Scripts on My Tool Belt

1
Scripts on My Tool Belt

• Danny R. Faught
• Tejas Software Consulting
• www.tejasconsulting.com
• Software Test Automation Conference
• Fall 2001

2
My aim for this talk

• Convince you that test automation is more than
  automating test execution
• Show some examples of the kinds of things Ive
  accomplished with scripting languages, using
  simplified code samples
• Make you aware of three different scripting
  languages (shells, perl, and expect)

3
Why scripting?

• Scripting languages are easier to learn than
  compiled languages.
• Scripts get more done in less code and less
  coding time than compiled languages.
• This can make the difference between using
  automation and not trying at all.

4
Part 1 Shell Scripting

• Shell scripts allow you to automate system
  commands, and gives you some rudimentary control
  logic (variables, looping, etc.).
• Shells were developed for Unix, but are also
  available on Windows and other platforms.
• There are several shells to choose from your
  login shell may not be the best choice.
• For our examples, well use the bash shell.

5
Shell script example simplemon

• A simple script to monitor the basic health of a
  system over the network
• Designed to run on Windows in the cygwin
  environment
• These commands are external to bash ping, grep,
  echo, rm, sleep, even true and test
• Uses the open source Blat program to send email

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simplemon

• 1 !/bin/bash
• 2 target127.0.0.1
• 3 notifymyaddr_at_myhost.com
• 4 while true
• 5 do
• 6 ping -n 1 target simplemon.out 21
• 7 grep -q "Reply from" simplemon.out
• 8 ping_status?
• 9 if test ping_status ! 0
• 10 then
• 11 echo PING STATUS ping_status
  simplemon.out
• 12 blat simplemon.out -s "simplemon
  status" -t "notify"
• 13 rm simplemon.out
• 14 exit 1
• 15 fi
• 16 sleep 30
• 17 done

7
Shell script portability

• What if you wanted to run on Unix as well?
• Shell script portability is difficult because the
  real work is spread across many external
  programs.
• To make the script portable, we use uname to
  check the OS, and add functions to do the ping
  and to send mail.

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Portable mail function

• 1 osuname -s
• 2 ...
• 3 function send_mail
• 4 file1
• 5 subject2
• 6 to3
• 7 if test "os" "CYGWIN_NT-4.0"
• 8 then
• 9 blat file -s "subject" -t "to"
• 10 else
• 11 mailx -s "subject" "to"
• 12 fi
• 13

9
Portable ping function

• 1 function one_ping
• 2 host1
• 3 if test "os" CYGWIN_NT-4.0
• 4 then
• 5 ping -n 1 host ping.out
• 6 cat ping.out
• 7 grep -q "Reply from" ping.out
• 8 status?
• 9 rm ping.out
• 10 test status 0
• 11 elif test "os" HP-UX
• 12 then
• 13 outputping host 64 1
• 14 echo output
• 15 echo output grep -q " 0 packet
  loss"
• 16 else ...

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Part 2 Perl

• Perl is a general-purpose scripting language that
  runs on a very wide variety of platforms.
• Youll either love its power, or hate its
  complexity.

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Test dataa perl one-liner

• perl -e 'print \0" x 1000000' file
• Quickly generates a file of a million null
  characters.
• Very useful as an input file, and likely to break
  any software that tries to read it.
• Its very easy to recreate the file with
  different contents or a different size to isolate
  a failure.
• (this example uses bash command line syntax)

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Another one-liner

• perl -e print ((A" x 72 . \n)
• x 10000)' file
• Uses a different character and a more reasonable
  line size.
• This example creates a file with 10,000 lines,
  each of which consists of a string of 72 A
  characters.

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The Sandwich Model

• Scripts may be used at all three levels.
• The bottom and top of the sandwich often uses
  customized code, when its difficult to add
  features to the general-purpose harness

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Front end for a commercial tool

• Say were using the eValid tool for web testing.
  Errors show up in the log like this (this is a
  single long line)
• 2001/06/25 154949 6 3 15 Project Group Test2
  ERROR 3035 441 - Document not found
  http//tejasconsulting.com/badlink 404
• We want a front end that can run an eValid test,
  report back whether it failed, and summarize the
  failure.
• With further enhancement, it should run large
  sets of tests and summarize the results.

