Unit testing in SQL Server, taking a first look a tSQLt

This is the third post in my Unit Testing series, today we are looking at what tSQLt, in the next post we will take a look at how to install tSQLt

What is tSQLt?  Here is how it is described on the tSQLt website


tSQLt is a database unit testing framework for Microsoft SQL Server. tSQLt is compatible with SQL Server 2005 (service pack 2 required) and above on all editions.

Main features

tSQLt allows you to implement unit tests in T-SQL. This is important as you do not have to switch between various tools to create your code and your unit tests. tSQLt also provides the following features to make it easier to create and manage unit tests:

• Tests are automatically run within transactions – this keeps tests independent and reduces any cleanup work you need
• Tests can be grouped together within a schema – allowing you to organize your tests and use common setup methods
• Output can be generated in plain text or XML – making it easier to integrate with a continuous integration tool
• Provides the ability to fake tables and views, and to create stored procedure spies – allowing you to isolate the code which you are testing

So basically after you install tSQLt on your SQL Server instance, it is just a database, you now have a unit test framework that you can use. They way you use tSQLt is by creating stored procedures that will do the unit testing for you. It all runs within SQL Server.

You can run 1 test, all tests in a test class or all tests for all test classes by calling a single stored procedure.  Here are the Assertions and Expectations that ship with tSQLt

Assertions

AssertEmptyTable

AssertEquals

AssertEqualsString

AssertEqualsTable

AssertLike

AssertNotEquals

AssertObjectDoesNotExist

AssertObjectExists

AssertResultSetsHaveSameMetaData

Fail

Expectations

ExpectException

ExpectNoException

In addition to that you can of course use IF EXISTS..... and then a Fail Assertions to test anything that is not testable with the built in Assertions 

In addition to be able to run this all from a query window in SSMS, if you have Red Gates SQL Test then you can use that to run the tests, you will get a graphical indicator at that point. If the test passes it will be green, if it fails it will be red.

In the next post, we will take a look at how to install tSQLt on your database instance and write our  first test.