are few other exceptions also such as commands such as screenshots; image comparison etc. that cannot be run in background.

What are Selenium components?

Selenium is a portable testing frame work developed by Jason Huggins for automated testing of the web applications. It is specifically a recording and play back tool which eliminates the user’s task of learning a test scripting language. This tool makes use of its own development language popularly known as selenese.

There are 3 major platforms for selenese namely linux, windows and macintosh.

Components of Selenium

The selenium software testing frame work is composed of certain components about which we shall discuss in this article. Following are the components:

1. Selenium IDE: This the selenium’s own integrated development environment dedicated to the creation of the selenium’s tests. This component needs to be implemented as an extension to firefox. Using this IDE, the scripts can either be automatically recorded or edited manually with the help of the IDE’s auto-completion support. It also possesses the ability to quickly move the commands around. However the scripts recorded are in selenese language. This language provides commands basically for two purposes:

a)   For retrieving data from commands to know what actions are to be performed on the web browser such as clicking, linking, selecting an option and so on.

b)   For retrieving data from the result of the actions performed by the commands.

       Its features are:

     a)   Recording and playback tool

     b)   Intelligent field selection

     c)   Autocompletion

     d)   Walk through tests

     e)   Debugging and setting break points

     f)    Saving tests in a number of formats

     g)   Selenium user extension

     h)   Automatic assertion of the page title.

2. Selenium client API: It is not necessary for the tester to develop tests in selenese  only rather he can write tests in any other programming language. The tests thus written will be communicated to selenium through the calling methods provided by selenium client API. Selenium provides this client for the following languages:

   a)   Java

   b)   C#

   c)   Python and

   d)   Ruby

3. Selenium remote control or selenium RC: This component is actually a server implemented in java which retrieves commands via HTTP for a particular browser. With this selenium component it has been made possible to write automated tests regardless of the the programming language for a web application and integrating it with the unit test frame works which already exist. Selenium project comes with client drivers for the following languages in order to make writing tests and easier task:

     a)   PHP

     b)   Python

     c)   Ruby

     d)   .net

     e)   Java and

     f)    Perl

The java driver provides support for the java script also through the rhino   engine. Nowadays a new selenium remote control server is required for launching the HTML test cases which requires for a different port for each of the parallel run. This is in contrast with the PHP and java test case since these require only one continuously running selenium remote control. The selenium B and driven selenium were re-factored by Paul Hammant to develop selenium RC. This also saw the re – implantation of the wire protocol in each of the language ports. After re-factoring, an intermediate daemon processing was done between the browser and the driving test script. As a result driving remote browsers and reducing the need of porting every code statement became possible. Thus the driven selenium was completely taken over by the selenium remote control. 

How to fix the bitmap that failed to stabilize error?

It may happen that the bitmap might fail to stabilize the error in silk test. It is quite a frequently occurring problem but needs to be addressed seriously. 

Most of the times you might have been asked for or required creating a test case that can be straight-forward put to use in carrying out the bitmap verification. 

You set down to create such a test case and go for the verification of the full window while the recording is in progress. 

During the execution of the test case all of a sudden you get an error as stated below:

“Error: bitmap failed to stabilize”

Finding such an error can even be a nightmare for you and sometimes the whole quality assurance team may fail to think of a solution for this. You won’t even find solution for this in the silk test documentation. 

- There are situations that the bitmap issue might be stated in a described state.

- It is only when there is some instability in the verified windows that is to say that some element of the screen is experiencing frequent changes. 

- In such a situation, the stable copy of the bitmap is captured by the silk test automation tool. 

- If in case it could not get the window tested within a specific time interval, then it generates an exception saying “E _ BITMAP _ NOT _ STABLE”.

- Different approaches to such a situation might be used by the different quality assurance engineers. 

- You need to set the below mentioned options to 0 in the 4test code:

Agent. Set option ( OPT _ BITMAP _ MATCH _ COUNT, 0 )

Agent. Set option ( OPT _ BITMAP _ MATCH _ TIME OUT, 0 )

Agent. Set option ( OPT _ BITMAP _ MATCH _ INTERVAL, 0 )

- Another way of doing this is going to the options menu, then agent, then bitmap and change the required values. 

- Another error occurs while capturing image via the capture bitmap method. 

- In some cases when this method was executed the silk test was observed giving the following error:

“bitmap region size (some coordinate) is not valid”

- In such a case the getrect method can be used for obtaining the coordinates of the bitmap. 

- The getrect method returns the following:

1. X coordinate of the active bitmap
2. Y coordinate of the active bit map
3. Width of the active image
4. Height of the active image

- For capturing an image, one requires two coordinates of the image i.e., (x1, y1) and (x2, y2).

- Here the coordinates correspond as follow:
1. First co-ordinate is for the top left corner of the image whereas

2. The second coordinate points to the right bottom corner of the image. 

- You can even take help of the identify object feature of the silk test workbench for discovering these coordinates. 

- To avoid these errors it is necessary that you fix the screen resolution in the first go itself i.e., using the first script itself using the following function:

Maximize()

- Once this function has been implemented, and then you should go for capturing the screen shot. 

