上浒文通大学 SHANGHAI JLAO TONG UNIVERSITY 11.Testing 六 漏 田 旺 SHANG 1日gG
11. Testing
上游充通大兽 Outline SHANGHAI JIAO TONG UNIVERSITY An Overview of Testing Testing Concepts Testing Activities Managing Testing Chapter 11 Software Engineering
Software Engineering Outline An Overview of Testing Testing Concepts Testing Activities Managing Testing Chapter 11
上游充通大粤 SHANGHAI JIAO TONG UNIVERSITY 1.An Overview of Testing Software Engineering
Software Engineering 1. An Overview of Testing
上海充通大学 SHANGHAI JIAO TONG UNIVERSITY 1.1 What is a computer bug? In 1947 Harvard University was operating a room-sized computer called the Mark Il. 。mechanical relays 数园2型 ·glowing vacuum tubes technicians program the computer by reconfiguring it Technicians had to change the occasional vacuum tube. A moth flew into the computer and was zapped by the high voltage when it landed on a relay. Hence,the first computer bug! Software Engineering
Software Engineering 1.1 What is a computer bug? In 1947 Harvard University was operating a room-sized computer called the Mark II. • mechanical relays • glowing vacuum tubes • technicians program the computer by reconfiguring it • Technicians had to change the occasional vacuum tube. A moth flew into the computer and was zapped by the high voltage when it landed on a relay. Hence, the first computer bug!
上大当.2 Adverse Effects of Faulty Software SHANGHAI JIAO TONG UNIVERSHY Communications:Loss or corruption of communication media,non delivery of data. Space Applications:Lost lives,launch delays. Defense and Warfare:Misidentification of friend or foe. Transportation:Deaths,delays,sudden acceleration,inability to brake. Safety-critical Applications:Death,injuries Electric Power:Death,injuries,power outages, long-term health hazards (radiation) Software Engineering
Software Engineering 1.2 Adverse Effects of Faulty Software Communications: Loss or corruption of communication media, non delivery of data. Space Applications: Lost lives, launch delays. Defense and Warfare: Misidentification of friend or foe. Transportation: Deaths, delays, sudden acceleration, inability to brake. Safety-critical Applications: Death, injuries. Electric Power: Death, injuries, power outages, long-term health hazards (radiation)
上游文通大警 SHANGHAI JIAO TONG UNIVERSITY Money Management:Fraud,violation of privacy,shutdown of stock exchanges and banks,negative interest rates. Control of Elections:Wrong results (intentional or non-intentional). Control of Jails:Technology-aided escape attempts and successes,accidental release of inmates,failures in software controlled locks. Law Enforcement:False arrests and imprisonments. Software Engineering
Software Engineering Money Management: Fraud, violation of privacy, shutdown of stock exchanges and banks, negative interest rates. Control of Elections: Wrong results (intentional or non-intentional). Control of Jails: Technology-aided escape attempts and successes, accidental release of inmates, failures in software controlled locks. Law Enforcement: False arrests and imprisonments
上游充通大学 SHANGHAI JIAO TONG UNIVERSITY 1.3 Bug in Space Code Project Mercury's FORTRAN code had the following fault: DO I=1.10 instead of...DO I=1,10 The fault was discovered in an analysis of why the software did not seem to generate results that were sufficiently accurate. The erroneous 1.10 would cause the loop to be executed exactly once！ Software Engineering
Software Engineering 1.3 Bug in Space Code Project Mercury ’ s FORTRAN code had the following fault: DO I=1.10 instead of ... DO I=1,10 The fault was discovered in an analysis of why the software did not seem to generate results that were sufficiently accurate. The erroneous 1.10 would cause the loop to be executed exactly once!
上降元大1.4 Military Aviation Problems SHANGHAI JIAO TONG UNIVERSITY An F-18 crashed because of a missing exception condition: if ..then ..without the else clause that was thought could not possibly arise. In simulation,an F-16 program bug caused the virtual plane to flip over whenever it crossed the equator,as a result of a missing minus sign to indicate south latitude. Software Engineering
Software Engineering 1.4 Military Aviation Problems An F-18 crashed because of a missing exception condition: if ... then ... without the else clause that was thought could not possibly arise. In simulation, an F-16 program bug caused the virtual plane to flip over whenever it crossed the equator, as a result of a missing minus sign to indicate south latitude
上降充通大学 1.5 Relative cost of bugs SHANGHAI JIAO TONG UNIVERSITY bugs found later cost more to fix" Cost to fix a bug increases exponentially (10x) i.e.,it increases tenfold as time increases E.g.,a bug found during specification costs $1 to fix. ..if found in design cost is $10 ..if found in code cost is $100 ..if found in released software cost is $1000 Software Engineering
Software Engineering 1.5 Relative cost of bugs “bugs found later cost more to fix ” Cost to fix a bug increases exponentially (10x) • i.e., it increases tenfold as time increases E.g., a bug found during specification costs $1 to fix. … if found in design cost is $10 … if found in code cost is $100 … if found in released software cost is $1000
上充大1.6 Fault Handling Techniques SHANGHAI JIAO TONG UNIVERSITY Fault Handling Fault Avoidance Fault Detection Fault Tolerance Design Atomic Modular Methodology Reviews Transactions Redundancy Verification Configuration Management Testing Debugging Unit Integration System Correctness Performance Testing Testing Testing Debugging Debugging Software Engineering
Software Engineering 1.6 Fault Handling Techniques Testing Fault Handling Fault Avoidance Fault Tolerance Fault Detection Debugging Unit Testing Integration Testing System Testing Verification Configuration Management Atomic Transactions Modular Redundancy Correctness Debugging Performance Debugging Reviews Design Methodology