Testing. Jessica Young Schmidt, Northeastern University College of Computer and Information Science

Transcription

1 Testing Jessica Young Schmidt, 2012 Northeastern University College of Computer and Information Science

2 Why Test? Validation: Are we building the right product? - Increase confidence that software works correctly Find bugs Jessica Young Schmidt, Northeastern University College of Computer and Information Science

3 Black-box testing - Based on what the software should do White-box testing - Based on knowledge of requirements, design, and implementation Jessica Young Schmidt, Northeastern University College of Computer and Information Science

4 Types of Black-Box Testing Requirements Equivalence Partitioning Boundary Testing Jessica Young Schmidt, Northeastern University College of Computer and Information Science

5 Types of White Box Testing Statement Coverage Branch Coverage Path Coverage Equivalence Partitioning Boundary Value Jessica Young Schmidt, Northeastern University College of Computer and Information Science

6 int computefine(int dayslate, boolean printon){ 1 int MAX_FINE_PERIOD=21; fine=0; 2 if (dayslate<=max_fine_period){ 3 fine = dayslate * DAILY_FINE; 4 logfine(fine); 5 if (printon == TRUE){ 6 printfine(fine); 7 return fine; False True 3 True Test Case # daylate printon Path 1 1 TRUE False 7 6 Figure from Braude & Bernstein 2010 John Wiley & Sons Ltd. 10

7 int computefine(int dayslate, boolean printon){ 1 int MAX_FINE_PERIOD=21; fine=max_fine; 2 if (dayslate<=max_fine_period){ 3 fine = dayslate * DAILY_FINE; 4 logfine(fine); 5 if (printon == TRUE){ 6 printfine(fine); 7 return fine; Test Case #1 Test Case #2 1 1 False 2 4 True 3 False 2 4 True 3 5 True 5 True False 6 False Figure from Braude & Bernstein 2010 John Wiley & Sons Ltd. 11

8 Path Coverage All distinct code paths are executed by at least one test case Complete set of sequences of branches and loop traversals Subsumes statement and branch coverage Jessica Young Schmidt, Northeastern University College of Computer and Information Science

9 Path Coverage Number of distinct paths grow exponentially Basis paths - linearly independent paths - Minimum number of paths that can be combined to generate every possible path Cyclomatic complexity (CC) - CC = Edges Nodes CC = Predicate Nodes + 1 Jessica Young Schmidt, Northeastern University College of Computer and Information Science

10 Control Flow Diagram Pictorial description of the flow of program control Diamonds: decisions Rectangles: program statements Break apart compound conditionals 2010 Sarah Heckman 14

11 Control Flow Templates for"and"while"loops" do-while"loops" Sequen)al"if"" Statements" F& T& if"statement" F& F& T& T& if/else"statement" 2010 Sarah Heckman Nested&& if/else/if&& Statements& 15

12 Compound Predicates Control Flow Templates if" e" predicate1 && predicate2" F# F# T# T# if# e# predicate1 predicate2# 2010 Sarah Heckman 16

13 StringAnalyzer Problem A client wants to collect information about the types of characters users use in a String input to a program. Specifically, the client wants to collect the number of times a digit between a minimum and maximum value, inclusive, is used in String input. The user specifies the string input, a minimum, and a maximum value. If the minimum and maximum values are not valid digits or if the maximum is less than the minimum, the error message, Invalid bounds is displayed to the user. Otherwise, the count of digits between the minimum and maximum values, inclusive, is displayed to the user in the following output: The String contains X digits between minimum and maximum, inclusive Sarah Heckman (sarah_heckman@ncsu.edu) 17

14 StringAnalyzer.countDigits() public class StringAnalyzer { public static int countdigits(string line, char min, char max) { int digitcount = 0; if (checkbounds(min, max)) { for (int i = 0; i < line.length(); i++) { char c = line.charat(i); if (c >= min && c <= max) { digitcount++; else { digitcount--; return digitcount; 2010 Sarah Heckman (sarah_heckman@ncsu.edu) 18

15 1" int"digitcount"="0;" 2" checkbounds (min,max)" 8" digitcount"="<1;" 4" char"c"=" line.charat(i);" 3" i"<"line.length()" 9" return" digitcount;" 5" c">="min" 6" c"<="max" 7" digitcount++;" 2010 Sarah Heckman 19