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evrun script

• 1 !/usr/bin/perl -w
• 2 testname shift _at_ARGV or die "must specify
  test name\n"
• 3 system "eValid -B testname.evs -CK"
• 4 status ?
• 5 path "c/Program Files/Software
  Research/eValid/Program/Project/Group/"
• 6 open LOG, "path/testname-M.log" or die
  "open !"
• 7 my err 0
• (continued)

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evrun, continued

• 8 while ()
• 9 if (/ERROR/ ! /Command completed/)
• 10 s/.ERROR\s\d\s\d\s\S\s(.)/1/
• 11 print
• 12 err
• 13
• 14
• 15 close LOG
• 16 print "eValid status status\n"
• 17 print "Error count err\n"
• 18 exit err

17
evrun output

• C\evevrun Test2
• Document not found http//tejasconsulting.com/bad
  link 404
• eValid status 16384
• Error count 1
• Note there are other ways that the test can
  fail, such as a timeout. Further analysis of the
  possible log file entries would be needed to make
  this script reliable.

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Part 3 expect

• Expect is a scripting language for automating
  interactive command-line interfaces.
• Based on tcl (tool command language)
• Also the basis for the freeware test harness
  DejaGnu

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Examplethe crypt command

• You dont need expect for simple commands just
  write to standard input.
• Commands like crypt and passwd on Unix,
  however, read directly from the terminal.
• Expect provides a pseudo-terminal that allows you
  to automate these commands.

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crypt.exp

• 1 !/usr/bin/expect -f
• 2 spawn -nottycopy /bin/sh -c "crypt crypt.out"
• 3 expect
• 4 timeout send_error "TIMEOUT!\n" exit
  -1
• 5 eof send_error "EOF!\n" exit -1
• 6 "Enter key"
• 7
• 8 send "this_is_the_key\r"
• 9 expect
• 10 timeout send_error "TIMEOUT!\n" exit
  -1
• 11 eof
• 12
• 13 set status wait
• 14 exit lindex status 3

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Windows example ftp

• 1 !/usr/bin/expect -f
• 2 expect_before
• 3 timeout send_error "TIMEOUT!\n" exit -1
  
• 4
• 5 spawn c/winnt2/system32/ftp.exe myftphost.com
• 6 expect User
• 7 expect ""
• 8 send faught\r"
• 9 expect "Password"
• 10 send pw\r"
• 11 expect "ftp"
• 12 send "ls\r"
• 13 expect "ftp"
• 14 send "quit\r"
• 15 expect "Goodbye."

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Output from ftp script

• c\ ftp.exp
• spawn c/winnt2/system32/ftp.exe myftphost.com
• Connected to myftphost.com.
• 220 myftphost.com FTP server (Version 1.7.109.12)
  ready.
• User (myftphost(none)) faught
• 331 Password required for faught.
• Password
• 230 User faught logged in.
• ftp ls
• 200 PORT command successful.
• 150 Opening ASCII mode data connection for file
  list.
• file1
• file2
• 226 Transfer complete.
• 848 bytes received in 0.33 seconds (2.56
  Kbytes/sec)
• ftp quit
• 221 Goodbye.

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Web Resources

• Cygwin www.cygwin.com (for bash install)
• Bash cnswww.cns.cwru.edu/chet/bash/bashtop.html
• Blat http//pages.infinit.net/che/blat/blat.html
• Perl www.perl.com (and many others)
• Expect http//expect.nist.gov/
• Windows NT port of expect http//bmrc.berkeley.ed
  u/people/chaffee/expectnt.html

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Books and Articles

• Learning the bash Shell, 2nd Edition, ISBN
  1-56592-347-2
• Programming Perl, 3rd Edition, ISBN 0-596-00027-8
  (and others from OReilly)
• Exploring Expect, ISBN 1-56592-090-2
• Some old Software QA magazine articles at
  www.tejasconsulting.com (use at your own risk)
  The Shell Game, Testing Interactive Programs,
  and Using Perl Scripts
• Hey Vendors, Give Us Real Scripting Languages,
  by Bret Pettichord, posted on StickyMinds.com

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Wrap-up

• Some knowledge of at least one scripting language
  can make a tester much more productive!
• Most scripting languages were designed for Unix,
  but can be made to work under Windows and other
  systems.
• For annotated versions of the scripts in this
  presentation, see www.tejasconsulting.com/resourc
  es/toolbelt/
• Thanks for listening!-Danny (faught_at_tejasconsulti
  ng.com)