Equivalence Class Partitioning with example

What is "Equivalence Class Partitioning"?

We define "Equivalence Class Partitioning" as a method that can help you derive test cases. You identify classes of input or output conditions. The rule is that each member in the class causes the same kind of behavior of the system. In other words, the "Equivalence Class Partitioning" method creates sets of inputs or outputs that are handled in the same way by the application.

Another definition taken from Wikipedia:
"A technique in black box testing. It is designed to minimize the number of test cases by dividing tests in such a way that the system is expected to act the same way for all tests of each equivalence partition. Test inputs are selected from each class. Every possible input belongs to one and only one equivalence partition."

Why learn "Equivalence Class Partitioning"?

This method drastically reduces the number of test cases that are required to be tested because we don't have time, money or manpower to test everything. In addition, it can help you find many errors with the smallest number of test cases.
How to use "Equivalence Class Partitioning"?

There are 2 major steps we need to do in order to use equivalence class partitioning:

• Identify the equivalence classes of input or output. Take each input's or output's condition that is described in the specification and derive at least 2 classes for it:
  • One class that satisfies the condition – the valid class.
  • Second class that doesn't satisfy the condition – the invalid class.
• Design test cases based on the equivalence classes.

Example 1

In a computer store, the computer item can have a quantity between -500 to +500. What are the equivalence classes?

Answer: Valid class: -500 <= QTY <= +500
                Invalid class: QTY > +500
                Invalid class: QTY < -500

Example 2

In a computer store, the computer item type can be P2, P3, P4, and P5 (each type influences the price). What are the equivalence classes?

Answer: Valid class: type is P2
                Valid class: type is P3
                Valid class: type is P4
                Valid class: type is P5
                Invalid class: type isn’t P2, P3, P4 or P5

Practice

Bank account can be 500 to 1000 or 0 to 499 or 2000 (the field type is integer). What are the equivalence classes?

Try to solve it before reading the answer.

Practice 1 - answer

• Valid class: 0 <= account <= 499
• Valid class: 500 <= account <= 1000
• Valid class: 2000 <= account <= 2000
• Invalid class: account < 0
• Invalid class: 1000 < account < 2000
• Invalid class: account > 2000

Equivalence Class Vs Boundary Testing

Let us discuss about the difference between Equivalence class and boundary testing. For the discussion we will use the practice question:

Bank account can be integer in the following ranges: 500 to 1000 or 0 to 499 or 2000. What are the equivalence classes?

Answer:

• valid class: 0 <= account <= 499
• valid class: 500 <= account <= 1000
• valid class: 2000 <= account <= 2000
• invalid class: account < 0
• invalid class: 1000 < account < 2000
• invalid class: account > 2000

In equivalence class, you need to take one value from each class and test whether the value causes the system to act as the class' definition. It means that in this example, you need to create at least 6 test cases – one for each valid class and one for each invalid class.

How many test cases will be, if you use boundary testing?

The following table shows how much test cases will be using "Boundary Testing" method:

Test Case #	Value	Result
1	-1	Invalid
2	0	Valid
3	1	Valid
4	498	Valid
5	499	Valid
6	500	Valid
7	501	Valid
8	999	Valid
9	1000	Valid
10	1001	Invalid
11	1999	Invalid
12	2000	Valid
13	2001	Invalid

In boundary testing, you need to test each value in the boundary and you know the value, you don't need to choose it from any set. In this example you have 13 test cases.

Now, let us exam how to combine this 2 methods together.

The following table shows all the boundary testing values and their equivalence classes:

#	Boundary Value	Equivalence Class	Result
1	-1	account < 0	Invalid
2	0	0 <= account <= 499	Valid
3	1	0 <= account <= 499	Valid
4	498	0 <= account <= 499	Valid
5	499	0 <= account <= 499	Valid
6	500	500 <= account <= 1000	Valid
7	501	500 <= account <= 1000	Valid
8	999	500 <= account <= 1000	Valid
9	1000	500 <= account <= 1000	Valid
10	1001	1000 < account < 2000	Invalid
11	1999	1000 < account < 2000	Invalid
12	2000	2000 <= account <= 2000	Valid
13	2001	account > 2000	Invalid

Now, we can reduce some of the test cases that belong to the same equivalence class. We can delete lines 3 and 4 which belong to equivalence class "0 <= account <= 499". We also can delete lines 7 and 8 hich belong to "500 <= account <= 1000". The new table will be:

