Testing software functionality thoroughly is imperative for technology teams serious about quality. System testing and end-to-end testing are two vital testing methods with that aim. But when should each be applied?
In this comprehensive 2600+ word guide, we’ll cover everything technology and data teams need to know about aligning system and end-to-end testing approaches with quality goals.
Introduction to Software Testing
Before diving deeper, let‘s define software testing overall. Software testing refers to evaluating a software application under development to detect gaps between expected and actual outcomes. By systematically testing functionality, the goal is identifying defects impacting correct performance or user experience.
Testing helps answer the question: Does this software solution meet specifications and perform as needed in the real world?
There are a variety of software testing types and methodologies. Some key testing approaches include:
- Unit testing – Validates individual code components work properly in isolation
- Integration testing – Checks combined software modules/components still function correctly
- System testing – Validates the completely integrated system against specified requirements
- End-to-end testing – Simulates real user scenarios from start to finish
The type of testing aligns to the software development lifecycle phase, mirroring code maturity. As development progresses from isolated units to full integration, testing must scale in scope accordingly. This catches issues early and prevents defects propagating downstream.
Now let‘s explore system and end-to-end testing methodologies more closely.
What is System Testing?
System testing evaluates the completely integrated software solution against specified business and technical requirements. The goal is confirming:
- All system elements interoperate correctly
- End user workflows perform as expected
- The system handles required load, data volumes, and use cases
System testing occurs after integration testing and before final user acceptance testing.
Goals and Benefits
Why invest effort in system testing? Key goals include:
- Finding defects not caught in isolated unit and integration testing
- Ensuring the integrated software works per all specified requirements
- Validating workflows, error handling, security controls, integrations all operate correctly
- Building confidence in solution quality before releasing to end users
- Identifying performance, scalability, reliability, or recovery issues
Per a 2022 survey from Capgemini, 61% of organizations rely on system testing to avoid software failure risks.^[1] Investing in rigorous system testing drives higher quality, security, and customer satisfaction outcomes.
How System Testing Is Performed
Typical system testing activities include:
- Planning – Define scope, environment, test data, scenarios, and metrics
- Test case development – Map requirements to detailed test cases and scripts
- Test execution – Execute test cases while recording pass/fail defects
- Defect logging – Document and report all observed env, functional, UX defects
- Regression testing – Re-run test cases to ensure fixes don‘t break other areas
- Reporting – Summarize exec status, quality metrics, key issues
Engineers rely on test case management tools to streamline this process. Popular open-source frameworks include Selenium, JUnit, TestNG, amongst others.
What is End-to-End Testing?
The goal of end-to-end (E2E) testing is verifying an application‘s workflow performs as expected from start to finish. The scope of end-to-end validation includes:
- User interfaces
- Backend databases
- External services/APIs
- Network connections
Testing realistically simulates how real users will interact with the workflow, including diverse actions, inputs, and data specific to the use case.
Goals and Benefits
Why invest in end-to-end testing? Goals include:
- Validating application workflows mirror diverse real-world usage
- Ensuring all components integrate seamlessly for complete workflows
- Confirming data integrity from end-to-end interaction
- Gaining confidence all workflows will perform reliably for users
Per Gartner research, 57% of end users will abandon software that doesn’t meet performance expectations.^[2] Rigorously testing user journeys end-to-end is imperative.
End-to-end testing provides that final level of confidence before releasing to customers.
Key Differences Between System and End-to-End Testing
While system and end-to-end testing aim to prevent defects, they take different approaches:
| System Testing | End-to-End Testing | |
|---|---|---|
| Scope | Validates entire integrated system | Tests customer workflows end-to-end |
| Focus | Tests functional components | Validates usage journeys |
| Purpose | Verifies against requirements | Confirms process output |
| Technique | Involves test automation | Often manual testing |
| Depth | Superset of E2E testing | Subset of system testing |
In summary:
- System testing takes a wide-lens view validating all integrated parts come together correctly
- End-to-end testing zooms in on target use cases assessing they work in practice
Think system testing → forest, end-to-end testing → trees.
Combined strategically, they provide comprehensive confidence in releasing high quality solutions.
Next let‘s explore key differentiators more closely.
Test Scope and Coverage
System testing aims to comprehensively test functionality across the entire solution per all specifications. Evaluating aspects like:
- Component integration
- Data structures
- Error handling
- User access
- Performance capacity
The scope attempts full coverage to catch gaps not revealed testing individual parts in isolation.
In contrast, end-to-end testing narrowly focuses on critical user workflows. Evaluating aspects like:
- Process completion
- Data continuity
- Runtime performance
The in-depth scope verifies selected use cases will work reliably for target customer segments.
Think mile wide + inch deep vs. mile deep + inch wide.
Automation Feasibility
System testing frequently relies on test automation to achieve sufficient coverage economically. Test scripts exercise:
- Application interfaces
- API calls
- Database operations
Popular open-source tools like Selenium or proprietary tools like Tricentis Tosca drive automation.
However, end-to-end testing generally requires more manual testing. Why? End-user workflows cut across systems involving:
- Mainframes
- Microservices
- Cloud platforms
- 3rd party APIs
As Gartner notes, the interconnectedness poses automation challenges.^[3] Instead, QA focuses manual testing on high-risk journeys.
This balanced approach increases overall test coverage.
Deciding Between System vs End-to-End Testing
Choosing between system testing and end-to-end testing depends on risk, timelines, and test objectives like:
Verify component integration – system test combined solution
Validate requirement specifications – system test against specs
Prove user-journey quality – end-to-end replicate workflows
Analyzing project unknowns guides smart testing investment. Often both system and end-to-end testing practices are leveraged in succession.
System testing first checks integrated functionality matches specifications. Then end-to-end testing replicates just enough critical user workflows expected to drive adoption.
Informed testing strategy maximizes risk mitigation given timeline constraints using each method‘s strengths.
Conclusion
Understanding core differences between system and end-to-end testing enables technology and data teams to balance approaches strategically. Carefully validating software from both wide and deep angles provides rounded confidence in releasing quality data solutions securely and reliably.
System testing first checks integrated components work correctly together. End-to-end testing then confirms targeted user workflows perform without error across all the interconnected infrastructure relied on in production.
Combining system and end-to-end testing practices thoughtfully allows quality-focused engineering teams to prevent defects proactively. This helps technology transformation initiatives meet business objectives and customer expectations.
- Capgemini, "The Digital Testing Survey Report 2022", 2022
- Gartner Research, "How to Measure Digital Experience to Deliver Superior CX", 2022
- Gartner Research, "Top Challenges to Test Automation"