Discover the Difference

All About Automated Testing Vs Manual Testing


Most software teams utilize a combination of both manual and automated testing approaches to verify application quality and functionality. Manual testing leverages human testers physically executing test cases while automated testing uses scripts and code to simulate user interactions. Both automated testing vs manual testing have their own strengths and shortcomings. Evaluating automated versus manual testing tradeoffs is key for organizations to optimize overall test strategies and outcomes.

Time Investment

One of the starkest contrasts between manual and automated processes is the time investment required to prepare tests as well as execute test runs. For manual testing, test case design tends to be relatively fast. Testers can quickly outline steps users would take and expected system responses without much overhead. The test execution itself though tends to be extremely slow and time-consuming. Testers have to manually walk through scenarios step-by-step.

Conversely, setting up automated tests requires substantial upfront effort to write scripts that simulate user actions. Design of test logic and conditions, script configuration, object property identification, environment setup, and debugging scripts are all very time intensive processes before being “ready to test”. However, once scripts are complete, they can then execute extremely fast and be rerun with just one click. Ongoing execution time is near instant regardless of test length or complexity.

Defect Detection

Software quality relies heavily on the ability of testing to detect bugs, flaws, and gaps early so they can be fixed prior to release. For many simpler validation needs, manual testing traditionally identifies a respectable portion of defects. However, manual testing struggles to replicate highly complex workflows or scenarios exceeding human speed and scale capabilities. Many cases like high volume stress testing, intricate integration points, or exhaustive parameter combinations simply aren’t feasible manually.

Test automation provides huge benefits detecting defects that evade manual methods. Automated testing can simulate workflows much faster and at greater scale than humanly possible. Tests can execute 24/7 allowing for extremely lengthy processes to be validated overnight unattended. Automation also easily handles highly complex tasks humans would struggle to attempt or have capacity for like testing all backend computational branches. The expanded coverage leads to far more defects detected.

Consistency & Repeatability

Human executions rely considerably on intuition, judgment calls and some randomness during test case administration. Runs can deviate based on energy levels, variations in environmental conditions, errors in documenting steps, distractions or multi-tasking etc. Such volatility raises risks of tests not adequately covering agreed requirements or use cases. Reproducing manual test failures is also problematic because the precise steps preceding the failure are usually uncertain. 

In contrast, automated tests perform precisely the exact same scripted actions consistently every single run regardless of external factors. Results vary only when application behavior changes. The uniformity also allows for any prior test run to be reproduced which greatly aids troubleshooting test failures. The consistency, completeness and repeatability of automation eases debugging processes considerably over manual testing unpredictability.


While automated testing does carry high initial time investment in script creation, efficient teams minimize repetitive work through test maintenance processes. Script libraries and frameworks allow for modular functions that can be reused across many test cases alleviating redundant efforts. As application changes occur, updating affected test cases is vastly faster than rewriting them from scratch. Higher script reuse and easier maintenance makes evolving test suites simpler than manually administering similar scope of changes.

For manual testing, time savings from maintenance tend to be more marginal. While past test cases can be leveraged as a starting point for related new tests, execution steps still have to be completely revalidated manually against any changes made in the application. Unlike automated script updates, manual test changes cannot be partially applied. This tends to consume greater comparative maintenance efforts for keeping pace with application changes released over time.

Endurance & Reliability

Testing modern complex applications can involve extremely lengthy, tedious and multifaceted processes to adequately validate all scenarios. Human stamina and focus limitations prevent manual testing from being able to continue such rigorous demands beyond relatively short periods of time. The longer test executions run though, the higher defect detection and coverage will be. Automation addresses this through infinitely scalable scripts capable of executing well beyond human capacities 24/7 without tiring if needed.

Technology also holds much higher reliability over human judgment when it comes to precise test administration without deviation. While testers do bring value determining which test cases should execute based on risk evaluation, their manual execution reliance comes with higher probability of human error. Such mistakes unfortunately reduce analysis effectiveness and quality. Automation eliminates the risk of human slip ups skewing test runs.


In reality, neither manual testing nor test automation can offset all respective weaknesses of the other on their own. An optimized balance of manual and automated testing practices calibrated to application risk potential and layered into a unified quality strategy delivers immense synergies. Savvy teams understand both methodologies’ individual pros, cons and use cases. 

Aligning automated and manual solutions to complement each other based on context holds the key to managing testing efficacy, speed and cost. Opkey streamlines your testing process with a no-code automated testing solution. As one of the leading ERP testing tools, Opkey seamlessly integrates with your CI/CD pipelines for continuous testing. Gone are the days of lengthy setup – with Opkey, you can implement test automation from day one. Reduce manual testing efforts by up to 80% while maintaining code quality.

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