Fall, 2006SW Eng Standalone Progs, Univ of Colorado Boulder 1 Wk 11 Glass Box Testing, Flow Graphs, Test Coverage SW Engineering of Standalone Programs

Fall, 2006SW Eng Standalone Progs, Univ of Colorado Boulder 2 Basis set for statement coverage testing Draw the flow graph Count the bounded regions including the “outside region” –N is the number of linearly independent paths through the program control structure –A linearly independent path includes one node of the control flow graph not contained in any other –Create a basis set of linearly independent paths Prepare test cases to force execution of each path in the basis set. Execution of these test cases yields ______ coverage

Fall, 2006SW Eng Standalone Progs, Univ of Colorado Boulder 3 Flow Graph: McCabe’s is 25

Fall, 2006SW Eng Standalone Progs, Univ of Colorado Boulder 4 Flow Graph Revelations

Fall, 2006SW Eng Standalone Progs, Univ of Colorado Boulder 5 Complexity impact

Fall, 2006SW Eng Standalone Progs, Univ of Colorado Boulder 6 Uses of Test Coverage Measurement Measure test suite completeness Identify risk areas –Combine execution counts with complexity –Understand complex code segments that are frequently executed –Understand criticality Assist in creating new test cases Assist in manual detection of faults Prioritize test cases for regression tests

Fall, 2006SW Eng Standalone Progs, Univ of Colorado Boulder 7 Some More Test Coverage terms

Fall, 2006SW Eng Standalone Progs, Univ of Colorado Boulder 8 Test Coverage Measures Completeness of Test Suite

Fall, 2006SW Eng Standalone Progs, Univ of Colorado Boulder 9 Test Coverage Measurement Minimize and select regression tests 377 Total Tests Blocks Decisions P-uses All-uses 75% 65% 38% 44% 160 Total Tests Blocks Decisions P-uses All-uses 75% 65% 38% 44% 18 Total Tests Blocks Decisions P-uses All-uses 62% 52% 30% 37% 42% of the original tests provide identical coverage 5% of original tests provide 85% of original coverage

Fall, 2006SW Eng Standalone Progs, Univ of Colorado Boulder 10 Unit Test Coverage vs System Test Errors

Fall, 2006SW Eng Standalone Progs, Univ of Colorado Boulder 11 System Test Observed & Expected Failures

Fall, 2006SW Eng Standalone Progs, Univ of Colorado Boulder 12 System Test Failure Rate over Active Hrs

Fall, 2006SW Eng Standalone Progs, Univ of Colorado Boulder 13 System Test Case Completion Graph

Fall, 2006SW Eng Standalone Progs, Univ of Colorado Boulder 14 HW 7 start of code getop(s, lim) /*get next operator or operand */ char all; int lim; { int i, c; while ((c = getch ( ) ) == ‘ ‘|| c == ‘\t’ || c == ‘\n’) ; if (c ! = ‘.’ && (c ’9’)) return (c); s[0] = c; for (i=1; (c=getchar()) >= ‘0’ && c <=‘9’; i++) if (i < lim) s[i] = c; if...

Fall, 2006SW Eng Standalone Progs, Univ of Colorado Boulder 15 Inspections

Fall, 2006SW Eng Standalone Progs, Univ of Colorado Boulder 16 What are inspections? Means of verifying work products Manual examination technique One piece at a time Small group of peers – at least 4

Fall, 2006SW Eng Standalone Progs, Univ of Colorado Boulder 17 Purpose Verification of a work product against –established criteria –product specifications

Fall, 2006SW Eng Standalone Progs, Univ of Colorado Boulder 18 How performed? Planning Overview Preparation Meeting Re-work Follow up

Fall, 2006SW Eng Standalone Progs, Univ of Colorado Boulder 19 Roles of participants Author Moderator Reader Recorder Inspector

Fall, 2006SW Eng Standalone Progs, Univ of Colorado Boulder 20 The meeting Each participant reports preparation time Reader paraphrases –Pace should be effective –Not too slow, not too fast Inspectors look, listen, and think simultaneously Author and inspectors speak up if they disagree with reader’s paraphrase – need to decide which is correct. If Reader, Recorder notes location & brief description of issue Moderator can adjust pace and “atmosphere”

Fall, 2006SW Eng Standalone Progs, Univ of Colorado Boulder 21 End of meeting Recorder’s list goes to author After rework, at a minimum, author reviews changes with one inspector. Better – inspect the changed item

Fall, 2006SW Eng Standalone Progs, Univ of Colorado Boulder 22 Benefits Errors found at faster rate Errors found early are cheaper to fix Cross-training Learn good and bad techniques by seeing them, e.g. coding techniques

Fall, 2006SW Eng Standalone Progs, Univ of Colorado Boulder 23 A Word about Extreme Programming My personal view of extreme programming is that Beck & Cunningham managed to incorporate many effective software engineering tasks into short iterations with high feedback. One example: pair programming is...