![Scripting (II)Scripting (II)
• You can check the exit code ofYou can check the exit code of
a program running from a shella program running from a shell
script:script:
– if [ $? –ne 0 ]; then … else … fiif [ $? –ne 0 ]; then … else … fi
• if the executable exitsif the executable exits
abnormally, the then clauseabnormally, the then clause
executes.executes.
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![Expect (Example)Expect (Example)
#!/usr/bin/expect#!/usr/bin/expect
set timeout 5set timeout 5
spawn ssh –x [lindex $argv 0] “ls /”spawn ssh –x [lindex $argv 0] “ls /”
expect {expect {
timout {puts “timeout”}timout {puts “timeout”}
eof {exit 0}eof {exit 0}
““continue connecting (yes/no)? ” {send “yes” }continue connecting (yes/no)? ” {send “yes” }
}}
expect {expect {
eof {exit 0}eof {exit 0}
}}
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Software testing (2) trainingin-mumbai
- 1. Software TestingSoftware Testing TechniquesTechniques Vibrant Technology & Computer 1
- 2. OutlineOutline • What is Testing?What is Testing? • Why Test?Why Test? • How To Test The Tests?How To Test The Tests? • Code Coverage (Peter)Code Coverage (Peter) • How To Decide What To Test?How To Decide What To Test? • Automation ToolsAutomation Tools • Writing Test CasesWriting Test Cases Vibrant Technology & Computer 2
- 3. What Is Testing?What Is Testing? • In this context – confirming correctIn this context – confirming correct behavior of a piece of software.behavior of a piece of software. Vibrant Technology & Computer 3
- 4. Why Test?Why Test? • We know what weWe know what we intendedintended thethe code to do – we need to confirm thatcode to do – we need to confirm that it does what we intended.it does what we intended. Vibrant Technology & Computer 4
- 5. How To Test Our Tests?How To Test Our Tests? • In other words: how can we be sureIn other words: how can we be sure our tests are:our tests are: – testing the right (relevant) “stuff”?testing the right (relevant) “stuff”? – testing “most” of the code and not justtesting “most” of the code and not just repeatedly testing the same code?repeatedly testing the same code? Vibrant Technology & Computer 5
- 6. Code CoverageCode Coverage • Take it away, Peter…Take it away, Peter… Vibrant Technology & Computer 6
- 7. How To Decide What ToHow To Decide What To Test?Test? Low-Level Classes Application Subsystems YourProgram Vibrant Technology & Computer 7
- 8. How To Decide (II)How To Decide (II) • The trick is drawing a line acrossThe trick is drawing a line across that triangle.that triangle. – Draw it too low and you have too manyDraw it too low and you have too many classes to test – and the tests aren’tclasses to test – and the tests aren’t meaningful.meaningful. – Draw it too high and a test failure leadsDraw it too high and a test failure leads you on a wild goose chase…you on a wild goose chase… • The bad news is – deciding where toThe bad news is – deciding where to draw that line is an art, not adraw that line is an art, not a science.science. Vibrant Technology & Computer 8
- 9. Automation ToolsAutomation Tools • How many times have you writtenHow many times have you written code and then sat in front of thecode and then sat in front of the keyboard running through testkeyboard running through test cases?cases? – How many times have you actuallyHow many times have you actually thought about test cases?thought about test cases? • The good news is that there is aThe good news is that there is a better way.better way. – And it’s never too late for a newAnd it’s never too late for a new beginning…beginning… Vibrant Technology & Computer 9
- 10. Automation To The RescueAutomation To The Rescue • A few key tools:A few key tools: – makemake • make running tests a part of your buildmake running tests a part of your build – scriptingscripting • if you can automate it, automate itif you can automate it, automate it – expectexpect • a powerful toola powerful tool Vibrant Technology & Computer 10
- 11. MakeMake • Add a test rule to your makefileAdd a test rule to your makefile – it should run all the tests– it should run all the tests you’ve written and log theiryou’ve written and log their results.results. • If they all pass, you’re done – ifIf they all pass, you’re done – if not, figure out why not.not, figure out why not. Vibrant Technology & Computer 11
