Read Part 1 of this series here: How to do Unit Test using NUnit : Part 1
The last article explained how to start with Unit Testing using NUnit. In this article I will discuss the following two topics:
- Test Setup
- Test Teardown
You need Test Setup and Test Teardown to remove any dependency between tests. Assume a scenario that you want to:
- Create an instance of a specific object before execution of any test
- Delete a specific file from the file system before execution of any test
- Insert some test data or create some test data before execution of any test
- and so on
In the above stated scenario you may want to create a Test Setup. A Test Setup is a piece of code executed before execution of any test.
![UnitTesting1.jpg]()
Another use case could be that you want to perform a specific task after execution of each test. So once a test is executed a certain task should be done and we call that a Test Teardown. There could be a scenario that you want to:
- Destruct an instance after execution of any test
- Remove test data after execution of any test
- Delete a file from the file system after execution of any test
- and so on.
In the above scenario you may want to create a Test Teardown. A Test Teardown is a piece of code executed after execution of a test.
![UnitTesting2.jpg]()
In NUnit you can create a Test Setup and a Test Teardown by using [Setup] and [TearDown] attributes on a function.
So a Test Setup can be created as in the following:
![UnitTesting3.jpg]()
And you can create a Test Teardown as in the following:
![UnitTesting4.jpg]()
If there are 5 tests in your test class then these two functions will be executed 5 times. Now let us put our explanation into a concrete example. Assume that you are writing a Unit Test for a Product class. The Product class is defined as in the following:
namespace MyAppToTest
{
public class Product
{
double productPrice;
public double ProductPrice
{
get
{
return productPrice;
}
set
{
productPrice = value;
}
}
}
}
A Unit Test is written to test the validity of the product price as in the following:
[Test]
public void IsValidProductPrice()
{
p.ProductPrice = 100;
if (p.ProductPrice > 0)
{
result = true;
}
Assert.IsTrue(result, "Product Price is valid");
}
You can write a Test SetUp and TearDown as in the following:
Product p;
bool result;
[SetUp]
public void TestSetup()
{
p = new Product();
result = false;
}
[TearDown]
public void TestTearDown()
{
p = null;
result = false;
}
The preceding two functions will be executed each time before execution of each test and after execution of each test. In writing a Unit Test, Test SetUp and Test TearDown are very handy and useful.
I hope you find this article useful. Thanks for reading.
Further Readings