Nobody wants to be known for their mistakes and their negligence, and same is the case with the Testers. When the Testers are assigned an application to test, then from that moment, they take the responsibility and the application also acts as a platform to show their practical and technical testing knowledge.

So, to describe it technically, to ensure that testing is done completely, it is necessary to perform “End to End testing”.

In this article, we will learn what is End to End Testing, how it’s done, why it’s necessary, what are the matrices used, how to create an end to end specific test cases and some few other important aspects also. We will also learn about System testing and compare it with End to End testing.

What is “End to End Testing”?

Term “End to End testing” is defined as a testing method which determines whether the performance of an application is as per the requirement or not. It is performed from start to finish under real-world scenarios like communication of the application with hardware, network, database, and other applications.

The main reason for carrying out this testing is to determine various dependencies of an application as well as ensuring that accurate information is communicated between various system components. It is usually performed after the completion of functional and system testing of any application.

Let us take an example of Gmail:

• End to End testing of a Gmail account will include the following steps:
• Launching the Gmail login page through URL.
• Logging into Gmail account by using valid credentials.
• Accessing Inbox. Opening Read and Unread emails.
• Composing a new email, reply or forward an email.
• Opening Sent items and checking emails.
• Checking emails in the Spam folder
• Logging out of Gmail application by clicking ‘logout’

How does it work?

To understand a bit more, let us find out How it works?

Take an example of Banking Industry. Few of us must have tried out Stocks. When a Demat account holder, purchases any share, a particular percentage of an amount is to be given to the broker. When the shareholder sells that share, whether he gets profit or loss, a particular percentage of the amount is then again given to the broker. All these transactions are reflected and managed in accounts. The whole process involves Risk Management.

When we look at the above example, keeping the End-to-End test in mind, we will find that the whole process includes multiple numbers as well as different levels of transactions. The whole process involves many systems that can be difficult to test.

There are 2 different methods

Horizontal End to End testing:
This method is used very commonly. It occurs horizontally across context of multiple applications. This method can easily occur in a single ERP (Enterprise Resource Planning) application. Take an example of a web-based application of an online ordering system. The whole process will include accounts, inventory status of the products as well as shipping details.

Vertical End to End testing:
In this method, all the transactions of any application are verified and evaluated right from the start to finish. Each individual layer of the application is tested starting from top to bottom. Take an example of a web-based application that Uses HTML codes for reaching web servers. In such cases, API is required to generate SQL codes against the database. All these complex computing scenarios will require proper validation and dedicated testing. Thus this method is much more difficult.

‘White Box testing’ as well as ‘Black Box testing’ both are associated with an end to End testing. Or in other words, we can say, this is the combination of benefits of both white box testing and black box testing. Depending on the type of software being developed, at different levels, both the testing techniques i.e. white box and black box testing are used as and when required. Basically, End to End test performs functional as well as the architectural approach for any software or programs to validate system functions.

Testers, like End to End testing, because writing test cases from user’s perspective and in a real-world scenario, can avoid the two common mistakes .i.e. ‘missing a bug’ and ‘writing test cases that do not verify real-world scenarios’. This provides testers, an immense sense of accomplishment.

Below enlisted are few guidelines that should be kept in mind while designing the test cases for performing this type of testing:

• Test cases should be designed from the end user’s perspective.
• Should focus on testing some existing features of the system.
• Multiple scenarios should be considered for creating multiple test cases.
• Different sets of test cases should be created to focus on multiple scenarios of the system.

As we execute any test cases, similar is the case with this testing. If the test cases are ‘Pass’ i.e. we get the expected output, it is said that the system has successfully passed End to End test. Likewise, if the system does not produce the desired output, then a retest of a test case is required keeping in mind the areas of failure.

Why we perform End to End Testing?

In the present scenario, as also shown in the diagram above, a modern software system comprises of its interconnection with multiple sub-systems. This has made modern software systems as a very complicated one. These sub-systems we are talking about can be within the same organization or in many cases can be of different organizations also. Also, these sub-systems can be somewhat similar or different from the current system. As a result, if there is any failure or fault in any sub-system, it can adversely affect the whole Software system leading to its collapse.
These major risks can be avoided and can be controlled by this type of testing:

• Keep a check and perform system flow verification.
• Increase the test coverage areas of all the subsystems involved with the software system.
• Detects issues, if any with the subsystems and thus increase the productivity of the whole software system.

