Test Design Techniques, Test Case Design & Test Planning

Test Design Techniques

Black-Box Techniques

Test without knowledge of internal code. Input → expected output.

Technique	When to use	Example
Equivalence Partitioning	Large input spaces	Age field: valid (0–120), invalid (<0, >120)
Boundary Value Analysis	Numeric ranges, limits	Age 0, 1, 119, 120, -1, 121
Decision Tables	Complex logic with multiple conditions	Discount rules: loyal + premium = 30% off
State Transition	Flows with states and events	Order: New → Paid → Shipped → Delivered
Use Case Testing	End-to-end user scenarios	"User places order, pays, receives confirmation"

White-Box Techniques

Test using knowledge of code structure.

Technique	Coverage metric	Focus
Statement coverage	% of lines executed	Basic code reachability
Branch coverage	% of branches (if/else) taken	Conditional logic paths
Path testing	All independent paths	Complex functions with many conditions

Experience-Based Techniques

Technique	Description
Exploratory testing	Simultaneous learning, design, and execution; use charters
Error guessing	Based on past bugs, common pitfalls, domain knowledge
Checklist-based	Reusable quality checklists for features or regression

Full technique deep-dives: Test Design Techniques

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Test Case Design

Test Case Structure

ID:          TC-001
Title:       User cannot log in with wrong password
Preconditions:
  - User account exists with email user@example.com
  - User is on the login page
Steps:
  1. Enter email: user@example.com
  2. Enter password: wrong_password
  3. Click "Login"
Expected result:
  - Error message: "Invalid credentials" is displayed
  - User stays on the login page
  - No session cookie is set
Actual result:   (filled during execution)
Status:          PASS / FAIL / BLOCKED

Principles for Good Test Cases

Principle	What it means
Clarity	Anyone can execute it without asking questions
Atomicity	One test case = one verifiable outcome
Independence	Does not depend on execution order or other tests
Reusability	Steps and data can be reused across similar cases
Maintainability	Easy to update when requirements change

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Test Planning

Test Plan

A document that answers: what, how, who, when, and where testing will happen.

Section	Contents
Scope	What is in / out of scope for testing
Objectives	What the test effort should achieve
Test levels & types	Which testing approaches will be used
Resources	Team, tools, environments needed
Schedule	Milestones, start/end dates
Risks & mitigations	What could block testing and how to handle it
Entry criteria	Conditions required to start testing
Exit criteria	Conditions required to declare testing complete

Test Strategy vs Test Plan

	Test Strategy	Test Plan
Scope	Organisation-wide or project-wide approach	Specific release or sprint
Audience	Management, architects	QA team, developers
Content	Test levels, tools, standards, approach	Concrete schedule, scope, resources
Stability	Rarely changes	Updated per release

Entry & Exit Criteria

Entry criteria — conditions that must be met before testing begins: - Build is deployed and stable - Requirements are reviewed and signed off - Test data and environments are ready

Exit criteria — conditions that declare testing done: - All planned test cases executed - No open Critical or High severity defects - Test coverage target met (e.g. 80% of requirements covered) - Test summary report approved by stakeholders