Software Testing

 

What is Software Testing?

Software testing is the process of evaluating and verifying that a software application works as intended, meets requirements, and is free from defects.

In Java/Spring Boot applications, testing ensures

  • APIs return expected results.

  • Business logic functions correctly.

  • The system is performant, secure, and reliable before deployment.

Why Software Testing is Important

  • Detects bugs early → Saves cost and time

  • Improves code quality → Cleaner, maintainable application

  • Ensures business requirements are met

  • Enhances performance and security

  • Supports CI/CD with confidence


Categories of Testing

Category

Definition

Focus

Spring Boot Example

Common Tools

Functional Testing      

Verifies that each function of the software operates according to requirement specifications.

What the system does.

Test /api/orders POST API updates DB and returns confirmation.

Selenium, Postman, RestAssured, JUnit, TestNG, Cucumber

Non-Functional Testing.              

Validates performance, security, scalability, and usability aspects.

How the system performs.

Ensure /api/products responds in <200ms under normal load.

JMeter, LoadRunner, OWASP ZAP, Burp Suite, Lighthouse

1. Functional Testing Types (Manual & Automation)

Type

Description

Example (Spring Boot)

Manual Tools

Automation Tools

Unit Testing

Test smallest code units.

Test UserService.getUserById()

IDE Console

JUnit, TestNG, Mockito

Integration Testing

Test interaction between modules.

Controller + Service + Repository.

Postman, DB Client

Spring Boot Test, MockMvc

System Testing

End-to-end full app testing.

Login → Place Order → Verify Invoice

Postman, Browser

Selenium, Cypress

API Testing

Validate REST endpoints.

/api/users POST + GET.

Postman

RestAssured, Newman

Acceptance Testing (UAT)

Verify against business needs.

Client checks order tracking feature.

None specific

Cucumber (BDD)

Smoke Testing

Quick basic checks.

/health endpoint returns OK.

Postman

REST Assured

Sanity Testing

Narrow tests after small changes.

Password reset after update.

Postman

JUnit

Regression Testing

Verify old features after changes.

Re-run login/order/payment flows.

Excel test cases

Jenkins + JUnit/Selenium

Exploratory Testing

Unstructured bug hunt.

Invalid inputs in signup API.

None

None

Usability Testing

Check UX & ease of use.

Verify navigation menus are intuitive.

Browser

Cypress

2. Non-Functional Testing Types

Type

Description

Example (Spring Boot)

Tools

Performance Testing

Test speed, responsiveness, stability.

/api/orders under 500ms for 500 users.

JMeter, Gatling

Load Testing

Test expected workload.

5,000 requests/minute on /api/products.

JMeter

Stress Testing

Test beyond limits.

20k requests until crash.

Locust, JMeter

Security Testing

Identify vulnerabilities.

SQL injection on /api/login.

OWASP ZAP, Burp Suite

Scalability Testing

Measure performance under growth.

Double user load on /api/orders.

JMeter

Compatibility Testing

Works across environments.

API on Chrome, Firefox, Edge.

BrowserStack

Reliability Testing

Consistent output under repeated use.

Multiple DB writes without corruption.

Custom scripts


Manual vs Automated Testing

Manual Testing

  • Human executes test cases without tools.

  • Best for exploratory, usability, and ad-hoc testing.

  • Example: Manually POST /api/login in Postman and verify response.

Automated Testing

  • Scripts/tools run tests automatically.

  • Best for regression, load, and repetitive tests.

  • Example: JUnit + Mockito for service testing; MockMvc for API testing.


Types of Software Testing 

1. Manual Testing Types

Type

Definition

Who Does It

Unit Testing (Manual)

Directly executing code methods in IDE or console to verify logic without automation.

Developer

Integration Testing (Manual)

Manually checking that multiple modules work together correctly.

Developer / QA

System Testing

End-to-end testing of the full application as a complete system.

QA Engineer

User Acceptance Testing (UAT)

Testing done by client/end-users to validate business needs.

Client / Product Owner

Smoke Testing (Manual)

Quick manual check to ensure basic app functionality is working.

