Introduction to Integration Testing

Introduction to Integration Testing:

When the modules are under the process of development, the developers develop some interfaces and integrate the module with the help of those interfaces. Here integration is the process of assembling unit-tested modules. We need to test the following aspects, which have not been addressed previously while independently testing the modules:

• Interfaces: To ensure "interface integrity," the transfer of data between modules is tested. When data is passed to another module, by way of a call, there should not be any loss or corruption of data. The loss or corruption of data can happen due to mis-match or differences in the number or order of calling and receiving parameters.
• Module combinations may produce a different behavior due to combinations of data that are not exercised during unit testing.

Global data structures, if used, may reveal errors due to unintended usage in some module.

Integration Testing falls under the category of white box testing.

Following four approaches are generally adopted by the developers while integrating the modules.

To illustrate the methodology, let us consider the following arrangement of modules say M1, M2, M3 ……. M7:

1) Top Down Approach (TDA):
Involves development of all the topmost / parent modules before hand followed by due integration with child modules.

This approach uses a Program called "Stub". While integrating the modules with this Top Down Approach, if at any stage it is found that some mandatory module is missing, then in such an event that particular module is replaced with a temporary program known as "Stub".

The testing starts with M1. To test M1 in isolation, communications to modules M2, M3 and M4 needs to be simulated by the tester by some means, since these modules may not be ready yet. To simulate responses of M2, M3 and M4 whenever they are to be invoked from M1, "stubs" are created. Simple applications may require stubs, which would simply return the control to their superior modules. More complex situation demand stubs to simulate a full range of responses, including parameter passing. Stubs may be individually created by the tester or they may be provided by a software testing harness, which is a sort of software specifically designed to provide a testing environment.

In the above illustration, M1 would require stubs to simulate the activities of M2, M3 and M4. The integration of M3 would require a stub or stubs for M5 and M4 would require stubs for M6 and M7. Elementary modules i.e. the modules which do not call subordinates would not require any stubs.

Advantages of Top down Approach:

a) This approach is advantageous if all major flaws are captured towards the top of the program

b) Early skeletal program allows demonstrations and boosts the morale

Disadvantages of Top down Approach:

a) Stub modules are essential

b) Test conditions my be impossible, or very difficult, to create

c) Observation of test output is more difficult, as only simulated values will be used initially. For the same reason, program correctness can be misleading

2) Bottom Up Approach (BUA):
Involves development of all the elementary modules or child modules before hand followed by due integration with the corresponding parent modules.

This approach uses a Program called "Driver". While integrating the modules with this Bottom Up Approach, if at any stage it is found that some mandatory module is missing, then in such an event that particular module is replaced with a temporary program known as "Driver".

If M5 is ready, we need to simulate the activities of its superior, M3. Such a "driver" for M5 would simulate the invocation activities of M3. As with the stub, the complexity of a driver would depend upon the application under test. The driver would be responsible for invoking the module under test, it could be responsible for passing test data and it might be responsible for receiving output data. Here as well, the driving function can be provided through a testing harness or may be created by the tester as a program.

For the above-mentioned Bottom-Up example, drivers must be provided for modules M2, M5, M6, M7, M3 and M4. However there is no need for a driver for the topmost Module, M1.

Advantages of Bottom Up Approach:

a) This approach is advantageous if all major flaws are captured towards the bottom of the program

b) Test conditions are easier to create

c) Observations of test results are easier since "live" data is used from the beginning.

Disadvantages of Bottom Up Approach:

a) Driver modules are essential>

b) The program as an entity does not exist until the last module is added

3) Big Bang Approach:
Once all the modules are ready after testing individually; the approach of integrating them finally at once is known as big bang approach.

Though Big Bang approach seems to be advantageous when we construct independent module concurrently, this approach is quite challenging and risky as we integrate all modules in a single step and test the resulting system. Locating interface errors, if any, becomes difficult here.

