TESTING

Software Engineering tutorial · PySpark.in

1. INTRODUCTION TO SOFTWARE TESTING

Definition

Software Testing is the process of evaluating a software system to identify defects, ensure quality, and verify that the software meets user requirements.

Objectives

• Find defects

• Ensure quality

• Prevent failures

• Verify requirements

• Validate customer expectations

• Reduce maintenance cost

• Improve reliability

Why Testing is Important?

• Software is complex

• Users expect high reliability

• Failures cause financial loss

• Defects cost more when found late

• Better user satisfaction

⭐ 2. SOFTWARE QUALITY

Quality

Degree to which software meets customer expectations.

Quality Assurance (QA)

• Process-oriented

• Ensures correct processes are followed

• Prevents defects

Quality Control (QC)

• Product-oriented

• Ensures the product meets quality standards

• Detects defects

Difference: QA vs QC

⭐ 3. VERIFICATION & VALIDATION (V&V)

Verification

“Are we building the product right?”
Ensures the software meets design and requirements.

Validation

“Are we building the right product?”
Ensures the final product matches user needs.

Difference:

⭐ 4. SOFTWARE TESTING LEVELS

1. Unit Testing

• Testing individual modules

• Done by developers

• Tools: JUnit, NUnit

• Focus: Functions, logic, loops

2. Integration Testing

Tests combined modules.
Types:

• Big Bang

• Top-down

• Bottom-up

• Sandwich (Hybrid)

3. System Testing

• Complete application testing

• Done by independent testers

• Functional + Non-functional testing

4. Acceptance Testing

Performed by client/user
Types:

• UAT – User Acceptance Testing

• Alpha Testing

• Beta Testing

⭐ 5. SOFTWARE TESTING TECHNIQUES

A. Black-Box Testing

Focus on inputs & outputs, NOT internal code.

Techniques:

1. Equivalence Partitioning

   • Divide input into valid/invalid classes

2. Boundary Value Analysis

   • Test at boundaries (min, max, min+1, max-1)

3. Decision Table

   • For complex business rules

4. State Transition

   • Based on states & events (ATM, login)

5. Use Case Testing

   • End-to-end scenarios

B. White-Box Testing

Focus on internal code.

Techniques:

1. Statement Coverage

2. Branch/Decision Coverage

3. Condition Coverage

4. Path Coverage

5. Loop Testing

C. Gray-Box Testing

Combination of both. Tester knows logic partially.

⭐ 6. TESTING TYPES

Functional Testing

• Smoke testing

• Sanity testing

• Regression testing

• Retesting

• Exploratory testing

• Ad-hoc testing

Non-Functional Testing

• Performance testing

• Load testing

• Stress testing

• Volume testing

• Security testing

• Compatibility testing

• Usability testing

• Reliability testing

• Recovery testing

⭐ 7. STATIC TESTING

No code execution.

Includes:

• Reviews

• Walkthroughs

• Inspections

• Static analysis tools

⭐ 8. DYNAMIC TESTING

Requires execution of software.

⭐ 9. SMOKE, SANITY, REGRESSION

Smoke Testing

• Basic build acceptance test

• Ensures major functions work

Sanity Testing

• Narrow & deep test

• Checks specific functions after a build

Regression Testing

• Ensures new changes didn’t break old features

• Automated tools: Selenium, Cypress, QTP

⭐ 10. SOFTWARE TESTING LIFE CYCLE (STLC)

1. Requirement Analysis

2. Test Planning

3. Test Case Design

4. Test Environment Setup

5. Test Execution

6. Defect Reporting

7. Test Closure

⭐ 11. DEFECT LIFE CYCLE

Defect States:

• New

• Assigned

• Open

• Fixed

• Retest

• Verified

• Reopen

• Closed

• Deferred

• Rejected

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