Tcl Built-In Commands - Tcltest manual page

  NAME
    Tcltest - Test harness support code and utilities
  SYNOPSIS
    package require tcltest ?1.0?
    ::tcltest::test name desc ?constraint? script expectedAnswer
    ::tcltest::cleanupTests ?runningMultipleTests?
    ::tcltest::getMatchingTestFiles
    ::tcltest::loadTestedCommands
    ::tcltest::makeFile contents name
    ::tcltest::removeFile name
    ::tcltest::makeDirectory name
    ::tcltest::removeDirectory name
    ::tcltest::viewFile name
    ::tcltest::normalizeMsg msg
    ::tcltest::bytestring string
    ::tcltest::saveState
    ::tcltest::restoreState
    ::tcltest::threadReap
  DESCRIPTION
  COMMANDS
    ::tcltest::test name desc ?constraints? script expectedAnswer
    ::tcltest::cleanupTests ?runningMultipleTests?
    ::tcltest::getMatchingTestFiles
    ::tcltest::loadTestedCommands
    ::tcltest::makeFile contents name
    ::tcltest::removeFile name
    ::tcltest::makeDirectory name
    ::tcltest::removeDirectory name
    ::tcltest::viewFile file
    ::tcltest::normalizeMsg msg
    ::tcltest::bytestring string
    ::tcltest::saveState
    ::tcltest::threadReap
  TESTS
  TCLTEST NAMEPSACE VARIABLES
    ::tcltest::outputChannel
    ::tcltest::errorChannel
    ::tcltest::mainThread
    ::tcltest::originalEnv
    ::tcltest::workingDirectory
    ::tcltest::temporaryDirectory
    ::tcltest::testsDirectory
    ::tcltest::tcltest
    ::tcltest::loadScript
  TEST CONSTRAINTS
    unix
    pc
    nt
    95
    98
    mac
    unixOrPc
    macOrPc
    macOrUnix
    tempNotPc
    tempNotMac
    unixCrash
    pcCrash
    macCrash
    emptyTest
    knownBug
    nonPortable
    userInteraction
    interactive
    nonBlockFiles
    asyncPipeClose
    unixExecs
    hasIsoLocale
    root
    notRoot
    eformat
    stdio
  RUNNING TEST FILES
    -help
    -verbose <level>
    -match <matchList>
    -skip <skipList>
    -file <globPatternList>
    -notfile <globPatternList>
    -constraints <list>
    -limitconstraints <bool>
    -load <script>
    -loadfile <scriptfile>
    -tmpdir <directoryName>
    -testdir <directoryName>
    -preservecore <level>
      0
      1
      2
    -debug <debugLevel>
      0
      1
      2
      3
    -outfile <filename>
    -errfile <filename>
  TEST OUTPUT
  CONTENTS OF A TEST FILE
  SELECTING TESTS FOR EXECUTION WITHIN A FILE
  HOW TO CUSTOMIZE THE TEST HARNESS
    ::tcltest::PrintUsageInfoHook
    ::tcltest::processCmdLineArgsFlagHook
    ::tcltest::processCmdLineArgsHook flags
    ::tcltest::initConstraintsHook
    ::tcltest::cleanupTestsHook
  EXAMPLES
  KEYWORDS

### NAME

Tcltest - Test harness support code and utilities

### SYNOPSIS

package require tcltest ?1.0?
::tcltest::test name desc ?constraint? script expectedAnswer
::tcltest::cleanupTests ?runningMultipleTests?
::tcltest::getMatchingTestFiles
::tcltest::loadTestedCommands
::tcltest::makeFile contents name
::tcltest::removeFile name
::tcltest::makeDirectory name
::tcltest::removeDirectory name
::tcltest::viewFile name
::tcltest::normalizeMsg msg
::tcltest::bytestring string
::tcltest::saveState
::tcltest::restoreState
::tcltest::threadReap

### DESCRIPTION

The tcltest package provides the user with utility tools for writing and running tests in the Tcl test suite. It can also be used to create a customized test harness for an extension.

The Tcl test suite consists of multiple .test files, each of which contains multiple test cases. Each test case consists of a call to the test command, which specifies the name of test, a short description, any constraints that apply to the test case, the script to be run, and expected results. See the sections "Tests," "Test Constraints," and "Test Files and How to Run Them" for more details.