Below mentioned are the few activities that are included in the end to end process:

• A thorough study of requirements to perform this testing.
• Proper set up of test environments.
• A thorough study of Hardware and Software requirements.
• Descriptions of all subsystems as well as main software system involved.
• Enlist the roles and responsibilities for all the systems and subsystems involved.
• Testing methods used under this testing as well as standards that are followed, its description.
• Test cases designing as well as tracing requirement matrix.
• Record or save the input and output data for each system.

We will look into all the 3 categories one by one:

User Functions:

Following actions should be performed as a part of building User Functions:

• Listing features of the software systems and their interconnected sub-systems.
• For any function, keep track of the actions performed as well as Input and Output data.
• Find the relations, if any between different Users functions.
• Find out the nature of different user functions .i.e. if they are independent or are reusable.

Conditions:

Following activities should be performed as a part of building conditions based on user functions:

• For each and every user functions, a set of conditions should be prepared.
• Timing, Data conditions and other factors that affect user functions can be considered as parameters.

Test Cases:

Following factors should be considered for building test cases:

• For every scenario, one or more test cases should be created to test each and every functionality of the user functions.
• Every single condition should be enlisted as a separate test case.

Metrics involved:

Moving to the next important activities or metrics involved in this testing:

1. Status of Test case preparation: This can be tracked in the form of a graph to represent the progress of the planned test cases that are under preparation.
2. Weekly tracking of Test progress: This includes week wise representation of the test cases execution progress. It can be reflected through percentage representation for a pass, fail, executed, not executed, invalid, etc cases.
3. Status and detailed report for Defects: Status report should be prepared on a daily basis to show the test case execution status as well as defects found and logged as per their severity. Weekly, the percentage of the open and closed defects should be calculated. Also, based on defect severity and priority, defects status should be tracked on a weekly basis.
4. Test environment available for performing End to End testing: This keeps a track of the test environment time duration allotted as well as the test environment time actually used while performing End to End testing.

We have almost seen all aspects of this testing. Now let us differentiate “System Testing” and “End to End testing”. But before that let me give you a basic idea of “System testing” so that we can easily differentiate between the two forms of software testing.

System testing is the form of testing which includes a series of different tests whose purpose is to perform the complete test of the integrated system. System testing is basically a form of black box testing where the focus is on the external working of the software systems from the user’s point of view keeping real-world conditions as consideration.

System testing involves:

• Testing a fully integrated application including the main system.
• Determine the components interact with one another and within the system.
• Verify the desired output on the basis of the input provided.
• Analyzing the user’s experience while using various aspects of the application.

Above we have seen the basic description of System testing to understand it. Now, we will look out the differences between “System Testing” and “End to End testing”.

S.No.	End to End Testing	System Testing
1	Validates both the main Software system as well as all the interconnected Sub-Systems.	As per the specifications provided in the Requirement document, it just validates the software system.
2	The main emphasis is on verifying the end to end testing process flow.	The main emphasis is on verifying and checking features and functionalities of the software system.
3	While performing testing, all the interfaces including the backend processes of the software system are taken under consideration.	While performing testing, only the functional and the non- functional areas and their features are considered for testing.
4	End to End testing is executed /performed after the completion of System testing of any software system.	System testing is basically performed after the completion of integration testing of the software system.
5	Manual testing is mostly preferred for performing end to End testing as these form of testing involves testing of external interfaces also which can be very difficult to automate at times. And will make the whole process very complex.	Both manual and automation testing can be performed as a part of System testing.

Conclusion:

After understanding the various aspects of End to End testing, its processes, metrics, etc. And also differentiating between System testing and End to End testing, we can conclude as below:

For any commercial release of the software, End to End testing plays an important role as it tests the entire application in an environment that exactly imitates real world users like network communication, database interaction, etc.

Mostly, the end to End test is performed manually as the cost of automating such test cases is too high to be afforded by every organization. This is not only beneficial for system validation but can be also considered useful for testing external integration.