#	Boundary Value	Equivalence Class	Result
1	-1	account < 0	Invalid
2	0	0 <= account <= 499	Valid
5	499	0 <= account <= 499	Valid
6	500	500 <= account <= 1000	Valid
9	1000	500 <= account <= 1000	Valid
10	1001	1000 < account < 2000	Invalid
11	1999	1000 < account < 2000	Invalid
12	2000	2000 <= account <= 2000	Valid
13	2001	account > 2000	Invalid

You can even reduce more test cases although in my opinion, it is important to keep this table because it keeps a hard connection to the boundary testing. You can see in the table that I didn't reduce those test cases that are touch in the boundary itself of each range.

Let's reduce more test cases (just for the fun and for the practice (test case 5, 9 and 10):

#	Boundary Value	Equivalence Class	Result
1	-1	account < 0	Invalid
2	0	0 <= account <= 499	Valid
6	500	500 <= account <= 1000	Valid
11	1999	1000 < account < 2000	Invalid
12	2000	2000 <= account <= 2000	Valid
13	2001	account > 2000	Invalid

Now, in this table, for each equivalence class, you choose one value that belongs to boundary testing.

Boundary Values Testing with example

What is “Boundary Values Testing”?
 
“Boundary Values Testing” is a method that tests the boundary whether it's an input, an output or a performance boundary. Our tests focus on the boundaries values and not on the entire range of data. We will use it when we have a field that can contain a range of values as an input, an output or as a requirement.

How to use “Boundary Values Testing”?
 
If you have a range: (a to b), you will test the following:

Test Case	Value	Expected Result
1	a-1	Invalid
2	a	Valid
3	a+1	Valid
4	b-1	Valid
5	b	Valid
6	b+1	Invalid

According to the ISTQB in "Boundary Values Testing" we only test the following:

Test Case	Value	Expected Result
1	a-1	Invalid
2	a	Valid
3	b	Valid
4	b+1	Invalid

Why ISTQB has less test cases, because we can say that if 'a' and 'a-1' are working well, then we can assume that 'a+1' is working well. The same claim will be about the upper bound. If 'b' and 'b+1' are working well, then we can assume that 'b-1' is working well.
Any option of implementing the "Boundary Values" method you will use is good. Instead of testing the entire range, you can tests 6 or 4 cases and still have confiedence that the software works well.
Here are some more rules from my experience that you can take in consideration:

• Always test 0 if it is inside the range and sometimes even if it's out of range because 0 has special effect on software (like dividing in 0).
• Always test the empty string if it is inside the range and sometimes even if it's out of range.
• Sometimes you can test a value that exists inside the range and not in the boundary just in case…(It allows you to sleep deeper at night…).

Now, let us practice the "Boundary Values Testing" method.
Practice 1
You are testing inventory software that contains a field of the quantity of items. The field can contain any value between 10 to 100 units.

• What is the max number of test cases you will need in order to test the field?
• What is the minimum number of test cases you will need in order to test the field, using boundary testing?

Try to solve it and then continue to read the answer.
Practice 1 - answer
The field contains a range of 10 to 100 (10-100).

• The max number of test cases you will need in order to test the field will be 93 test cases (9, 10, 11, 12…97, 98, 99, 100, 10) or 94 test cases if we include the value of 0.
• The minimum number of test cases you will need in order to test the field, using boundary testing will be 6 test cases (9, 10, 11, 99, 100, 101) or 7 test cases if we include 0.
• Note that we need to add more tests like alphabetic chars and special chars like %, *.

Practice 2
You have a password field that can contain up to 8 characters and must have at least 3 characters. What is the minimum number of test cases you will need in order to test the field? (Pay attention to the requirement that specifies the field's length and not what kind of chars it can get! In the real world we can't ignore it but in order to simplify the example we will ignore it).
Try to solve it and then continue to read the answer.

Practice 2 - answer
6 test cases: length 2, length 3, length 4, length 7, length 8, length 9 or 7 test cases Length 2, length 3, length 4, length 6, length 7, length 8, length 9. We can add a test case that test the empty string. 

Practice 3
You have a field that can contain up to 5 digits and can have 0 digits. The value of the field can be in the range of (-5148 to +3544) What is the minimum number of test cases you will need in order to test the field using "Boundary" testing?
Try to solve it and then continue to read the answer.

