How to Test Stored Procedures in SQL Server

It is essential to test stored procedures in SQL Server to know stored procedures’ functionality, performance, and accuracy while handling data processing tasks.

In this SQL Server tutorial, I will explain different approaches for testing stored procedures and why it is important to test the stored procedure.

Also, you will understand how to perform unit and error-handling testing.

Table of Contents

Test Stored Procedures in SQL Server

To test stored procedures in SQL Server, there are different approaches that you can choose. But before that, you need to know why testing is essential.

As you know, stored procedure contains reusable code, which can be used many times at different places as the requirement arises; this code is logic that performs specific tasks within a database.

Testing them precisely helps identify and prevent issues like data inconsistencies, security vulnerabilities, logic errors, etc.

Also, for specific errors, you can implement error handling,

Next, to test the stored procedure, there are different strategies. To test the stored procedure ineffectively, you can use the following strategies:

Unit Testing: In this kind of testing, individual stored procedures are tested independently or in isolation to check their functionality against expected inputs and outputs.
Integration Testing: Here, stored procedures are validated for interactions between procedure and database objects like views, tables, or functions to ensure seamless integration within the database ecosystem.
Performance Testing: Stored procedure performances are evaluated under different loads and values to identify and address performance issues.
Data Consistency Testing: Stored procedures are verified to maintain data consistency by comparing expected results with actual database states after execution.
Error Handling Testing: This testing tests the error handling strategies in the stored procedure by simulating error scenarios and validating error messages and recovery processes.

Let’s take an example: There is a table for Employees with columns for EmployeeID, Name, Salary, and Department, which is shown below.

Test Stored Procedures in SQL Server Employees Table

Now, create a store procedure that will update the employee information. To create a stored procedure, run the command below in your query editor.

CREATE PROCEDURE UpdateEmployeeDetails
	@EmployeeID INT,
	@NewName NVARCHAR(50),
	@NewSalary DECIMAL(10,2),
	@NewDepartment NVARCHAR(50)
AS
BEGIN
	UPDATE Employees
	SET Name = @NewName,
	    Salary = @NewSalary,
    	Department = @NewDepartment
	WHERE EmployeeID = @EmployeeID;
END;

To test this stored procedure, whether it is working or not, let’s say that you want to update the department of employees with an ID equal to 4 and the salary.

Execute the stored procedure with the following test data: EmployeeID = 4, NewName=’Emily Brown’, @NewSalary=90000, @NewDepartment=Marketing.

EXECUTE UpdateEmployeeDetails @EmployeeID =4 ,@NewName ='Emily Brown', @NewSalary=90000, @NewDepartment='Marketing';

When you test the UpdateEmployeeDetails store procedure with input data, it correctly updates the employee with a new salary and department.

The employee with ID 4 has a salary of 90000, and the department is Marketing. This one is unit testing.

You can also perform performance testing by measuring the execution time of the stored procedure with large data in the database to ensure acceptable performance.

Also, Error handling testing, for example, attempts to update a non-existent employee and validate error messages and rollback behaviour.

Next, let’s see Error handling testing.

Error Handling Testing of Stored Procedure

Here, I will show you how to implement error handling when updating an employee’s details with invalid input values and ensure that data integrity is preserved through proper error handling and rollback mechanisms.

Let’s update the UpdateEmployeeDetails store procedure with an error handling mechanism and test it when invalid input values are provided for the employee’s name, salary, or department.

I would suggest you delete the previous stored procedure or update it. Use the below command to update or create a new stored procedure with error-handling mechanisms.

CREATE PROCEDURE UpdateEmployeeDetails
	@EmployeeID INT,
	@NewName NVARCHAR(50),
	@NewSalary DECIMAL(10,2),
	@NewDepartment NVARCHAR(50)
AS
BEGIN
	BEGIN TRY
    	BEGIN TRANSACTION;
   	 
    	-- Check if the employee exists
    	IF NOT EXISTS (SELECT 1 FROM Employees WHERE EmployeeID = @EmployeeID)
    	BEGIN
        	RAISERROR('Employee not found.', 16, 1);
        	ROLLBACK TRANSACTION;
        	RETURN;
    	END
   	 
    	-- Update employee details
    	UPDATE Employees
    	SET Name = @NewName,
        	Salary = @NewSalary,
        	Department = @NewDepartment
    	WHERE EmployeeID = @EmployeeID;

    	COMMIT TRANSACTION;
	END TRY
	BEGIN CATCH
    	IF @@TRANCOUNT > 0
        	ROLLBACK TRANSACTION;
   	 
    	THROW;
	END CATCH;
END;

Look at the above code very closely and see how the testing mechanism is implemented, and while varying this testing mechanism, see where you can make improvements based on your different input values.

Test it with invalid input after creating an UpdateEmployeeDetails stored procedure with an error handling mechanism.

Make sure your table contains test data with employees containing a known EmployeeID.

Run the stored procedure with an invalid input value for the employee’s name, salary, or department.

EXEC UpdateEmployeeDetails
	@EmployeeID = 21, -- Invalid EmployeeID
	@NewName = '', -- Empty name
	@NewSalary = -500, -- Negative salary
	@NewDepartment = 'Invalid Department'; -- Invalid department name

Error Handling Testing of Stored Procedure

As you can see, the error handling mechanism works because when an invalid EmployeeID (21) is provided, it shows the error ‘Employee not found’.

You must verify a few things for error handling: always validate that the stored procedure should raise the right error for each invalid input value.
Also, ensure no changes are made to the database, confirming the rollback behaviour. The error message should tell that a specific invalid input is causing the error.

This is how to perform error handling testing of stored procedures in SQL Server.

You can also perform integration testing and performance testing in the same way.

Conclusion

You learned how to test stored procedures in SQL Server and how testing is significant. Additionally, you learned different testing strategies that you can implement.

Finally, you learned how to do unit and error-handling testing of stored procedures.