How to write Test Cases?

In Manual Testing, Testers will test the Application  by executing the Test cases manually  without requiring  any automation tools.  Manual testing will take significant time to cover all the requirements. So, it is very important to write test cases effectively to cover all the requirements while keeping number of test cases at  minimum level.  Let us  see how to write test cases  for testing an application.

What is  Test Case ?

Test case is “Documentation specifying inputs, predicted results, and a set of execution conditions for a test item.” The  purpose of Test Case  is to divide the software function into small units of function that is testable with input, and producing result that is measurable.

i-e  A test case is a feature/function description that should be executed with a range of input, given certain preconditions, and the outcome measured against expected result.

These are the  fields commonly present in the Test Cases :

  • Test case id
  • Test Case Description
  • Procedure / Test Steps
  • Test data
  • Expected result
  • Actual result
  • Status ( Pass/ Fail)
  • Comments

Test cases should be simple and easy to understand for Developers.

Test Case ID :

This ID should be Unique throughout the Testing Application and not to change at any moment.

Test Case Description:

Explain the function under test. Clearly state exactly what attribute is under test and under what condition.

Prerequisites– Every test needs to follow a sequence of actions, which lead to the function under test. It could be a certain page that a user needs to be on, or certain data that should be in the system . For example  registration step should be completed before start testing login.

Procedure/Steps:

Sequence of steps to execute the specific function.

Test data:

Specify the data used for a particular test or if it is a lot of data, mention the path of a file where this data is stored.

Expected Result:

Clearly specify the expected outcome in terms of the page/ screen that should appear after the test, changes that should happen to other pages, and if possible, changes that should happen to the database..

Actual Result :

State the actual result of the function execution. Especially in case the test case fails, the information under ‘actual result’ will be very useful to the developer to analyse the cause of the defect.

Comments:

In this section you can add your reviews, suggestions and ideas to developers for the bug how we fix that.  Especially this section made to communicate with developers.

Test case writing procedure

  • Get as much information about the application as possible through available documentation (requirement specs, use cases, user guides) , tutorials, or by exercising the software itself (when available)
  • Determine a list of features and different user roles.

 

Say for example, if you are writing Test Cases for testing  this Timesheet Application.

First you should understand the features available in this timesheet application by reading the help files and other available documents about this timesheet application.

You should know about different user roles (e.g user, admin) involved in this application.

Once you gather all the details about this application, you can start writing test cases. Find below one sample, and you can show/test your test case writing skills by adding more test cases thro’ the comments section.

  • Test case id – LG01 (LG refer as Log In)
  • Test Case Description -Check Case sensitivity in  Log In Functionality
  • Procedure
  1. Load login screen by visiting http://qualitypointtech.net/timesheetdemo/index.php
  2. Enter valid username and password in Upper case.
  3. Click “Login button”
  • Test data – Username as user || Password as USER
  • Expected result – Alert box like CAPS LOCK on to warn the user
  • Actual result – But its not visible and accessing with uppercase letters.
  • Status ( Pass/ Fail) – Fail
  • Comments –  Password is an user’s choice so we can’t restrict so we have to give the warn or alert box or format that password should be like this.
Like wise, for each and every action we have to write test cases.

At the time crunch of any project, the testers simply go with the Adhoc Testing and Exploratory testing.

 

Writing Good Test Cases and Finding Bugs effectively

To develop bug free software application, writing good test cases is essential.Here, we will see how to write good test cases.
Before seeing this, we should understand what is Good Test Case.There won’t be any solid definition for “Good Test Case”.

I will consider a Test Case as “Good” only when a Tester feels happy to follow the steps in the Test Case which is written by another Tester.Test Cases will be useful only if they are used by the people.

If a test case is poorly written with excessive unwanted steps, then most of the Testers won’t read it fully. Just they will read few lines and will execute it based on their own understanding which will be mostly wrong.On the other hand, if it is having fewer details then it is difficult to execute it.

As of now, I am thinking below things for writing effective Test Cases.

  • Before start writing test cases, become familiar with the (AUT) Application Under Test. You will become familiar with Application by doing some adhoc/exploratory testing.
  • We should read the requirements clearly and completely. If we have any questions in the Requirements it should be clarified by appropriate person (e.g Customer or Business Team). And also, it is good practice to gather some basic domain knowledge before getting into reading requirements and writing Test Cases. And also, we can have discussion/meeting with developers/business team
  • Very Important thing is, we should use only simple language or style to write the Test cases so that any one can easily understand without any ambiguity
  • Give meaningful and easily understandable Test case ID/number.
    For example, if you are writing Test case for testing Login module you can Test Case ID as below.1a – for testing positive scenario such as entering valid username and valid password.
    1b – for testing negative scenario such as entering invalid username and invalid password.By giving Test Case number as above instead of giving sequential number, we can easily add any new case such as below one without needing to adjust/modify number of any other subsequent test cases.1c- for testing negative scenario such as entering valid username and invalid password.
  • And also, if we have any similar module we can give separate sequence number for specifying the module.For example, assume that we are having separate login modules for User and Admin with little changes.
    In this case we can give number as below,
    1.1-First case in User module.
    1.2-Second case in User module.
    2.1-First case in Admin module
    2.2-Second case in Admin module.If Test Description/Steps/Expected Results of 2.1 is mostly same as 1.1 then we should refer 1.1 in 2.1 instead writing the sample details again.By doing like this, we can avoid redundant details to have clear test case document.
  • Test Description should be short and it should uniquely represent the current test scenario without any ambiguity.
  • In any situation, don’t use “if condition” in the Test steps. Always address only one scenario in one test case. It will be helpful to have unambiguous Expected Result.
  • Give some sample test data that will be useful for executing the test cases.
  • If the Test Case requires any Preconditions/prerequisite don’t forget to mention them.
    The best way is, we should arrange/order the Test Cases such that the need for specifying precondition is minimum.For example, we need to write test case for testing user creation, user modification and user deletion.For doing user modification and user deletion we should have already created user as precondition.If we arrange the Test cases in below mentioned order, we can avoid the need for specifying any preconditions/prerequisites.
    1-Test case for creating user.
    2-Test case for verifying duplicate/existing user when adding another user with same username.
    3-Test case for modifying user.
    4-Test case for deleting user.
  • Keep Traceability Matrix to make sure that we have written test cases for covering all requirements.
  • Once after completing all positive scenarios, think about all possibilities of negative scenarios to have test cases which will effectively find most of the bugs.For doing this we can refer alternate flow section of use case document, and we can think about different data, boundary conditions, different navigations paths and multi user environment.
  • In the test case document, we can give link to screenshots explaining the steps and/or expected results with pictures. But anyway, it is not good practice to place the screenshots within the Test Case document itself unless it is very essential
  • Many tools are available to capture the screenshots with user action as video. We can make use of them to keep video explaining the steps and expected results clearly in case the test case requires any complex steps. We can give link to this video from the test case document.