It is also possible to add to this test harness to create your own customized test harness implementation. For more defails, see the section "How to Customize the Test Harness".

This approach to testing was designed and initially implemented by Mary Ann May-Pumphrey of Sun Microsystems in the early 1990's. Many thanks to her for donating her work back to the public Tcl release.

### COMMANDS

::tcltest::test name desc ?constraints? script expectedAnswer
  The ::tcltest::test command runsscript and compares its result to expectedAnswer. It prints an error message if the two do not match. If ::tcltest::verbose contains "p" or "s", it also prints out a message if the test passed or was skipped. The test will be skipped if it doesn't match the ::tcltest::match variable, if it matches an element in ::tcltest::skip, or if one of the elements of constraint turns out not to be true. The ::tcltest::test command has no defined return values. See the "Writing a new test" section for more details on this command.

::tcltest::cleanupTests ?runningMultipleTests?
  This command should be called at the end of a test file. It prints statistics about the tests run and removes files that were created by ::tcltest::makeDirectory and ::tcltest::makeFile. Names of files and directories created outside of ::tcltest::makeFile and ::tcltest::makeDirectory and never deleted are printed to ::tcltest::outputChannel. This command also restores the original shell environment, as described by the ::env array. calledFromAll should be specified when ::tcltest::cleanupTests is called from an "all.tcl" file. Tcl files files are generally used to run multiple tests. For more details on how to run multiple tests, please see the section "Running test files". This proc has no defined return value.

::tcltest::getMatchingTestFiles
  This command is used when you want to run multiple test files. It returns the list of tests that should be sourced in an 'all.tcl' file. See the section "Running test files" for more information.

::tcltest::loadTestedCommands
  This command uses the script specified via the -load or -loadfile to load the commands checked by the test suite. Allowed to be empty, as the tested commands could have been compiled into the interpreter running the test suite.

::tcltest::makeFile contents name
  Create a file that will be automatically be removed by ::tcltest::cleanupTests at the end of a test file. This proc has no defined return value.

::tcltest::removeFile name
  Force the file referenced by name to be removed. This file name should be relative to ::tcltest::temporaryDirectory. This proc has no defined return values.

::tcltest::makeDirectory name
  Create a directory named name that will automatically be removed by ::tcltest::cleanupTests at the end of a test file. This proc has no defined return value.

::tcltest::removeDirectory name
  Force the directory referenced by name to be removed. This proc has no defined return value.

::tcltest::viewFile file
  Returns the contents of file.

::tcltest::normalizeMsg msg
  Remove extra newlines from msg.

::tcltest::bytestring string
  Construct a string that consists of the requested sequence of bytes, as opposed to a string of properly formed UTF-8 characters using the value supplied in string. This allows the tester to create denormalized or improperly formed strings to pass to C procedures that are supposed to accept strings with embedded NULL types and confirm that a string result has a certain pattern of bytes.

::tcltest::saveState
  ::tcltest::restoreState Save and restore the procedure and global variable names. A test file might contain calls to ::tcltest::saveState and ::tcltest:restoreState if it creates or deletes global variables or procs.

::tcltest::threadReap
  ::tcltest::threadReap only works if testthread is defined, generally by compiling tcltest. If testthread is defined, ::tcltest::threadReap kills all threads except for the main thread. It gets the ID of the main thread by calling testthread names during initialization. This value is stored in ::tcltest::mainThread. ::tcltest::threadReap returns the number of existing threads at completion.

### TESTS

The test procedure runs a test script and prints an error message if the script's result does not match the expected result. The following is the spec for the test command:

    test <name> <description> ?<constraint>? <script> <expectedAnswer>

The <name> argument should follow the pattern:

    <target>-<majorNum>.<minorNum>

For white-box (regression) tests, the target should be the name of the C function or Tcl procedure being tested. For black-box tests, the target should be the name of the feature being tested. Related tests should share a major number.

The <description> argument is a short textual description of the test, to help humans understand what it tests. The name of a Tcl or C function being tested should be included for regression tests. If the test case exists to reproduce a bug, include the bug ID in the description.

The optional <constraints> argument can be list of one or more keywords or an expression. If the <constraints> argument consists of keywords, each of these keywords must be the name of an element in the array ::tcltest::testConstraints. If any of these elements is false or does not exist, the test is skipped. If the <constraints> argument consists of an expression, that expression is evaluated. If the expression evaluates to true, then the test is run.

