06/12/2007SE _6_12_Design.ppt1 Design Phase Outputs: Completed & Inspected SDS & Integration Test Plan Completed & Inspected System Test Plan Completed Inspection forms (INS) Completed & Inspected Design, Coding & Naming Standards Updated SUMP form & measurement data collected Time, defect & size data collected Updated project notebook Note: On baselining SDS, the document should be placed under change control

06/12/2007SE _6_12_Design.ppt2 Software Design Specification (SDS) Input Conceptual Design Requirements (SRS) Design Objectives Principal parts How the parts interact How they are put together Recommendation: assign only 1 to 2 developers to produce SDS

06/12/2007SE _6_12_Design.ppt3 Design Standards Naming conventions Function, File, Variable, Parameter Names Defines, Globals, Public, Statics, etc. Interface formats Variable handling Error codes System & Error messages Defect standards Severities Defect types Root cause bucketing LOC counting

06/12/2007SE _6_12_Design.ppt4 Design for Reuse Reusable functions should be: Self contained Cleanly isolated Clearly & concisely documented (usage, interfaces, returns, errors) Examples of successful reusable components?

06/12/2007SE _6_12_Design.ppt5 Design for Testability Unit test harnesses Simulation testing Black box testing Verify program’s external interfaces White box testing Also considers program’s logical paths & structure Typically requires special tools (e.g. code coverage) Typically requires supporting code

06/12/2007SE _6_12_Design.ppt6 Integration Test Plan Objective Verify all system component interfaces Activity Review all interfaces (as defined in SDS) Specify how to test them Recommend: inspecting SDS & Integration Test Plan simultaneously Could also combine into a single document

06/12/2007SE _6_12_Design.ppt7 System Test Plan Areas to cover: Installation Start-up All required functions available & working as specified Diabolical (e.g. power failures, corner cases, incorrect handling) Performance Usability Includes: Test cases you plan to run (numbered / named) Expected results Ordering of testing & dependencies Supporting materials needed Traceability to requirements

06/12/2007SE _6_12_Design.ppt8 Due Next Week System Test Plan draft for inspection Draft to Product Team by COB Tuesday SRS Inspection Quality Records High Level Design (SDS), Design Standards & Integration Test Plan Inspected & Baselined TSPi Planning forms Team & Engineer schedule updates Updated SUMP & SUMS forms

Backup Slides

06/12/2007SE _6_12_Design.ppt10 Inspections Estimating Defects Capture-ReCapture Example Catch 20 fish in lake, tag & release them Catch 25 more, 5 are tagged How many fish are in the lake? 5 out of 25 = 20 out of Total Population Total = ?

06/12/2007SE _6_12_Design.ppt11 Capture-ReCapture Formula Fishing example: 5 out of 25 = 20 out of Total C = # from both fishing tries (e.g. 5) A = # from first fishing try (e.g. 20) B = # from second fishing try (e.g. 25) So, C out of B = A out of Total C/B = A/Total Total = A*B/C

06/12/2007SE _6_12_Design.ppt12 Estimating Defects 2 Developer Case C = # from both tries = # found by both developers A = # from first try = # found by developer A B = # from second try = # found by developer B Total # defects = # A * # B / # both found Yield = # found / Total # defects expressed as percentage = 100 * (A*B-C) / (A*B/C) = 100 * (A*B-C)*C / A*B Humphrey 2 Developer Example: Two developers, A found 7, B found 5, common defects 3 Total estimated # defects = (7*5)/3 = 12 Yield = 9 / 12 = 75%

06/12/2007SE _6_12_Design.ppt13 Estimating Defects 3 Developer Example Three developers in an inspection identified 10 unique defects (# from 1 to 10). Harry found defects 1, 2, 3, 4 & 5 Chapin found defects 1, 2, 4, 6 & 7 Sue found defects 4, 6, 7, 8, 9 & 10 Estimate total # of defects in product prior to inspection. Estimate total inspection yield. Sue identified the most unique defects (3) = 6 identified Combine Harry’s & Chapin’s defects = 7 identified, 3 in common w/ Sue Total Product Defects = 6 * 7 / 3 = 14 Yield % = 100 * 10/14 = 71%

06/12/2007SE _6_12_Design.ppt14 Capture-ReCapture Assumptions & Cautions Population is homogeneous Population is randomly distributed Sample #s are reasonably large

06/12/2007SE _6_12_Design.ppt15 Probabilities Extra-Credit Problem Assuming birthdays are uniformly distributed across 365 days, what is the minimum number of people needed in a room for the probability of two people having the same birth date (day of year) to be greater than ½?