- If this is not done then there are chances that the screen size may keep on changing i.e., it may expand or shrink according to the settings that you made for the previous scripts. 

- This may also cause the coordinates to shift on the screen which may cause the script to capture something else than what was expected. 

- However, the getrect method can return both absolute as well as the relative methods. 

How Silk Test records user actions?

Software systems or applications as we all know are composed of a GUI or graphical user interface objects such as those mentioned below:

1. Windows
2. Menus
3. Buttons and so on.

These GUI objects can be manipulated by the user via a mouse or a key board for initiating the operations on an application.

These GUI objects are interpreted by the silk test and are recognized in to different categories based up on the following aspects that uniquely identify them:

1. Class
2. Properties and
3. Methods

While the testing is in progress, an interaction takes place among the silk test and the GUI objects so that the operations can be submitted to the application under testing or AUT automatically without much efforts and also because the actions of a user can be simulated. 

This is also done to verify the results of each and every operation. The silk test is said to be the simulated user which is then said to drive the application under test or AUT. 

The silk test comes with two distinct components namely:

1. The silk test host software
2. The silk test agent software

- The first component of the silk test i.e., the silk test host software is used for developing, editing, compiling, running and debugging of the test plans as well as the test scripts. 

- The machine on which this component is installed is called the host machine. - The latter component of the silk test i.e., the silk test agent is the one that interacts with the graphical user interface of the application under test. 

- The commands present in the 4test scripts of the application are translated in to GUI specific commands which help in driving and monitoring the application under test.

- It is possible to run the agent locally on the same machine on which the host is already running or else it can be run in a networked environment. 

- But in this case, the machine will be known as the remote machine. 

How the user actions are recorded by the silk test?

 

- A repository is created for storing the information regarding the application under test or AUT before the test scripts are created and executed. 

- This repository consists of the descriptions of the GUI objects that are responsible for compromising with your application under test. 

- The silk test associates with these objects by means of two things namely:

1. Object properties and
2. Object methods

- Using these two aspects the actions performed on the objects can be easily recognized by the silk test and can be intelligently recorded in to the test script using the 4test language. 

Below we are giving some examples of what is recorded by the silk test for some user actions:

-User action	As recorded by the silk test
-Selection of a radio button from a group	select
-Setting the main window as active	Set Active
-Closing a dialog box	close
-Selecting an item from a list box	Select
-Scrolling the scroll bar to the maximum position possible	Scroll to max
-Writing text in a text field	Set text
-Checking a check box	Check
-Picking a menu item	pick
-Unchecking a check box	uncheck

- A property is that characteristic of an object that can be accessed directly and may be common among some classes. 

- On the other hand, the methods constitute of the user actions and are particular to an object. 

- Methods that are particular to an object are inherited from the parent class of the object. 

- Methods are unique to the objects of a class. 

What is a Test Object Model in QTP?

Test object model is an important concept of quick test professional to be understood. In this article we have focused on the test object model of the quick test professional itself. 

What is a Test Object Model?

- The test object model is considered to be a large set of classes or objects of type class which are used by the quick test professional to represent the objects present in the software system or application.

- There is a list of properties associated with every class of the test object. 

- Using the properties from this property list, the objects belonging to that particular class can be uniquely identified. 

- Also, the identification of a set of relevant methods that can be recorded for the object by the quick test professional can be easily identified. 

First let us clear up few terms associated with the test object model one by one:

1. Test object: 

This is the object that is created by the quick test professional in the test component or the test as a means of representation of the actual object present in the AUT or application under test. The information regarding the object is stored by the quick test professional since later it is required for many purposes like identification of the object and checking the working of the object during the run session.

    2. Run time object: 

   This object is the actual object present in the application under test. On this object only the various methods are performed while the identification process is in progress or we can say during the run session.

Whenever the user carries out an operation on an object in the application, the  following steps are taken by the quick test professional:

a)    Identification of the test object class of the quick test professional which is said to represent the object up on which the user performed the desired operation.

b)   Creation of appropriate test object based up on the identification in the previous step.

c)     Capturing of the current values of the properties of the objects residing in the application under test and preparing a list accordingly. This list is then saved along with the test object.

d)   Giving of a unique name to the test object up on the condition that it should reflect the value of one of the objects prominent properties.

e)    Recording of the operations that the user carried out on the test object by making use of the appropriate quick test professional test object method.

There are certain points about the test object model which are always helpful:

1. Each and every test object method that is executed during the recording session forms a separate step in the recorded test. When the command for execution of the test is encountered, this recorded test object method is played up on the run time object.
2. The source from where the properties of the object are captured is the object itself. These properties are important since there values are used for the identification of the run time objects while a run session is in progress.
3. The properties of the objects have a tendency to change during the run session and so this would present some difficulty while matching the objects with the description. To avoid such a situation you have the option to make a manual modification of the test object properties while designing the test component during a run session. Some times even the regular expressions can be used as a substitute for the identification of the property values.
4. The test object property values can be viewed as well as modified and stored through the object repository dialog box. 

Explain the concept of object repository & how QTP recognizes objects?

