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Unit testing? No need
1. Lets write a Math Calculator class.
We know it will work because we have 'enough' confidence on it.
Unit testing? No need
2. Lets write a Regular Expression generator class.
Generate Only Alpha Allowed expression with different length
Generate Only Alpha & Numeric Allowed expression with different length
Do you know your code will work before you test by yourself?
If you want to know whether your code is working or not, how would you test?
Create an User Interface Project? then
Put some input fields? then
Put an event trigger control (like button etc)? then
Call your regex method from this project UI?
You would do that.. won't you?
Any other idea?
If I say you to put your code under a testing machine. You don't need to test by
yourself using the UI, would you mind?
Lets see one of the most common testing tool of the world.
Anyone wouldn't dare to test that by his/her finger to calculate the result.
Or would anyone?
Why would you need that?
Because you don't need to manually input the values each of the time you want
Because you don't need to input different values each of the time you want to
Because you don't need to click and press keyboards each of the time you
want to test
Because after you modify some of your classes you don't want to test manually
the rest other classes
And many more because left...
Who says to write unit test?
"Any program feature without an automated test simply doesn't exist"
I Don't know those guys
I have enough skill to write codes which act what I expect that to do..
I don't want to write Test Code because I am a
"Super Geek Alien Type Genius Programmer, Not a Tester"
Probably you know these
Microsoft ASP.NET Razor 2
You will be unusual if you don’t write test code for your production code.
Visual Studio 2012
Sql Server (any)
Lets test our Add method
public class MathCalculator
public int Add(int first, int second)
return first + second;
public class MathCalculatorFixture
public void TestAddReturnsSum()
MathCalculator calculator=new MathCalculator();
int result = calculator.Add(10, 20);
Criteria of GOOD Unit
Each of your test should focus on a single behaviour of a single method.
So it should be
Manual testing is superb !!!
What would you do if you don't have any unit testing framework to test the
Add() method we wrote just now?
Automated VS Manual Testing
Manual Tests is more expensive and time consuming
Manual Testing becomes mundane and boring
Automated Tests are reusable
Manual Tests provide limited Visibility and have to be repeated by all
Automated Tests can have varying scopes and may require less complex setup
Automated Testing ensures repeatability (missing out)
Automated Testing drives cleaner design
Automated Tests provide a Safety Net for Refactoring
Automated Tests are living up-to-date speciﬁcation document
Automated Tests dose not clutter your code/console/logs
What the Guru's are
“Any program feature without an automated test simply doesn’t exist.”
from Extreme Programming Explained, Kent Beck
We want to check that whether the username of the student object has
minimum 6 characters in length.
Lets test it.
public class StudentManager
public bool IsAllowedToProceed(string userName)
Steps we should follow
Prepare the objects and appropriate data
Call the appropriate method
Assert the expected values with the actual values
What should we focus?
One test method should focus on a single behaviour of the method to be
If a single method can behave multiple ways, we should write different test
methods to test each of the expected scenarios.
Discussion and change of the requirements according to the audience level.
1. Create different criteria for a username to have and test those criteria
Another Example scenario
A user can attempt to login 3 times sequentially. On failing the 3rd time, his
account will be locked. On the 4th time, his account can't be accessed
whether he gives valid credentials or not. After an hour he will be again able
to try to login.
Find out the possible criteria to test the scenario.
Possible scenarios to test
So, the possible scenarios might be
1. Ideal case, where user inputs are valid and he will be given pass to proceed
2. Worst case, using invalid password, the user will try login 3 times in a
sequence and in the 4th time he will receive a account lock notification
3. User can not proceed to the next step if he inputs 3 times in a row, but in the
4th time he use the valid password because the system is locked
4. After one hour user can access the system and the counter is 1
5. After one hour blocking time user can login into the system with valid
password on the 4th time
Test Method is explaining
and if required we would add more..
Now Lets discuss about the
Unbearable Test Code
Don’t copy and paste
Don’t Repeat your code
Know your fixture
Don’t be optimistic
Be clear about the Unit Test Coverage
Know your Testing Framework
Don’t test everything at a time (image in next page)
Avoid inappropriate dependencies of your test method
Try: One Assertion per test
At least One concept per test
Appropriate error message
Designing Effective Micro
Do the Black-box testing with your class. Avoid white-box testing.
A good unit test
Express intent, not implementation details
Small and Simple: Easy to quickly comprehend
Run fast (they have short setups, run times, and break downs)
Run in isolation (reordering possible)
Run in parallel
Use data that makes them easy to read and to understand
Frequently Run with every code change
Test is not unit test if
Has External Dependencies
It talks to the Database
It communicates across the Network
It touches the File System
You have to do special things to your Environment – (such as editing conﬁg
ﬁles) to run it
It can't run at the same time as any of your other unit tests
Order Dependencies - Only works when run in certain order
Do we need to follow all of
those to write unit test?
Sometimes we tweak !!!
At least we can tweak according to our need instead of not writing them at all
So what we are tweaking
while testing Database
public void TestGetShouldReturnUser()
using (TransactionScope scope=new TransactionScope())
IUserRepository repository = new UserRepository(new
User user = CreateUser();
User returnedUser = repository.Get(user.Id);
Unit testing Advanced
Lets talk about the other attributes
How to write the test when our production code throws exceptions?
Practice (Sales tax)
Sales Tax Introduction
Basic sales tax is applicable at a rate of 10% on all goods, except books, food,
and medical products that are exempt.
Import duty is an additional sales tax applicable on all imported goods at a rate
of 5%, with no exemptions.
When I purchase items I receive a receipt, whichlists the name of all the items
and their price (including tax), finishing
with the total cost of the items, and the total amounts of sales taxes paid. The
rounding rules for sales tax are that for
a tax rate of n%, a shelf price of p contains (np/100 rounded up to the nearest
0.05) amount of sales tax.
Write an application that prints out the receipt details for these shopping
Practice (Sales tax)
1 book at 12.49
1 music CD at 14.99
1 chocolate bar at 0.85
1 book : 12.49
1 music CD: 16.49
1 chocolate bar: 0.85
Sales Taxes: 1.50
1 imported box of chocolates at 10.00
1 imported bottle of perfume at 47.50
1 imported box of chocolates: 10.50
1 imported bottle of perfume: 54.65
Sales Taxes: 7.65
Practice (Sales tax)
1 imported bottle of perfume at 27.99
1 bottle of perfume at 18.99
1 packet of headache pills at 9.75
1 box of imported chocolates at 11.25
1 imported bottle of perfume: 32.19
1 bottle of perfume: 20.89
1 packet of headache pills: 9.75
1 imported box of chocolates: 11.85
Sales Taxes: 6.70