4) Hybrid Approach:
To overcome the limitations and to exploit the advantages of Top-down and Bottom-up approaches, a hybrid approach in testing is used. As the name suggests, it is a mixture of the two approaches like Top Down approach as well as Bottom Up approach.

In this approach the system is viewed as three layers consisting of the main target layer in the middle, another layer above the target layer, and the last layer below the target layer.

The Top-Down approach is used in the topmost layer and Bottom-Up approach is used in the lowermost layer. The lowermost layer contains many general-purpose utility programs, which are helpful in verifying the correctness during the beginning of testing.

Testing converges for the middle level target layers are selected on the basis of system characteristics and the structure of the code. The middle level target layer contains components using the utilities.

Final decision on selecting an integration approach depends on system characteristics as well as on customer expectations. Sometimes the customer wants to see a working version of the application as soon as possible thereby forcing an integration approach aimed at producing a basic working system in the earlier stages of the testing process.

Web Testing: Complete guide on testing web applications

Let’s have first web testing checklist.
1) Functionality Testing
2) Usability testing
3) Interface testing
4) Compatibility testing
5) Performance testing
6) Security testing

1) Functionality Testing:

Test for - all the links in web pages, database connection, forms used in the web pages for submitting or getting information from user, Cookie testing.

Check all the links:

• Test the outgoing links from all the pages from specific domain under test.
• Test all internal links.
• Test links jumping on the same pages.
• Test links used to send the email to admin or other users from web pages.
• Test to check if there are any orphan pages.
• Lastly in link checking, check for broken links in all above-mentioned links.

Test forms in all pages:
Forms are the integral part of any web site. Forms are used to get information from users and to keep interaction with them. So what should be checked on these forms?

• First check all the validations on each field.
• Check for the default values of fields.
• Wrong inputs to the fields in the forms.
• Options to create forms if any, form delete, view or modify the forms.

Let’s take example of the search engine project currently I am working on, In this project we have advertiser and affiliate signup steps. Each sign up step is different but dependent on other steps. So sign up flow should get executed correctly. There are different field validations like email Ids, User financial info validations. All these validations should get checked in manual or automated web testing.

Cookies testing:
Cookies are small files stored on user machine. These are basically used to maintain the session mainly login sessions. Test the application by enabling or disabling the cookies in your browser options. Test if the cookies are encrypted before writing to user machine. If you are testing the session cookies (i.e. cookies expire after the sessions ends) check for login sessions and user stats after session end. Check effect on application security by deleting the cookies. (I will soon write separate article on cookie testing)

Validate your HTML/CSS:
If you are optimizing your site for Search engines then HTML/CSS validation is very important. Mainly validate the site for HTML syntax errors. Check if site is crawlable to different search engines.

Database testing:
Data consistency is very important in web application. Check for data integrity and errors while you edit, delete, modify the forms or do any DB related functionality.
Check if all the database queries are executing correctly, data is retrieved correctly and also updated correctly. More on database testing could be load on DB, we will address this in web load or performance testing below.

2) Usability Testing:

Test for navigation:
Navigation means how the user surfs the web pages, different controls like buttons, boxes or how user using the links on the pages to surf different pages.
Usability testing includes:
Web site should be easy to use. Instructions should be provided clearly. Check if the provided instructions are correct means whether they satisfy purpose.
Main menu should be provided on each page. It should be consistent.

Content checking:
Content should be logical and easy to understand. Check for spelling errors. Use of dark colors annoys users and should not be used in site theme. You can follow some standards that are used for web page and content building. These are common accepted standards like as I mentioned above about annoying colors, fonts, frames etc.
Content should be meaningful. All the anchor text links should be working properly. Images should be placed properly with proper sizes.
These are some basic standards that should be followed in web development. Your task is to validate all for UI testing

Other user information for user help:
Like search option, sitemap, help files etc. Sitemap should be present with all the links in web sites with proper tree view of navigation. Check for all links on the sitemap.
“Search in the site” option will help users to find content pages they are looking for easily and quickly. These are all optional items and if present should be validated.

3) Interface Testing:
The main interfaces are:
Web server and application server interface
Application server and Database server interface.

