ISTQB Chapter 4: Complete Guide to Test Design Techniques

Why Chapter 4 Matters Most

ISTQB Chapter 4 covers test analysis and design, and it accounts for 27% of the Foundation Level exam. That is roughly 11 out of 40 questions. If you master the test techniques explained in this chapter, you have a significant advantage. Many candidates underestimate this section and pay the price on exam day.

This guide walks through every test design technique in the ISTQB Chapter 4 syllabus with clear explanations and practical examples.

Black-Box Test Techniques

Black-box techniques derive test cases from the specification without knowledge of the internal code structure. The ISTQB syllabus covers four black-box techniques at Foundation Level.

Equivalence Partitioning (EP)

Equivalence partitioning divides input data into groups (partitions) where all values in a partition are expected to be treated the same way by the system. You test one representative value from each partition instead of testing every possible input.

Example: An age field accepts values 18-65. The partitions are: below 18 (invalid), 18-65 (valid), and above 65 (invalid). You would test one value from each partition, such as 10, 30, and 80.

Boundary Value Analysis (BVA)

BVA focuses on the edges of equivalence partitions where defects are most likely to occur. For the age field example (18-65), two-value BVA tests: 17, 18, 65, and 66. Three-value BVA adds the values just inside the boundary: 17, 18, 19, 64, 65, 66.

Decision Table Testing

Decision tables capture complex business rules involving combinations of conditions. Each column represents a unique combination of conditions and the expected actions. This technique is powerful for testing business logic with multiple interacting conditions.

State Transition Testing

State transition testing models system behavior as states and transitions between them. You create a state diagram showing valid (and invalid) transitions, then derive test cases to cover each transition. This is particularly useful for testing workflows, user sessions, and protocol implementations.

White-Box Test Techniques

White-box techniques use knowledge of the internal code structure to design tests.

Statement Coverage

Statement coverage measures the percentage of executable code statements exercised by your tests. 100% statement coverage means every line of code has been executed at least once. This is the weakest form of structural coverage.

Branch Coverage

Branch coverage measures whether each branch of every decision point has been executed. For an if-else statement, you need tests that make the condition both true and false. 100% branch coverage guarantees 100% statement coverage, but not vice versa.

Experience-Based Techniques

Error Guessing

Error guessing uses the tester's experience to anticipate likely defects. Common targets include null values, empty strings, boundary conditions, and division by zero.

Exploratory Testing

Exploratory testing combines test design and execution simultaneously. The tester learns about the system while testing it, using session-based time-boxed approaches guided by a test charter.

How to Study Chapter 4

The ISTQB Chapter 4 test techniques require practice, not just reading. Work through examples for each technique until you can apply them quickly. Focus especially on EP and BVA since these appear most frequently on the exam.

Practice applying these techniques with our free ISTQB practice questions — many of our Chapter 4 questions require you to calculate test cases using these exact methods.