Why one unchecked defect can cost millions
A single missed defect in a payment flow, medical device, or safety system can cascade into financial loss, reputational damage, or even harm. Testing is not just "finding bugs" — it is about providing confidence that the product meets its intended purpose under expected conditions.
// example: netflix streaming quality
What testing means per CTFL 4.0.1
Testing is the process consisting of all lifecycle activities, both static and dynamic, concerned with planning, preparation and evaluation of software products and related work products to determine that they satisfy specified requirements, to demonstrate that they are fit for purpose and to detect defects.
Key concepts
- Testing evaluates quality and helps manage risk
- Testing can show presence of defects, not their absence
- Testing includes static activities (reviews, analysis) and dynamic activities (executing the software)
- Testing provides information for stakeholders to make informed decisions
// tip: Exam Tip: Testing's primary purpose is not to "break software" but to provide information about quality and risk to stakeholders.
| Step | Action | CTFL Concept Applied |
|---|---|---|
| 1 | Review requirements for login: valid credentials, invalid credentials, lockout after 3 failed attempts | Requirements-based testing |
| 2 | Identify test conditions: correct password, wrong password, empty fields, SQL injection attempt | Test analysis |
| 3 | Design test cases with expected results for each condition | Test design |
| 4 | Execute tests in a controlled environment | Test execution |
| 5 | Compare actual vs expected results, log defects if mismatch | Defect reporting |
| 6 | Report test coverage and residual risk to stakeholders | Test completion |
Evaluate Quality
Assess if product meets requirements and is fit for purpose
// CTFL 4.0.1 alignment
Testing provides information about quality and risk to stakeholders.
| Lifecycle Phase | Testing Activity | Goal |
|---|---|---|
| Requirements | Review specifications for testability, ambiguity, conflicts | Prevent defects early |
| Design | Evaluate architecture, identify test conditions | Align tests with structure |
| Implementation | Execute dynamic tests, log defects | Detect defects in code |
| Release | Confirm exit criteria met, assess residual risk | Support go/no-go decision |
| Maintenance | Regression testing after changes | Ensure no new defects introduced |
// warning: Exam Trap: Do not confuse "testing" with "debugging". Testing finds defects; debugging is the development activity to locate and fix the root cause.
Exam Practice Questions
// ctfl 4.0.1 style — select an answer to reveal explanation