Check if all the interactions between these servers are executed properly. Errors are handled properly. If database or web server returns any error message for any query by application server then application server should catch and display these error messages appropriately to users. Check what happens if user interrupts any transaction in-between? Check what happens if connection to web server is reset in between?

4) Compatibility Testing:
Compatibility of your web site is very important testing aspect. See which compatibility test to be executed:

• Browser compatibility
• Operating system compatibility
• Mobile browsing
• Printing options

Browser compatibility:
In my web-testing career I have experienced this as most influencing part on web site testing.
Some applications are very dependent on browsers. Different browsers have different configurations and settings that your web page should be compatible with. Your web site coding should be cross browser platform compatible. If you are using java scripts or AJAX calls for UI functionality, performing security checks or validations then give more stress on browser compatibility testing of your web application.
Test web application on different browsers like Internet explorer, Firefox, Netscape navigator, AOL, Safari, Opera browsers with different versions.

OS compatibility:
Some functionality in your web application is may not be compatible with all operating systems. All new technologies used in web development like graphics designs, interface calls like different API’s may not be available in all Operating Systems.
Test your web application on different operating systems like Windows, Unix, MAC, Linux, Solaris with different OS flavors.

Mobile browsing:
This is new technology age. So in future Mobile browsing will rock. Test your web pages on mobile browsers. Compatibility issues may be there on mobile.

Printing options:
If you are giving page-printing options then make sure fonts, page alignment, page graphics getting printed properly. Pages should be fit to paper size or as per the size mentioned in printing option.

5) Performance testing:
Web application should sustain to heavy load. Web performance testing should include:
Web Load Testing
Web Stress Testing

Test application performance on different internet connection speed.
In web load testing test if many users are accessing or requesting the same page. Can system sustain in peak load times? Site should handle many simultaneous user requests, large input data from users, Simultaneous connection to DB, heavy load on specific pages etc.

Stress testing: Generally stress means stretching the system beyond its specification limits. Web stress testing is performed to break the site by giving stress and checked how system reacts to stress and how system recovers from crashes.
Stress is generally given on input fields, login and sign up areas.

In web performance testing web site functionality on different operating systems, different hardware platforms is checked for software, hardware memory leakage errors,

6) Security Testing:

Following are some test cases for web security testing:

• Test by pasting internal url directly into browser address bar without login. Internal pages should not open.
• If you are logged in using username and password and browsing internal pages then try changing url options directly. I.e. If you are checking some publisher site statistics with publisher site ID= 123. Try directly changing the url site ID parameter to different site ID which is not related to logged in user. Access should denied for this user to view others stats.
• Try some invalid inputs in input fields like login username, password, input text boxes. Check the system reaction on all invalid inputs.
• Web directories or files should not be accessible directly unless given download option.
• Test the CAPTCHA for automates scripts logins.
• Test if SSL is used for security measures. If used proper message should get displayed when user switch from non-secure http:// pages to secure https:// pages and vice versa.
• All transactions, error messages, security breach attempts should get logged in log files somewhere on web server.

REMEMBER SOFTWARE TESTING 10 RULES

1. Test early and test often.
2. Integrate the application development and testing life cycles. You’ll get better results and you won’t have to mediate between two armed camps in your IT shop.
3. Formalize a testing methodology; you’ll test everything the same way and you’ll get uniform results.
4. Develop a comprehensive test plan; it forms the basis for the testing methodology.
5. Use both static and dynamic testing.
6. Define your expected results.
7. Understand the business reason behind the application. You’ll write a better application and better testing scripts.
8. Use multiple levels and types of testing (regression, systems, integration, stress and load).
9. Review and inspect the work, it will lower costs.
10. Don’t let your programmers check their own work; they’ll miss their own errors.

Website Cookie Testing

What is Cookie?

Cookie is small information stored in text file on user’s hard drive by web server. This information is later used by web browser to retrieve information from that machine. Generally cookie contains personalized user data or information that is used to communicate between different web pages.