Practice 3 - answer

• For the length we have 5 test cases: 0 length, 1 length, 4 length, 5 length and 6 length.
• For the range we have 7 test cases: -5149, -5148, -5147, 0, +3543, +3544, +3545.
• Total of 12 tests cases.

we reduce the amount of test cases to be less then 12 (try to solve it and continue to read)?
Well, we can reduce it to 10 test cases by combine the value testing of the field with the length testing of the field.

Case #	Length	Value	Expected Result
1	0	None	Valid
2	1	0	Valid
3	4	3543	Valid
4	4	3544	Valid
5	4	3545	Invalid
6	5	-5149	Invalid
7	5	-5148	Valid
8	5	-5147	Valid
9	6	123456	Invalid
10	6	-45322	Invalid

This was an example of why you must use your head all the time, because sometimes you can combine methodologies with each other or combine them with your common sense and reduce the amount of testing or create smart tests that will reveal beautiful and important bugs.

Smoke , Sanity and difference between Sanity and regression testing.

Smoke Testing:-

1) Smoke testing basically known as the build verification testing.
2) Smoke testing is used to check the critical functionality working fine or not.
2) In smoke testing we check that the build is ready for the further testing or not.
3) Basically it is a tested by the developer, but in most of companies tester perform this task.
4) Smoke testing is used to avoid the time for the further testing.
5) If build pass the smoke test, then the build is ready for the further testing.

Example :- Supposes I have to test the  user dashboard, when I am logged in into the application blank page being displayed. So smoke test is fail and build should not be ready for the further testing.


 Sanity Testing:-

1) Sanity Testing is also a kind of build verification testing.
2) In sanity testing is performed to check that the bug have been fixed and no further issues are introduced due to these changes.
3) Sanity testing is perform by the testers.
4) Sanity testing is subset of Acceptance testing, it is also known as tester acceptance testing.

Difference Between Sanity and Regression Testing 

Sanity testing is basically the basic testing to accept the build for detailed testing.

Regression testing is testing the impact of changes after bug fix or after any change in the application or the environment.

Example:-  

Supposes I have edit profile page for the regression testing. But when I logged in into the application, blank page being displayed. Means no need to test the advanced testing because sanity is fail.  

Standard messages for Testing

Why standard messages document is needed ?

Currently we are not following any standardized format of messages in any of our projects.         