Add appropriate constraints (e.g., unixOnly) to any tests that should not always be run. For example, a test that should only be run on Unix should look like the following:

    test getAttribute-1.1 {testing file permissions} {unixOnly} {
        lindex [file attributes foo.tcl] 5
    } {00644}

An example of a test that contains an expression:

    test unixNotfy-1.1 {Tcl_DeleteFileHandler} {unixOnly && !testthread} {
        catch {vwait x}
        set f [open foo w]
        fileevent $f writable {set x 1}
        vwait x
        close $f
        list [catch {vwait x} msg] $msg
    } {1 {can't wait for variable "x":  would wait forever}}

See the "Test Constraints" section for a list of built-in constraints and information on how to add your own constraints.

The <script> argument contains the script to run to carry out the test. It must return a result that can be checked for correctness. If your script requires that a file be created on the fly, please use the ::tcltest::makeFile procedure. If your test requires that a small file (<50 lines) be checked in, please consider creating the file on the fly using the ::tcltest::makeFile procedure. Files created by the ::tcltest::makeFile procedure will automatically be removed by the ::tcltest::cleanupTests call at the end of each test file.

The <expectedAnswer> argument will be compared against the result of evaluating the <script> argument. If they match, the test passes, otherwise the test fails.

### TCLTEST NAMEPSACE VARIABLES

The following variables are also defined in the tcltest namespace and can be used by tests:

::tcltest::outputChannel
  output file ID - defaults to stdout and can be specified using -outfile on the command line. Any test that prints test related output should send that output to ::tcltest::outputChannel rather than letting that output default to stdout.

::tcltest::errorChannel
  error file ID - defaults to stderr and can be specified using -errfile on the command line. Any test that prints error messages should send that output to ::tcltest::errorChannel rather than printing directly to stderr.

::tcltest::mainThread
  main thread ID - defaults to 1. This is the only thread that is not killed by ::tcltest::threadReap and is set according to the return value of testthread names at initialization.

::tcltest::originalEnv
  copy of the global "env" array at the beginning of the test run. This array is used to restore the "env" array to its original state when ::tcltest::cleanupTests is called.

::tcltest::workingDirectory
  the directory in which the test suite was launched.

::tcltest::temporaryDirectory
  the output directory - defaults to ::tcltest::workingDirectory and can be specified using -tmpdir on the command line.

::tcltest::testsDirectory
  where the tests reside - defaults to ::tcltest::workingDirectory if the script cannot determine where the tests directory is located. It is possible to change the default by specifying -testdir on the commandline. This variable should be explicitly set if tests are being run from an all.tcl file.

::tcltest::tcltest
  the name of the executable used to invoke the test suite.

::tcltest::loadScript
  The script executed loadTestedCommands. Specified either by -load or -loadfile.

### TEST CONSTRAINTS

Constraints are used to determine whether a test should be skipped. Each constraint is stored as an index in the array ::tcltest::testConstraints. For example, the unixOnly constraint is defined as the following:

    set ::tcltest::testConstraints(unixOnly) \
        [string equal $tcl_platform(platform) "unix"]

If a test is constrained by "unixOnly", then it will only be run if the value of ::tcltest::testConstraints(unixOnly) is true. Several constraints are defined in the tcltest package. To add file- or test-specific constraints, you can set the desired index of the ::tcltest::testsConstraints array in your own test file.

The following is a list of constraints defined in the tcltest package:

unix
  test can only be run on any UNIX platform

pc
  test can only be run on any Windows platform

nt
  test can only be run on any Windows NT platform

95
  test can only be run on any Windows 95 platform

98
  test can only be run on any Windows 98 platform

mac
  test can only be run on any Mac platform

unixOrPc
  test can only be run on a UNIX or PC platform

macOrPc
  test can only be run on a Mac or PC platform

macOrUnix
  test can only be run on a Mac or UNIX platform

tempNotPc
  test can not be run on Windows. This flag is used to temporarily disable a test.

tempNotMac
  test can not be run on a Mac. This flag is used to temporarily disable a test.

unixCrash
  test crashes if it's run on UNIX. This flag is used to temporarily disable a test.

pcCrash
  test crashes if it's run on Windows. This flag is used to temporarily disable a test.

