Manual Testing Vs Automated Testing - Key Differences


Manual Testing and Automated Testing are different in various aspects with their own set of pros and cons. And knowing these differences goes a long way to testing a system successfully.

After all, you may need to use one or both during the testing process.

So, in this article we will dive deep into the differences between manual and automation testing to give you a rundown of some important differences between the two. 

Manual Testing vs Automated Testing — Overview

Manual and Automated testing differ in their style of execution.

In manual testing, test cases are executed manually. On the other hand, Automation testing refers to test cases being executed by test scripts.

So, manual testing requires a human to execute test cases while scripts execute the test cases in the case of automation testing.

Manual Testers define test cases based on requirements, specifications, and user experience considerations. Test cases describe expected behavior for various scenarios and expected outcomes.

Automation engineers write test scripts in programming languages to mimic user interactions and verify system behavior. Frameworks and libraries like Selenium and Cypress assist in script development and maintenance.

In the case of interaction, manual testers interact with the system step-by-step, following pre-defined test cases. They record observations and identify deviations from expected outcomes.

On the other hand, scripts are executed automatically by automation tools, and they simulate user actions and capturing system responses. Tools perform automated comparisons with expected results and raise flags for discrepancies.

Manual Testers document test results as reports, often using spreadsheets or dedicated bug tracking systems. Reports typically include steps to reproduce issues, screenshots, and severity assessments.

Automation Tools automatically generate reports summarizing test results, pass/fail rates, and detailed logs of execution.

These reports often integrate with continuous integration/continuous delivery (CI/CD) pipelines for feedback and analysis.

Manual Testing vs Automated Testing — Head-To-Head Comparison

We can differentiate between Manual and Automated Testing in the following 5 aspects:

1. Execution Speed

Running tests on software can be quite tedious. There are tons of scenarios you need to consider with many inputs.

Testing all the inputs and scenarios one-by-one manually is too much of a hassle. So, automation testing is much better in terms of execution speed. 

You can run many tests concurrently at lightning speeds with Automation script.

2. Reliability

The chances of making mistakes while performing mundane tests is high. But running mundane tasks via automated scripts produces more reliable results.

So, automated testing is a bit more reliable in the case of test scenarios requiring a high number of iterations of inputs.

But manual testing proves to be more reliable when you need to test intangible aspects of a software such as the quality of user experience and where critical thinking and logic is paramount.

3. Documentation

You need to write, edit, and finalize documents on your own with manual testing but when it comes to automation testing, documentation and authoring is automatic. You can save screenshots of bugs and create reports with reporting tools.

4. Ease of Execution

Manual testing is easy to execute. You don’t need to setup environments and write code to test software manually. So, the barrier to entry is also low.

But in the case of automation testing, we need to learn a language, write scripts and run it on test environments. 

5. Use Cases

Manual Testing is great when used for exploring a system, to test a system more flexibly, and to handle complex situations.

Automation testing, on the other hand, makes it easy to test scenarios where you need to test for many inputs.

Let’s recap the differences.


Advantages of Manual Testing Over Automation Testing

In manual testing, a tester can adjust their testing approach at any time to explore unexpected scenarios. They can also delve deeper into emerging issues and adapt to changes in the future.

This is crucial for identifying edge cases and hidden defects that automation might miss.

Manual Testers can use their critical thinking, intuition, and understanding of user behavior to find issues that would require complex scripting or data manipulation for automation. They can also assess usability, aesthetics, and other subjective aspects that machines struggle with.

In addition to this, the importance of experience can never be overlooked. A manual tester with experience can judge the expected outcomes and bug seriousness in similar projects, which can be helpful in a holistic testing approach.

When you are focused on finding new issues and understanding the system, manual testing is a much better option. It allows for quicker exploration and improvisation compared to setting up and executing automated scripts.

Automation tools and training can be expensive, especially for small projects or teams with limited budgets. Manual testing offers a more cost-effective option for such scenarios.

Human eyes are adept at spotting visual inconsistencies, layout issues, and other UI/UX glitches that automation scripts might not be able to define or capture effectively.

Testers can directly experience the user interface, evaluate ease of use, and provide valuable feedback on intuitiveness, workflow, and overall user experience. This is difficult to achieve through purely automated testing.

Advantages of Automation Testing Over Manual Testing

Repetitive or large-scale tests become tedious and error-prone with manual execution. Automation excels in these scenarios, offering speed, consistency, and repeatability.

Testers can miss defects due to fatigue, bias, or incorrect test case design. Automation scripts, if well-designed, can eliminate such human errors.

Manually testing all possible scenarios and combinations is often impractical due to time constraints. Automation allows for exhaustive testing and can cover edge cases more efficiently.

As the software evolves, manual test cases need constant updates, which can be time-consuming and error prone. Automation scripts, once properly developed, can easily adapt to changes with less maintenance effort.

Measuring the effectiveness of manual testing can be subjective and relies heavily on individual tester skills and interpretations. Automation provides clear data and reports on test execution and results.

Manual and Automation Testing for Optimal Results

The key to achieving optimal testing results lies in understanding the strengths and weaknesses of both approaches and using them strategically. Here’s how to combine them effectively:

Use Automation on Repetitive Tasks: Use automation for regression testing, API testing, and other repetitive tasks to free up tester time for more exploratory work.

Leave Room for Manual Testing: Allow testers to explore the software freely after automated tests to uncover any missed bugs or usability issues.

Balance Speed with Criticality: Don’t rely solely on automation for comprehensive testing. Combine automated tests with manual (ad-hoc testing) to get a more complete picture.

Select the Right Tool: Select the appropriate automation framework and tools based on the specific testing needs and the skillset of your team.

Continuous Improvement: Continuously refine and improve your testing strategy based on your experiences and the evolving software.

Final Words

Both manual and automated approaches hold their own — with their distinctive strengths and weaknesses.

So, selecting the right testing approach is not an “either/or” proposition — we need both.

By understanding the unique advantages of each technique, we can utilize them together for efficient testing.

Automation’s speed and precision for repetitive tasks, combined with a manual tester’s creativity and critical thinking makes for a holistic test coverage.

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