Why Cookies are used?
Cookies are nothing but the user’s identity and used to track where the user navigated throughout the web site pages. The communication between web browser and web server is stateless.

For example if you are accessing domain http://www.example.com/1.html then web browser will simply query to example.com web server for the page 1.html. Next time if you type page as http://www.example.com/2.html then new request is send to example.com web server for sending 2.html page and web server don’t know anything about to whom the previous page 1.html served.

What if you want the previous history of this user communication with the web server? You need to maintain the user state and interaction between web browser and web server somewhere. This is where cookie comes into picture. Cookies serve the purpose of maintaining the user interactions with web server.

How cookies work?
The HTTP protocol used to exchange information files on the web is used to maintain the cookies. There are two types of HTTP protocol. Stateless HTTP and Stateful HTTP protocol. Stateless HTTP protocol does not keep any record of previously accessed web page history. While Stateful HTTP protocol do keep some history of previous web browser and web server interactions and this protocol is used by cookies to maintain the user interactions.

Whenever user visits the site or page that is using cookie, small code inside that HTML page (Generally a call to some language script to write the cookie like cookies in JAVAScript, PHP, Perl) writes a text file on users machine called cookie.
Here is one example of the code that is used to write cookie and can be placed inside any HTML page:

Set-Cookie: NAME=VALUE; expires=DATE; path=PATH; domain=DOMAIN_NAME;

When user visits the same page or domain later time this cookie is read from disk and used to identify the second visit of the same user on that domain. Expiration time is set while writing the cookie. This time is decided by the application that is going to use the cookie.

Generally two types of cookies are written on user machine.

1) Session cookies: This cookie is active till the browser that invoked the cookie is open. When we close the browser this session cookie gets deleted. Some time session of say 20 minutes can be set to expire the cookie.
2) Persistent cookies: The cookies that are written permanently on user machine and lasts for months or years.

Where cookies are stored?
When any web page application writes cookie it get saved in a text file on user hard disk drive. The path where the cookies get stored depends on the browser. Different browsers store cookie in different paths. E.g. Internet explorer store cookies on path “C:\Documents and Settings\Default User\Cookies”
Here the “Default User” can be replaced by the current user you logged in as. Like “Administrator”, or user name like “Vijay” etc.
The cookie path can be easily found by navigating through the browser options. In Mozilla Firefox browser you can even see the cookies in browser options itself. Open the Mozila browser, click on Tools->Options->Privacy and then “Show cookies” button.

How cookies are stored?
Lets take example of cookie written by rediff.com on Mozilla Firefox browser:
On Mozilla Firefox browser when you open the page rediff.com or login to your rediffmail account, a cookie will get written on your Hard disk. To view this cookie simply click on “Show cookies” button mentioned on above path. Click on Rediff.com site under this cookie list. You can see different cookies written by rediff domain with different names.

Site: Rediff.com Cookie name: RMID
Name: RMID (Name of the cookie)
Content: 1d11c8ec44bf49e0… (Encrypted content)
Domain: .rediff.com
Path: / (Any path after the domain name)
Send For: Any type of connection
Expires: Thursday, December 31, 2020 11:59:59 PM

Applications where cookies can be used:

1) To implement shopping cart:
Cookies are used for maintaining online ordering system. Cookies remember what user wants to buy. What if user adds some products in their shopping cart and if due to some reason user don’t want to buy those products this time and closes the browser window? When next time same user visits the purchase page he can see all the products he added in shopping cart in his last visit.

2) Personalized sites:
When user visits certain pages they are asked which pages they don’t want to visit or display. User options are get stored in cookie and till the user is online, those pages are not shown to him.

3) User tracking:
To track number of unique visitors online at particular time.

4) Marketing:
Some companies use cookies to display advertisements on user machines. Cookies control these advertisements. When and which advertisement should be shown? What is the interest of the user? Which keywords he searches on the site? All these things can be maintained using cookies.

5) User sessions:
Cookies can track user sessions to particular domain using user ID and password.