- 12. ScriptingScripting • Imagine you have a bunch ofImagine you have a bunch of executables that test various partsexecutables that test various parts of your program.of your program. – We’ll talk about how they might be builtWe’ll talk about how they might be built shortly.shortly. • Imagine you’ve written a shell scriptImagine you’ve written a shell script to run them, one at a time.to run them, one at a time. • How do you know when one fails?How do you know when one fails? Vibrant Technology & Computer 12
- 13. Scripting (II)Scripting (II) • You can check the exit code ofYou can check the exit code of a program running from a shella program running from a shell script:script: – if [ $? –ne 0 ]; then … else … fiif [ $? –ne 0 ]; then … else … fi • if the executable exitsif the executable exits abnormally, the then clauseabnormally, the then clause executes.executes. Vibrant Technology & Computer 13
- 14. ExpectExpect • Written by Don Libes – an extensionWritten by Don Libes – an extension to Tclto Tcl – What, you’ve never heard of tcl?What, you’ve never heard of tcl? – That’s OK – there’s a python version asThat’s OK – there’s a python version as well.well. • If you’ve never heard of python, you shouldIf you’ve never heard of python, you should have attended our python seminar…have attended our python seminar… Vibrant Technology & Computer 14
- 15. Expect (II)Expect (II) • It’s be installed on the lab machinesIt’s be installed on the lab machines • Basic commands:Basic commands: • spawnspawn – run’s a new command under script control.run’s a new command under script control. • sendsend – provides input to the commandprovides input to the command • expectexpect – matches a pattern in the command outputmatches a pattern in the command output Vibrant Technology & Computer 15
- 16. Expect (Example)Expect (Example) #!/usr/bin/expect#!/usr/bin/expect set timeout 5set timeout 5 spawn ssh –x [lindex $argv 0] “ls /”spawn ssh –x [lindex $argv 0] “ls /” expect {expect { timout {puts “timeout”}timout {puts “timeout”} eof {exit 0}eof {exit 0} ““continue connecting (yes/no)? ” {send “yes” }continue connecting (yes/no)? ” {send “yes” } }} expect {expect { eof {exit 0}eof {exit 0} }} Vibrant Technology & Computer 16
- 17. Python ExpectPython Expect Pexpect –Pexpect – http://pexpect.sourceforge.nethttp://pexpect.sourceforge.net Good News: Provides *most* of expect’sGood News: Provides *most* of expect’s functionality from within python.functionality from within python. Bad News: it’s not installed on the labBad News: it’s not installed on the lab machines (yet?).machines (yet?). Vibrant Technology & Computer 17
- 18. Writing Test CasesWriting Test Cases • Write a simple executable that instantiatesWrite a simple executable that instantiates a class, and “drives” that instance.a class, and “drives” that instance. Vibrant Technology & Computer 18
- 19. Test Cases (Cont.)Test Cases (Cont.) • Imagine you have a linked list class…Imagine you have a linked list class… – If you wrote your own linked list class – andIf you wrote your own linked list class – and you’re working in C++ - you should have been inyou’re working in C++ - you should have been in our STL seminar.our STL seminar. • What should your test program test?What should your test program test? Vibrant Technology & Computer 19
- 20. Parting WordsParting Words • Be a skeptic – you, as the developer, areBe a skeptic – you, as the developer, are the only one who can crystal-box test yourthe only one who can crystal-box test your code.code. – Don’t test the easy cases – test the ones you’reDon’t test the easy cases – test the ones you’re not sure about.not sure about. – Don’t waste time testing the same thing moreDon’t waste time testing the same thing more than once – break input into “equivalencethan once – break input into “equivalence classes”classes” Vibrant Technology & Computer 20
- 21. Thank You…Thank You… Vibrant Technology & ComputerVibrant Technology & Computer Vashi,Navi MumbaiVashi,Navi Mumbai www.vibranttechnologies.comwww.vibranttechnologies.com ““100% job guarantee”100% job guarantee” Vibrant Technology & Computer 21