macCrash
  test crashes if it's run on a Mac. This flag is used to temporarily disable a test.

emptyTest
  test is empty, and so not worth running, but it remains as a place-holder for a test to be written in the future. This constraint always causes tests to be skipped.

knownBug
  test is known to fail and the bug is not yet fixed. This constraint always causes tests to be skipped unless the user specifies otherwise. See the "Introduction" section for more details.

nonPortable
  test can only be run in the master Tcl/Tk development environment. Some tests are inherently non-portable because they depend on things like word length, file system configuration, window manager, etc. These tests are only run in the main Tcl development directory where the configuration is well known. This constraint always causes tests to be skipped unless the user specifies otherwise.

userInteraction
  test requires interaction from the user. This constraint always causes tests to be skipped unless the user specifies otherwise.

interactive
  test can only be run in if the interpreter is in interactive mode, that is the global tcl_interactive variable is set to 1.

nonBlockFiles
  test can only be run if platform supports setting files into nonblocking mode

asyncPipeClose
  test can only be run if platform supports async flush and async close on a pipe

unixExecs
  test can only be run if this machine has commands such as 'cat', 'echo', etc. available.

hasIsoLocale
  test can only be run if can switch to an ISO locale

root
  test can only run if Unix user is root

notRoot
  test can only run if Unix user is not root

eformat
  test can only run if app has a working version of sprintf with respect to the "e" format of floating-point numbers.

stdio
  test can only be run if the current app can be spawned via a pipe

### RUNNING TEST FILES

Use the following command to run a test file that uses package tcltest:

    <shell> <testFile> ?<option> ?<value>?? ...

Command line options include (tcltest namespace variables that correspond to each flag are listed at the end of each flag description in parenthesis):

-help
  display usage information.

-verbose <level>
  set the level of verbosity to a substring of "bps". See the "Test output" section for an explanation of this option. (::tcltest::verbose)

-match <matchList>
  only run tests that match one or more of the glob patterns in <matchList>. (::tcltest::match)

-skip <skipList>
  do not run tests that match one or more of the glob patterns in <skipList>. (::tcltest::skip)

-file <globPatternList>
  only source test files that match any of the items in <globPatternList> relative to ::tcltest::testsDirectory. This option only makes sense if you are running tests using "all.tcl" as the <testFile> instead of running single test files directly. (::tcltest::matchFiles)

-notfile <globPatternList>
  source files except for those that match any of the items in <globPatternList> relative to ::tcltest::testsDirectory. This option only makes sense if you are running tests using "all.tcl" as the <testFile> instead of running single test files directly. (::tcltest::skipFiles)

-constraints <list>
  tests with any constraints in <list> will not be skipped. Note that elements of <list> must exactly match the existing constraints. This is useful if you want to make sure that tests with a particular constraint are run (for example, if the tester wants to run all tests with the knownBug constraint). (::tcltest::testConstraints(constraintName))

-limitconstraints <bool>
  If the argument to this flag is 1, the test harness limits test runs to those tests that match the constraints listed by the -constraints flag. Use of this flag requires use of the -constraints flag. The default value for this flag is 0 (false). This is useful if you want to run only those tests that match the constraints listed using the -constraints option. A tester might want to do this if he were interested in running only those tests that are constrained to be unixOnly and no other tests. (::tcltest::limitConstraints)

-load <script>
  will use the specified script to load the commands under test (::tcltest::loadTestedCommands). The default is the empty script. See -loadfile below too. (::tcltest::loadScript)

-loadfile <scriptfile>
  will use the contents of the named file to load the commands under test (::tcltest::loadTestedCommands). See -load above too. The default is the empty script. (::tcltest::loadScript)

-tmpdir <directoryName>
  put any temporary files (created with ::tcltest::makeFile and ::tcltest::makeDirectory) into the named directory. The default location is ::tcltest::workingDirectory. (::tcltest::temporaryDirectory)

-testdir <directoryName>
  search the test suite to execute in the named directory. The default location is ::tcltest::workingDirectory. (::tcltest::testsDirectory)

-preservecore <level>
  check for core files. This flag is used to determine how much checking should be done for core files. The default value for level is 0. Levels are defined as:

  0
    No checking - do not check for core files at the end of each test command, but do check for them whenever ::tcltest::cleanupTests is called from an all.tcl file.