Drawbacks of cookies:

1) Even writing Cookie is a great way to maintain user interaction, if user has set browser options to warn before writing any cookie or disabled the cookies completely then site containing cookie will be completely disabled and can not perform any operation resulting in loss of site traffic.

2) Too many Cookies:
If you are writing too many cookies on every page navigation and if user has turned on option to warn before writing cookie, this could turn away user from your site.

3) Security issues:
Some times users personal information is stored in cookies and if someone hack the cookie then hacker can get access to your personal information. Even corrupted cookies can be read by different domains and lead to security issues.

4) Sensitive information:
Some sites may write and store your sensitive information in cookies, which should not be allowed due to privacy concerns.

This should be enough to know what cookies are. If you want more cookie info see Cookie Central page.

Some Major Test cases for web application cookie testing:

The first obvious test case is to test if your application is writing cookies properly on disk. You can use the Cookie Tester application also if you don’t have any web application to test but you want to understand the cookie concept for testing.

Test cases:

1) As a Cookie privacy policy make sure from your design documents that no personal or sensitive data is stored in the cookie.

2) If you have no option than saving sensitive data in cookie make sure data stored in cookie is stored in encrypted format.

3) Make sure that there is no overuse of cookies on your site under test. Overuse of cookies will annoy users if browser is prompting for cookies more often and this could result in loss of site traffic and eventually loss of business.

4) Disable the cookies from your browser settings: If you are using cookies on your site, your sites major functionality will not work by disabling the cookies. Then try to access the web site under test. Navigate through the site. See if appropriate messages are displayed to user like “For smooth functioning of this site make sure that cookies are enabled on your browser”. There should not be any page crash due to disabling the cookies. (Please make sure that you close all browsers, delete all previously written cookies before performing this test)

5) Accepts/Reject some cookies: The best way to check web site functionality is, not to accept all cookies. If you are writing 10 cookies in your web application then randomly accept some cookies say accept 5 and reject 5 cookies. For executing this test case you can set browser options to prompt whenever cookie is being written to disk. On this prompt window you can either accept or reject cookie. Try to access major functionality of web site. See if pages are getting crashed or data is getting corrupted.

6) Delete cookie: Allow site to write the cookies and then close all browsers and manually delete all cookies for web site under test. Access the web pages and check the behavior of the pages.

7) Corrupt the cookies: Corrupting cookie is easy. You know where cookies are stored. Manually edit the cookie in notepad and change the parameters to some vague values. Like alter the cookie content, Name of the cookie or expiry date of the cookie and see the site functionality. In some cases corrupted cookies allow to read the data inside it for any other domain. This should not happen in case of your web site cookies. Note that the cookies written by one domain say rediff.com can’t be accessed by other domain say yahoo.com unless and until the cookies are corrupted and someone trying to hack the cookie data.

8 ) Checking the deletion of cookies from your web application page: Some times cookie written by domain say rediff.com may be deleted by same domain but by different page under that domain. This is the general case if you are testing some ‘action tracking’ web portal. Action tracking or purchase tracking pixel is placed on the action web page and when any action or purchase occurs by user the cookie written on disk get deleted to avoid multiple action logging from same cookie. Check if reaching to your action or purchase page deletes the cookie properly and no more invalid actions or purchase get logged from same user.

9) Cookie Testing on Multiple browsers: This is the important case to check if your web application page is writing the cookies properly on different browsers as intended and site works properly using these cookies. You can test your web application on Major used browsers like Internet explorer (Various versions), Mozilla Firefox, Netscape, Opera etc.

10) If your web application is using cookies to maintain the logging state of any user then log in to your web application using some username and password. In many cases you can see the logged in user ID parameter directly in browser address bar. Change this parameter to different value say if previous user ID is 100 then make it 101 and press enter. The proper access message should be displayed to user and user should not be able to see other users account.

These are some Major test cases to be considered while testing website cookies. You can write multiple test cases from these test cases by performing various combinations. If you have some different application scenario, you can mention your test cases in comments below.

Read More about Software Testing Tutorials