MESSAGES

					1.LOGIN
					1.	When the users tries to login without giving username & password	You must enter a valid Username & Password
					2.	When password is not given	You must enter a valid Password
					3.	When wrong user name is given & correct password	You must enter a valid Username & Password
					4.	When correct user name & wrong password is given
					5.	When both the user name & password are wrong
					2.CHANGE PASSWORD
					6.	When old password is incorrect	Please  check your old password
					7.	When old password is correct & new password & confirm password is not similar.	Passwords mismatch between new & confirm password. Please try again.
					8.	When no values are entered & submit button is clicked	Please enter old password & new password.
					9.	Enter old password & click submit  button without entering new password & confirm password	Please enter new password & confirm password
					10.	Enter New  password & confirm password, then Click on the submit button without entering old password	Please enter the old password.
					11.	If some special characters are not allowed, show the message just below the text box.	Please note that the special characters (specify the special characters) are not allowed.
					12.	If space is not allowed in password. Enter the password with space.	Please note that space is not allowed
					13.	If the number of characters chosen for password is less than the minimum length	Your password must contain at least ‘x’ characters.
					14.	If the number of characters chosen for password is more than the maximum length	You have exceeded the character limit
					3. FORGOT PASSWORD
					15.	In case of forgot password	Password reset instructions were sent to your e-mail address/The new password will be sent to your e-mail address
					16.	Without entering the email id(User Name) & click submit button	Please enter your Email Address below Password reset instructions were sent to your e-mail address/ The new password will be sent to your e-mail address
					17.	In case of email id ,enter an invalid mail id and click submit button	Please make sure that the e-mail id is entered correctly.
					4. REGISTRATION
					18.	If the user name already exists	Sorry, the username ‘abcd’ is already registered. Please try again.
					19.	If some special characters are not allowed, show the message just below the text box.	Please note that the special characters (specify the special characters) are not allowed.
					20.	Validation message if mandatory fields are not entered	Fields marked with an asterisk (*) are mandatory
					21.	If the number of characters chosen for Username/password is less than the minimum length	Must have at least ‘x’ characters. Your password /username  must contain at least ‘x’ characters.
					22.	If the number of characters chosen for Username/password is more than the maximum length	The value has exceeded the  maximum length Or Please note that only ‘x’ characters are allowed. Or You have exceeded the character limit
					23.	When space is not allowed in password	Please note that space is not allowed
					24.	If wrong image verification code is given	The characters you entered didn’t match the word verification. Please try again or The image verification code you entered is incorrect. Please try again
					25.	Suppose If there are multiple conditions like 5-15 chars are required & special characters except underscore are not allowed then the message should come as	Please note that the character limit is between 5 and 15. Special characters except underscore (_) are not allowed.
					26.	In case if age is given as a criterion for registration. For e.g.: Only a person who is 18 or above can register in a site. In such case validation is required	Sorry! You are not 18 yet. Registration failed!
					5. EMAIL
					27.	When no messages are available in any of the folders	The folders are empty.
					28.	After sending a message	Your message has been sent!
					29.	While composing, if email address is not valid	Please enter  a valid email address
					30.	Deleting messages from the folder	‘X’ message (s) deleted. Or   Message(s) deleted
					31.	Moving messages from 1 folder to another.	‘X’ message (s) moved to ‘Folder name’.
					32.	While deleting message/messages?	Are you sure you want to delete the selected item(s)?
					33.	If no items are selected and delete button is clicked	You must select at least one message. Please try again.
					34.	While deleting all items from a folder	Are you sure you want to permanently delete the selected item(s)?
					35.	When editing information in an email account	Your account information has been updated
					36.	If cancel button is clicked after entering edit page	Your account details have not been changed.
					37.	In case of email id ,enter an invalid mail id and click submit button	Login failed for user 'username'. You might have entered an incorrect username or password. Please try again.
					38.	If a message has to be sent to multiple persons and some of the ids entered are wrong	The email address (id) is not valid or Invalid email address.
					6. IMAGE GALLERY
					39.	Deleting an image	Are you sure you want to delete the selected image(s)?
					40.	When no images in an album	This album is empty
					41.	When there are no images in gallery	No image exists
					42.	If the uploaded image is of incorrect format (ex. A doc file’s extension is changed as .jpg) or  If other formats are uploaded	Please upload a valid Image type( Please note that only images with extension as .jpg, .gif, .png, .bmp etc) can be uploaded
					43.	If the size of images are large or less	Please note that images up to (specify the maximum length) only can be uploaded.
					44.	Same case with video files also.
					7. FILE UPLOADING
					45.	When uploading incorrect format or  If other formats are uploaded	Please upload a valid file. ( Please note that only files with (valid extensions) can be uploaded)
					46.	If the file size is large or less	Please note that files up to (specify the maximum length) only can be uploaded.
					8. SEARCH
					47.	If no results to display	Your search returned no results.
					48.	In search if searching has to be done using Ages or dates.	* Message should be according to the situation. Return date must occur after the depart date
					49.	When there are results to display after search, show a message on the top as	‘No. of results’ results found.