QA / DevOps

Sanity Testing

Focused check to confirm a specific bug fix or small change works.

QA Engineer

Regression Testing (Manual)

Re-running previous test cases manually after changes to ensure nothing is broken.

QA Engineer

Ad-hoc / Exploratory Testing

Unstructured creative testing to discover unexpected bugs.

QA Engineer

Usability Testing

Checking user interface for intuitiveness and ease of use.

QA / UX Designer

Compatibility Testing (Manual)

Verifying application works across multiple browsers, devices, or OS.

QA Engineer

Installation Testing

Ensuring the application installs and configures correctly in different environments.

QA / DevOps

2. Automated Testing Types

Type

Definition

Who Does It

Unit Testing (Automated)

Testing the smallest code units automatically using frameworks like JUnit.

Developer

Integration Testing (Automated)

Automated validation that modules and layers interact correctly.

Developer

API Testing (Automated)

Automated testing of REST endpoints for functionality and correctness.

QA / Developer

UI Testing (Automated)

Automated interaction with the web UI to verify expected results.

QA Engineer

Regression Testing (Automated)

Automated re-run of previous tests after code changes.

QA / Automation Engineer

Smoke Testing (Automated)

Automated basic check after deployment/build.

QA / DevOps

Performance Testing

Measuring speed, responsiveness, and scalability of the application.

Performance Engineer

Load Testing

Testing application behavior under expected normal load.

Performance Engineer

Stress Testing

Pushing the application beyond its limits to check stability.

Performance Engineer

Security Testing

Detecting security vulnerabilities in the system.

Security Engineer

Acceptance Testing (BDD)

Automated business-readable tests based on requirements (e.g., Cucumber).

QA / Product Owner

Contract Testing

Ensuring service-to-service API contracts remain intact (e.g., Pact).

Developer

Mutation Testing

Introducing small code changes to ensure tests detect them.

Developer

Chaos Testing

Intentionally breaking infrastructure/components to test resilience.

DevOps / SRE

Accessibility Testing

Ensuring app is usable by people with disabilities.

QA / Accessibility Specialist


Sequence of Testing in a Spring Boot Application

  1. Unit Testing → Developer (JUnit + Mockito)

  2. Integration Testing → Developer (Spring Boot Test, MockMvc)

  3. System Testing → QA (End-to-end API/UI tests)

  4. Smoke Testing → QA / DevOps (Quick health check /health)

  5. Sanity Testing → QA (Targeted checks after fixes)

  6. Regression Testing → QA / Automation Engineer (Automated suite run)

  7. Performance & Load Testing → Performance Engineer (JMeter, Gatling)

  8. Security Testing → Security Engineer (OWASP ZAP, Burp Suite)

  9. User Acceptance Testing (UAT) → Client / Product Owner

  10. Production Monitoring Tests → DevOps (Synthetic monitoring with tools like Grafana K6)


Detailed Types of Testing (Java / Spring Boot Context)

Type

Category

Manual / Automated

Who Does It

Description

Example in Spring Boot

Tools

Functional Testing

Functional

Both

QA / Dev

Verifies functional requirements

Test order placement API

JUnit, Postman

Non-Functional Testing

Non-Functional

Automated

QA / Perf Engg

Checks performance, security, scalability

Stress test /api/products

JMeter, Gatling

Unit Testing (Manual)

Functional

Manual

Dev

Direct method calls for debugging

Call UserService.createUser() in IDE

IntelliJ Console

Unit Testing (Automated)

Functional

Automated

Dev

Test smallest code units

UserService.getUserById()

JUnit, Mockito

Integration Testing (Manual)

Functional

Manual

QA / Dev

Manually test module interaction

UI → API → DB check

Postman, DB Client

Integration Testing (Automated)

Functional

Automated

Dev

Verify module interaction

@SpringBootTest with MockMvc

Spring Boot Test, MockMvc

System Testing

Functional

Manual

QA

End-to-end test

Login → Place Order → Download Invoice

Browser, Postman

Smoke Testing (Manual)

