Table of contents
1.1 Statement coverage method (C0 standard)
1.2 Judgment/branch coverage method (C1 standard)
1.3 Conditional coverage method (C2 standard)
1.4 Judgment condition coverage method (C1+C2 standard)
1.5 Condition combination coverage method (C3 standard)
1.7 Basic Path Covering Method
1.0 Flowchart Identification
1.1 Statement coverage method (C0 standard)
① target
Every executable statement in the program is executed at least once
If it is not explained later, this example is still used
Program source code:
import java.util.Scanner;
public class Demo {
public static void main(String[] args) {
int a, b;
double c;
Scanner scanner = new Scanner(System.in);
a = scanner.nextInt();
b = scanner.nextInt();
c = scanner.nextDouble();
if (a > 0 && b > 0) {
c = c / a;
} else if (a > 1 || c > 1) {
c = c + 1;
}
c = b + c;
System.out.println("a=" + a);
System.out.println("b=" + b);
System.out.println("c=" + c);
scanner.close();
}
}
Draw a flowchart:
② use case
| enter | output |
|---|---|
| a = 2 b = 1 c = 6 | a = 2 b = 1 c = 7 |
③ Advantages and disadvantages
- Statement coverage can find statement errors
- Statement coverage cannot find logic errors
1.2 Judgment/branch coverage method (C1 standard)
① target
The true branch and false branch of each decision in the program are executed at least once
② use case
| enter | output |
|---|---|
| a = 2 b = 1 c = 6 | a = 2 b = 1 c = 5 |
| a = -1 b = 1 c = 1 | a = -1 b = 1 c = 7 |
③ Advantages and disadvantages
- Decision/branch coverage can find logic errors
- Decision/branch coverage cannot find conditional errors in combined judgments
1.3 Conditional coverage method (C2 standard)
① target
The possible value of each condition in each judgment in the program is satisfied at least once
② use case
Judgment 3: (a > 0 && b > 0)
Judgment 6: (a > 1 || c > 1)
Atomic conditions:
a > 0
b > 0
a > 1
c > 1
Requirement: Each atomic condition set is true and false once
| enter | atomic conditions | Judgment conditions |
|---|---|---|
| a = -1 b = 2 c = 3 | a>0 is false, b>0 is true, a>1 is false, c>1 is true | Judgment 3 is false, judgment 6 is true |
| a = 2 b = -1 c = -2 | a>0 is true, b>0 is false, a>1 is true, c>1 is false | Judgment 3 is false, judgment 6 is true |
③ Advantages and disadvantages
- Not necessarily more comprehensive than decision/branch coverage
- Cannot detect logic errors
1.4 Judgment condition coverage method (C1+C2 standard)
① target
All possible values in each condition are executed at least once , and at the same time, the possible results of each decision are executed at least once
② use case
| enter | atomic conditions | Judgment conditions |
|---|---|---|
| a = 2 b = 1 c = 4 | a>0 is true, b>0 is true, a>1 is true, c>1 is true | Judgment 3 is true, judgment 6 is true |
| a = -1 b = -2 c = -3 | a>0 is false, b>0 is false, a>1 is false, c>1 is false | Judgment 3 is false, judgment 6 is false |
③ Advantages and disadvantages
- may cause some conditions to mask others
1.5 Condition combination coverage method (C3 standard)
① target
All conditional value combinations in each judgment are executed at least once
② use case
Judgment 3: (a > 0 && b > 0)
Judgment 6: (a > 1 || c > 1)
Atomic conditions:
a > 0 b > 0 a > 1 c > 1
Require:
When a>0, b>0 is true and false once
When a<=0, b>0 is true and false once
When a>1, c>1 is true and false once
When a<=1, c>1 is true and false once
| enter | atomic conditions | Judgment conditions |
|---|---|---|
| a = 2 b = 1 c = 6 | a>0 is true, b>0 is true, a>1 is true, c>1 is true | Judgment 3 is true, judgment 6 is true |
| a = 2 b = -1 c = -2 | a>0 is true, b>0 is false, a>1 is true, c>1 is false | Judgment 3 is false, judgment 6 is true |
| a = -1 b = 2 c = 3 | a>0 is false, b>0 is true, a>1 is false, c>1 is true | Judgment 3 is false, judgment 6 is true |
| a = -1 b = -2 c = -3 | a>0 is false, b>0 is false, a>1 is false, c>1 is false | Judgment 3 is false, judgment 6 is false |
③ Advantages and disadvantages
- More comprehensive than condition coverage
1.6 Path coverage
① target
Use cases cover all possible execution paths in a program
② use case
| enter | atomic conditions | Judgment conditions |
|---|---|---|
| a = 2 b = 1 c = 6 | a>0 is true, b>0 is true, a>1 is true, c>1 is true | Judgment 3 is true, judgment 6 is true |
| a = 1 b = 1 c = -3 | a>0 is true, b>0 is true, a>1 is false, c>1 is false | Judgment 3 is true, judgment 6 is false |
| a = -1 b = 2 c = 3 | a>0 is false, b>0 is true, a>1 is false, c>1 is true | Judgment 3 is false, judgment 6 is true |
| a = -1 b = -2 c = -3 | a>0 is false, b>0 is false, a>1 is false, c>1 is false | Judgment 3 is false, judgment 6 is false |
③ Advantages and disadvantages
- unrealistic
- because of the relatively long and almost infinite number of paths involved
- Any possible loop is considered as a possible path in the block
1.7 Basic Path Covering Method
1) McCabe's base path method
2) Number of linearly independent paths from source node to sink node (calculated according to cyclomatic complexity)
- V(G) = e - n + 2p = 10 - 7 + 2 = 5
- When the scale is small, we can visually identify independent paths
3) Given below is a path represented by a sequence of nodes/edges:
- p1：A,B,C,G/1,4,9
- p2：A,B,C,B,C,G/1,4,3,4,9
- p3：A,B,E,F,G/1,5,8,10
- p4：A,D,E,F,G/2,6,8,10
- p5：A,D,F,G/2,7,10
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epilogue
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