					50.	If pagination is available in search, and if 10 results are displayed on each page	Displaying 1-10 of 25 results of ‘search item’
					51.	With out entering an item and click on the search button	Please follow the criteria to search.
					9. BLOG
					52.	When publishing a blog	Your blog post has been published successfully
					53.	When posting a comment	Your comment has been posted.
					54.	When deleting a comment	The comment has been deleted.
					55.	When following a blog	You are now following ‘Blog name’.
					56.	Deleting a blog	Are you sure you want to delete the blog This will remove the associated comments
					57.	If the user has not posted any blog & if he clicks on ‘my blog’	You have not created any blog post yet.
					58.	If posting a blog from user side and will be displayed in user side only after approval of admin then	Thank you for posting your blog. It will be displayed only  after administrator's approval
					10. FORUMS
					59.	When posting a topic	Topic posted successfully
					60.	When posting a comment	Comment posted successfully
					61.	Deleting a forum topic	Are you sure you want to delete the ‘forum topic’ This will remove the associated comments
					62.	If posting a forum from user side and will be  displayed in user side only after approval of admin then	Thank you for posting your forum. It will be displayed only after administrator's approval
					63.	When deleting a comment	The comment has been deleted
					11. POLL
					64.	After casting votes.	Thank you for casting your vote
					65.	Next time if the user goes for polling	You have already voted in this poll
					12. COMMUNITY SITES
					66.	If  no result for  a user/community etc	Sorry we were not able to find the ‘user/community’ on ‘URL of the site’
					67.	If trying to post a new forum topic or trying to reply a particular topic without logging in.	Please log in to continue.
					68.	Suppose an account is activated only after getting an email from the admin & the user has to confirm by clicking that mail. If a user tries to add friends, communities, blog etc before that (e.g.  MySpace)	You can add friends/communities etc only after logging in. Please click on the confirmation link in the e-mail that you have received, to log in.
					69.	Suppose an account is activated only after getting an email from the admin & the user has to confirm by clicking that mail. If a user tries to login before confirming. (e.g. Face book)	You can log in only after following the steps given in the confirmation mail.
					70.	In case of forgot password	Enter your login email below. We will send you an email with a link to reset your password Password reset instructions were sent to your e-mail address/ The new password will be sent to your e-mail address
					71.	Joining a Group	Do you want to join ‘group name’?
					72.	Un join a group	Are you sure to un join from ’group name’?
					73.	In case of deactivating account	You can activate your account any time by logging in with your username & password.
					74.	Deleting an account	Deleting an account will permanently remove all your profile information (like friends, images, videos, blog etc).Do you wish to continue?
					75.	In case later if the user wants to re-register after deleting  & he has to start from the registration	Deleting an account will permanently remove all your profile information (like friends, images, videos, blog etc).
					76.	Privacy/notification setting changed	Privacy/ notification settings changed successfully.
						When there are no friends to display in friends list/category etc	Your friends list is empty.
					78.	When there are no categories for friends	You don’t have any categories for friends.
					79.	If message board/scrap book is empty	You don’t have any messages
					80.	After posting message in message board	Message posted successfully.
					81.	To block a user	Are you sure you want to block this user?
					82.	Unblocking a user	Are you sure you want to unblock this user?
					83.	Adding a user to friend’s list	Would you like to add ’username’ to your friend’s list?
					84.	Deleting a friend from friend’s list	Are you sure you want to delete ‘username’ from friend’s list?
					85.	Sending invitation to a friend	Would you like to invite ‘username’ to your friends list?
					13. NEWSLETTER
					86.	To subscribe for news letter	Do you wish to subscribe to the newsletter service?
					87.	Unsubscribe from newsletter	Are you sure you want to unsubscribe
					14. SPECIAL UPGRADE updates
					88.	Subscribe to special upgrades.	Would you like to subscribe to the special upgrade offers?
					89.	Unsubscribe special upgrade offers.	Are you sure you want to unsubscribe to the special upgrade offers?
					15. GENERAL MESSAGES
					90.	When deleting an item/items	Are you sure you want to delete the selected item(s)?
					91.	When editing an item Details.	Details updated & saved successfully.
					92.	When adding an item.(User, User details, Image, Video etc)	“Item(s)” added successfully.
					93.	Dependency message: IF B is dependent on A & if A’s deletion deletes B also	Deleting A also results in deletion Of B. Are you sure you want to delete?
					94.	Dependency message: If B is dependent on A & A can be deleted only if B is deleted	A cannot be deleted now. Please delete B first & then delete A.
					95	If administrator’s approval is required for completing a user registration	Thanks for registering. You will get a confirmation mail soon. You can log in only after following the steps given in the confirmation mail.
					95.	If posting any comments in any site & that has to be validated by admin	Thanks for your comments. Your comments will be available only after administrator's approval
					16. SUCCESS MESSAGES
					96.	Password change	Your password has been changed
					97.	Registration success	You have successfully registered (in case of job sites, matrimonial, exams).  Thank you for your interest in ……………..  or Congrats! Your registration is complete now.
					98.	After registration in a community	Congrats! You are now a member of ‘Community name’.
					99.	After making a payment	Payment has been successfully made
					100.	After adding  ‘X’	‘X’ added successfully
					101.	After editing ‘X’	‘X’ updated successfully.

References

1.      www.google.com 

2.      www.yahoo.com  

3.    www.aol.com

4.    www.facebook.com

5.    www.mysapce.com

6.    www.blogger.com

7.    www.rediff.com

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ISPG QA DEPT DOCUMENTS