Glass-box Testing

Three Types of Coverage Model

1. Control Flow
   1. Model the flow of control
   2. Examples: node coverage, edge coverage
2. Logic
   1. Analyse the influence of all Boolean variables
   2. Examples: predicate coverage, clause coverage, MCDC (FAA DO178B)
3. Data Flow
   1. Measure the flow of data between variable assignments (writes) and variable references (reads).
   2. Examples: all-definitions, all-uses

Test Requirements

• Generated by a coverage model
• Easy to measure coverage

Condensation Graph

A node is either an Assignment block or a Boolean condition.

Satisfying a Coverage Model

Type 1: Control Flow

Node Coverage (NC)

Each reachable path p of length 1 in G is a test requirement.
覆盖每个点

Edge Coverage (EC)

Each reachable path p of length 2 in G is a test requirement.
覆盖每条边

Edge-Pair Coverage (EPC = EC2)

Each reachable path p of length <= 3
每种path可能性（2个if串联就有2*2=4种可能性）

Prime Path Coverage (PPC)

Each reachable prime path p in G is a test requirement
Prime Path: maximal simple path 最长简单路（除去首尾，中间不能重复）
满足: p cannot be extended without losing simplicity 再长一点就不是simple path

Complete Path Coverage (CPC)

Every reachable path in $G$ is contained in some path $p \in TR$.

Type 2: Logic Coverage

• 重点: Different ways of taking the same branch
• For logic coverage, a test requirement tr is a logical constraint on input data values

Predicate Coverage (PC)

For each predicate $p \in P$, the set TR contains:

1. a requirement that implies p is reached and evaluates to true
2. a requirement that implies p is reached and evaluates to false

Clause Coverage (CC)

• 比CC粒度更细，每个clause都要为true或false（这里clause指atomic表达式）
• PC和CC互相independent（可能一个满足一个不满足）

Combinatorial Coverage (CoC)

For each predicate $p \in P$, and every possible truth assignment $\alpha$ to the clauses Cp of p the set TR contains a requirement which implies p is reached and the clauses evaluate to $\alpha$.

Active Clause Coverage (ACC)

For each predicate $p \in P$ and each clause $c \in C_p$ which determines p (under some $\alpha$), the set TR contains two requirements for c: c is reached and evaluates to true, and c is reached and evaluates to false.

• Determination: 在一个predicate里只改变一个clause，predicate的值被改变
• 通过Truth Table可以找出determination
• Problems of masking, logical overlap and side-effects

General Active Clause Coverage (GACC)

• ACC的定义加上: The values chosen for the other clauses $d \in C_p$ , $d \neq c$, need not be the same in both cases.
• 先找到determination，但是其他的clauses的赋值要不一样

Restricted Active Clause Coverage (RACC)

• ACC的定义加上: The values chosen for the other clauses $d \in C_p$ , $d \neq c$, must be the same in both cases.
• 先找到determination，但是其他的clauses的必须一样
• Problem: 可能不满足PC，难以处理synonyms

Correlated Active Clause Coverage (CACC)

• ACC加上: The values chosen for the other clauses $d \in C_p$ , $d \neq c$, must cause p to be true in one case and false in the other.
• 其他clauses可以变，但整个predicate至少能为true或者false

Type 3: Data Flow

• A definition of a variable v is any statement that writes to v in memory
• A use of v is any statement that reads v from memory.

All-defs Coverage (ADC)

See slides.

All-uses Coverage (AUC)

See slides.

All-du-paths Coverage (ADUPC)

See slides.