  1
    Check for core files at the end of each test command and whenever ::tcltest::cleanupTests is called from all.tcl.

  2
    Check for core files at the end of all test commands and whenever ::tcltest::cleanupTests is called from all.tcl. Save any core files produced in ::tcltest::temporaryDirectory.

  (::tcltest::preserveCore)

-debug <debugLevel>
  print debug information to stdout. This is used to debug code in the test harness. The default debug level is 0. Levels are defined as:

  0
    Do not display any debug information.

  1
    Display information regarding whether a test is skipped because it doesn't match any of the tests that were specified using -match or ::tcltest::match (userSpecifiedNonMatch) or matches any of the tests specified by -skip or ::tcltest::skip (userSpecifiedSkip).

  2
    Display the flag array parsed by the command line processor, the contents of the ::env array, and all user-defined variables that exist in the current namespace as they are used.

  3
    Display information regarding what individual procs in the test harness are doing.

  (::tcltest::debug)

-outfile <filename>
  print output generated by the tcltest package to the named file. This defaults to stdout. Note that debug output always goes to stdout, regardless of this flag's setting. (::tcltest::outputChannel)

-errfile <filename>
  print errors generated by the tcltest package to the named file. This defaults to stderr. (::tcltest::errorChannel)

A second way to run tets is to start up a shell, load the tcltest package, and then source an appropriate test file or use the test command. To use the options in interactive mode, set their corresponding tcltest namespace variables after loading the package.

See "Test Constraints" for all built-in constraint names that can be used in the ::tcltest::testConstraints array. See "Tcltest namespace variables" for details on other variables defined in the tcltest namespace.

A final way to run tests would be to specify which test files to run within an all.tcl (or otherwise named) file. This is the approach used by the Tcl test suite. This file loads the tcltest package, sets the location of the test directory (::tcltest::testsDirectory), determines which test files to run, sources each of these files, calls ::tcltest::cleanupTests and then exits.

A more elaborate all.tcl file might do some pre- and post-processing before sourcing each .test file, use separate interpreters for each file, or handle complex directory structures. For an example of an all.tcl file, please see the "Examples" section of this document.

### TEST OUTPUT

After all specified test files are run, the number of tests passed, skipped, and failed is printed to ::tcltest::outputChannel. Aside from this statistical information, output can be controlled on a per-test basis by the ::tcltest::verbose variable.

::tcltest::verbose can be set to any substring or permutation of "bps". In the string "bps", the 'b' stands for a test's "body", the 'p' stands for "passed" tests, and the 's' stands for "skipped" tests. The default value of ::tcltest::verbose is "b". If 'b' is present, then the entire body of the test is printed for each failed test, otherwise only the test's name, desired output, and actual output, are printed for each failed test. If 'p' is present, then a line is printed for each passed test, otherwise no line is printed for passed tests. If 's' is present, then a line (containing the consraints that cause the test to be skipped) is printed for each skipped test, otherwise no line is printed for skipped tests.

You can set ::tcltest::verbose either interactively (after the tcltest package has been loaded) or by using the command line argument -verbose, for example:

    tclsh socket.test -verbose bps

### CONTENTS OF A TEST FILE

Test files should begin by loading the tcltest package:

    if {[lsearch [namespace children] ::tcltest] == -1} {
        package require tcltest
        namespace import ::tcltest::*
    }

Test files should end by cleaning up after themselves and calling ::tcltest::cleanupTests. The ::tcltest::cleanupTests procedure prints statistics about the number of tests that passed, skipped, and failed, and removes all files that were created using the ::tcltest::makeFile and ::tcltest::makeDirectory procedures.

    # Remove files created by these tests
    # Change to original working directory
    # Unset global arrays
    ::tcltest::cleanupTests
    return

When naming test files, file names should end with a .test extension. The names of test files that contain regression (or glass-box) tests should correspond to the Tcl or C code file that they are testing. For example, the test file for the C file "tclCmdAH.c" is "cmdAH.test". Test files that contain black-box tests should match the pattern "*_bb.test".

### SELECTING TESTS FOR EXECUTION WITHIN A FILE

Normally, all the tests in a file are run whenever the file is sourced. An individual test will be skipped if one of the following conditions is met:

[1]
  the name of the tests does not match (using glob style matching) one or more elements in the ::tcltest::match variable

[2]
  the name of the tests matches (using glob style matching) one or more elements in the ::tcltest::skip variable

[3]
  the constraints argument to the ::tcltest::test call, if given, contains one or more false elements.