Just like its Winrunner counterpart, the quick test professional also comes with an object repository which is the first aspect of this article that we are going to discuss in this article and the second aspect to be discussed is regarding the identification of the objects by the quick test professional. 

What is a Object Repository?

- Just like we have a store room and other storage places in our house, the same way the quick test professional consists of a storage place where the information regarding the objects can be stored and this storage place is called the “object repository”. 

- During the process of the identification of the objects, the presence of an interface is necessary between the application under test and test scripts in order for proper identification of the objects. 

- This interface is provided by none other than the object repository itself. 

- An object can be identified as a run time entity with some characteristic properties as well as structure. 

- Few examples of software objects are:

1. Windows
2. Web pages
3. Edit boxes
4. Buttons
5. Check boxes and so on.

What kind of objects QTP recognizes?

Quick test professional recognizes 4 types of objects as mentioned below:

1. Run time objects

These are the objects that are present in the application under test or AUT such as links, check boxes, buttons etc.

2. Test objects

-Run time objects cannot be operated up on directly rather there references are created which are nothing but the test objects such as web button, link, win edit and so on. 

-These test objects are referenced by different names in different environments.

3. Utility Objects

- These are the objects that are reserved by the quick test professional for the purpose of testing as well as test reporting. 

- One such example is the reporter object for displaying the test results.

4. User defined objects (also known as the automation objects)

- In most of the cases objects are required that can perform some specific operations i.e., the user defined operations. 

- Such objects are referred to as the user defined objects.

How QTP recognizes objects?

- For every action that is performed on an object, a local repository is created by the quick test professional automatically while the recording is in progress.

- The local object repository is different from the global object repository in the respect that it cannot be shared among the tests.

- Additional objects can be added to this repository by the user as well as the existing ones can be modified. 

- Global object repository is more commonly known as the shared repository. 

Now let us focus up on the second aspect of the quick test professional i.e., the identification of the objects. 

- Quick test professional has got two major mechanisms for accomplishing this task as stated below:

1. Usual object identification mechanism

- In this mechanism, the learned description of the object i.e., the one provided by user is followed throughout the identification process for identifying the object. 

2. The smart identification mechanism

- This mechanism is smarter than the former one, more flexible but far complex. 

- It comes into play when the first one fails. 

- It rejects the description that was used in the first mechanism and prepares a list of objects that resembles properties defined by the quick test professional. - For the smart identification process to work properly it is required that it should be configured properly. 

What are the advantages and drawbacks of QTP?

Though the quick test professional is quite useful like every other object in this world, it has got its advantages and drawbacks. The same thing is going to be discussed here in this article. 

Advantages of Quick Test Professional

1. The quick test professional has got such simplicity that it can be understood easily by even a non programmer and can begin with the testing by adding the test cases.

2. The quick test professional provides support for record and playback of the scripts. Plus it comes with the ability to edit the scripts just after the recording is complete. Different recording modes or options are available with the quick test professional:

    a)   Normal or context sensitive recording mode

    b)   Analog recording mode and

    c)   Low level recording mode

3. Quick test professional (QTP) possesses an excellent object identification mechanism.

4. Quick test professional comes with an extended support for the following add ins:

    a)   SAP

    b)   Oracle

    c)   Java

    d)   .NET

    e)   Siebel

    f)    Main frame or terminal emulators

    g)   Web services

    h)   Web forms and so on.

5. With quick test professional the existing tests and test scripts can be enhanced even if the AUT or application under test in not there with the help of an active screen.

6. Almost all of the popular test automation frame works (such as key word driven, data driven, modular testing approach, hybrid and so on) are supported by the quick test professional.

7. An IDE or integrated development environment is inbuilt in to the quick test professional which is quite easy to use and has got a simple interface. 

8.The scripting language “VBScript” which is used by the quick test professional is just like English and can be learned easily. There are plenty of sources via which one can learn VBScript.

9. In many of the test automation suites it is found difficult to implant the MOM i.e., the Microsoft object model but in quick test professional it is an easy task to do.

10.To make quick test professional further better it can be embellished with other test management tools such as the HP QC or quality center, functional testing tools such as winrunner and test management tools such as test director and so on. Once the tests have been mapped to the automation scripts, they can be executed directly from the HP quality center. Also, winrunner test execution can be kicked off by the quick test professional.

11.With quick test professional several types of suites can be maintained namely:

    a)   Sanity

    b)   Smoke

    c)   Regression and so on.

12. Like most of the test automation suites it provides support for xml.

13. Excel or data base files can be used easily in quick test professional with a variety of methods to use them.

14. Data and the test iterations can be easily maintained.

15. Test reports provided by the quick test professional are complete with all details required for analysis.

Drawbacks of Quick Test Professional

1. Proves to be costlier than any other test automation suite in terms of license and maintenance.

2. It does not support multiple threads and instances execution.

3. It will be surprising to know that the quick test professional has got no high speed rather it has got much slower speed than most of the open source tools such as selenium.

4. Support is provided from HP QC only on the renewal of the license.

5. Add- ins (such as SAP, oracle, java, .net, Seibel, peoplesoft and so on) have to be purchased separately.