Functional

Manual

QA / DevOps

Quick health check

/health endpoint

Postman

Smoke Testing (Automated)

Functional

Automated

CI/CD

Basic CI checks

Test /health in pipeline

RestAssured, Jenkins

Sanity Testing

Functional

Manual

QA

Quick targeted tests

Verify login after bug fix

Postman

Regression Testing (Manual)

Functional

Manual

QA

Retest old features

Re-run payment flow after update

Test case sheet

Regression Testing (Automated)

Functional

Automated

Automation QA

Auto re-run suites

All test cases in CI

JUnit + Selenium

Ad-hoc / Exploratory Testing

Functional

Manual

QA

Creative bug finding

Try invalid payload in signup API

None

Usability Testing

Functional

Manual

QA / UX

User-friendliness test

Navigation flow check

Browser, Figma

API Testing (Automated)

Functional

Automated

QA

Validate REST APIs

/api/orders POST & GET

RestAssured, Postman

UI Testing (Automated)

Functional

Automated

QA

Test web UI

Order page loads correctly

Selenium, Cypress

Performance Testing

Non-Functional

Automated

Perf Engg

Speed under load

500 users hitting /api/products

JMeter, Gatling

Load Testing

Non-Functional

Automated

Perf Engg

Expected workload test

5k req/min

JMeter

Stress Testing

Non-Functional

Automated

Perf Engg

Beyond limits

20k req until crash

JMeter, Locust

Security Testing

Non-Functional

Both

Security Engg

Find vulnerabilities

SQL injection /api/login

OWASP ZAP, Burp Suite

Acceptance Testing (BDD)

Functional

Automated

QA / PO

Business-readable tests

Gherkin login scenario

Cucumber


Common Testing Types & Purposes

Type

Purpose

Unit Testing

Test individual components/modules

Integration Testing

Verify interaction between components

System Testing

Test full integrated system

Acceptance Testing

Validate against business needs

Regression Testing

Ensure updates don’t break old features

Performance Testing

Check speed, responsiveness, stability

Security Testing

Identify vulnerabilities & risks

Usability Testing

Test user-friendliness & UX


Common Tools

  • Manual Testing: JIRA, TestRail, Bugzilla (management/bug tracking)

  • Automation: Selenium, JUnit, TestNG, Cucumber, Appium

  • Performance: JMeter, LoadRunner

  • Security: OWASP ZAP, Burp Suite

  • CI/CD: Jenkins, GitLab CI/CD

  • Coverage: JaCoCo


Example Spring Boot Testing Scenarios

Automated API Test (JUnit + RestTemplate)

@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
class UserApiTest {
    @Autowired
    private TestRestTemplate restTemplate;

    @Test
    void testCreateUser() {
        UserDto user = new UserDto("alice", "alice@example.com", "pass123");
        ResponseEntity<UserDto> res = restTemplate.postForEntity("/api/users", user, UserDto.class);
        assertEquals(HttpStatus.CREATED, res.getStatusCode());
        assertEquals("alice", res.getBody().getUsername());
    }
}

Performance Test (JMeter)

  1. Create test plan for /api/orders

  2. Set 1000 concurrent users

  3. Verify average response time < 500ms


Key Notes in Spring Boot Context

  • Use @SpringBootTest for integration tests with full context load

  • Mock dependencies using Mockito for isolation

  • Use @WebMvcTest for controller-level testing without loading entire app

  • Generate coverage reports using JaCoCo in Maven/Gradle builds

  • Run tests in CI/CD pipelines before merging to main branch

  • Leverage test profiles (application-test.properties) for isolated DB configs

  • TestContainers can be used for real DB/integration testing in Docker during CI

  • Property-based testing with libraries like jqwik can improve input coverage

  • Use WireMock to simulate external service APIs during integration tests


Spring Boot Testing Best Practices

  • Unit Tests: JUnit + Mockito for service/repository layer

  • Integration Tests: @SpringBootTest for context testing

  • API Tests: Postman/RestAssured for endpoint testing

  • E2E Tests: Selenium/Cypress for UI flows

  • Coverage: Use JaCoCo to track coverage goals

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