You can set ::tcltest::match and/or ::tcltest::skip either interactively (after the tcltest package has been sourced), or by using the command line arguments -match and -skip, for example:

    tclsh info.test -match '*-5.* *-7.*' -skip '*-7.1*'

Be sure to use the proper quoting convention so that your shell does not perform the glob substitution on the match or skip patterns you specify.

Predefined constraints (e.g. knownBug and nonPortable) can be overridden either interactively (after the tcltest package has been sourced) by setting the proper ::tcltest::testConstraints(constraint) variable or by using the -constraints command line option with the name of the constraint in the argument. The following example shows how to run tests that are constrained by the knownBug and nonPortable restrictions:

    tclsh all.tcl -constraints "knownBug nonPortable"

See the "Constraints" package for information about using built-in constraints and adding new ones.

### HOW TO CUSTOMIZE THE TEST HARNESS

To create your own custom test harness, create a .tcl file that contains your namespace. Within this file, require package tcltest. Commands that can be redefined to customize the test harness include:

::tcltest::PrintUsageInfoHook
  print additional usage information specific to your situation.

::tcltest::processCmdLineArgsFlagHook
  tell the test harness about additional flags that you want it to understand.

::tcltest::processCmdLineArgsHook flags
  process the additional flags that you told the harness about in ::tcltest::processCmdLineArgsFlagHook.

::tcltest::initConstraintsHook
  used to add additional built-in constraints to those already defined by tcltest.

::tcltest::cleanupTestsHook
  do additional cleanup

To add new flags to your customized test harness, redefine ::tcltest::processCmdLineArgsAddFlagHook to define additional flags to be parsed and ::tcltest::processCmdLineArgsHook to actually process them. For example:

    proc ::tcltest::processCmdLineArgsAddFlagHook {} {
        return [list -flag1 -flag2]
    }

    proc ::tcltest::processCmdLineArgsHook {flagArray} {
        array set flag $flagArray

        if {[info exists flag(-flag1)]} {
            # Handle flag1
        }

        if {[info exists flag(-flag2)]} {
            # Handle flag2
        }

        return
    }

You may also want to add usage information for these flags. This information would be displayed whenever the user specifies -help. To define additional usage information, define your own ::tcltest::PrintUsageInfoHook proc. Within this proc, you should print out additional usage information for any flags that you've implemented.

To add new built-in constraints to the test harness, define your own version of ::tcltest::initConstraintsHook. Within your proc, you can add to the ::tcltest::testConstraints array. For example:

    proc ::tcltest::initConstraintsHook {} {
        set ::tcltest::testConstraints(win95Or98) \
                [expr {$::tcltest::testConstraints(95) || \
                $::tcltest::testConstraints(98)}]
    }

Finally, if you want to add additional cleanup code to your harness you can define your own ::tcltest::cleanupTestsHook. For example:

    proc ::tcltest::cleanupTestsHook {} {
        # Add your cleanup code here
    }

### EXAMPLES

[1]
  A simple test file (foo.test)

      if {[lsearch [namespace children] ::tcltest] == -1} {
          package require tcltest
          namespace import ::tcltest::*
      }

      test foo-1.1 {save 1 in variable name foo} {} {
          set foo 1
      } {1}

      ::tcltest::cleanupTests
      return

[2]
  A simple all.tcl

      if {[lsearch [namespace children] ::tcltest] == -1} {
          package require tcltest
          namespace import ::tcltest::*
      }

      set ::tcltest::testSingleFile false
      set ::tcltest::testsDirectory [file dir [info script]]

      foreach file [::tcltest::getMatchingTestFiles] {
          if {[catch {source $file} msg]} {
              puts stdout $msg
          }
      }

      ::tclttest::cleanupTests 1
      return

[3]
  Running a single test

      tclsh foo.test

[4]
  Running multiple tests

      tclsh all.tcl -file 'foo*.test' -notfile 'foo2.test'

### KEYWORDS

test, test harness, test suite

    Copyright © 1990-1994 The Regents of the University of California
    Copyright © 1994-1997 Sun Microsystems, Inc.
    Copyright © 1998-1999 Scriptics Corporation
    Copyright © 1995-1997 Roger E. Critchlow Jr.