Test::Cmd::Common(3)

NAME
Test::Cmd::Common - module for common Test::Cmd error handling

SYNOPSIS
  use Test::Cmd::Common;

  $test = Test::Cmd::Common->new(string => 'functionality being tested',
                        prog => 'program_under_test',
                        );

  $test->run(chdir => 'subdir', fail => '$? != 0',
                flags => '-x', targets => '.',
                stdout => <<_EOF_, stderr => <<_EOF_);
  expected standard output
  _EOF_
  expected error output
  _EOF_

  $test->subdir('subdir', ...);

  $test->read(\$contents, 'file');
  $test->read(\@lines, 'file');

  $test->write('file', <<_EOF_);
  contents of the file
  _EOF_

  $test->file_matches();

  $test->must_exist('file', ['subdir', 'file'], ...);

  $test->must_not_exist('file', ['subdir', 'file'], ...);

  $test->copy('src_file', 'dst_file');

  $test->chmod($mode, 'file', ...);

  $test->sleep;
  $test->sleep($seconds);

  $test->touch('file', ...);

  $test->unlink('file', ...);

DESCRIPTION
The "Test::Cmd::Common" module provides a simple, high-level interface for writing tests of executable commands and scripts, especially commands and scripts that interact with the file system. All methods throw exceptions and exit on failure. This makes it unnecessary to add explicit checks for return values, making the test scripts themselves simpler to write and easier to read.

The "Test::Cmd::Common" class is a subclass of Test::Cmd. In essence, "Test::Cmd::Common" is a wrapper that treats common Test::Cmd error conditions as exceptions that terminate the test. You can use "Test::Cmd::Common" directly, or subclass it for your program and add additional (or override) methods to tailor it to your program's specific needs. Alternatively, "Test::Cmd::Common" serves as a useful example of how to define your own Test::Cmd subclass.

The "Test::Cmd::Common" module provides the following importable variables:

$_exe
    The executable file suffix. This value is normally available as $Config{_exe} in Perl version 5.005 and later. The "Test::Cmd::Common" module figures it out via other means in earlier versions.

$_o The object file suffix. This value is normally available from $Config{_o} in Perl version 5.005 and later. The "Test::Cmd::Common" module figures it out via other means in earlier versions.

$_a The library file suffix. This value is normally available from as $Config{_a} in Perl version 5.005 and later. The "Test::Cmd::Common" module figures it out via other means in earlier versions.

$_so
    The shared library file suffix. This value is normally available as $Config{_so} in Perl version 5.005 and later. The "Test::Cmd::Common" module figures it out via other means in earlier versions.

$_is_win32
    A Boolean value that reflects whether the current platform is a Win32 system.

METHODS

"new"
    Creates a new test environment object. Any arguments are keyword-value pairs that are passed through to the construct method for the base class from which we inherit our methods (that is, the Test::Cmd class). In the normal case, this should be the program to be tested and a description of the functionality being tested:

        $test = Test::Cmd::Common->new(prog => 'my_program',
                                       string => 'cool new feature');

    By default, methods that match actual versus expected output (the "run", and "file_matches" methods) use an exact match. Tests that require regular expression matches can specify this on initialization of the test environment:

        $test = Test::Cmd::Common->new(prog => 'my_program',
                                       string => 'cool new feature',
                                       match_sub => \&Test::Cmd::diff_regex);

    or by executing the following after initialization of the test environment:

        $test->match_sub(\&Test::Cmd::diff_regex);

    Creates a temporary working directory for the test environment and changes directory to it.

    Exits NO RESULT if the object can not be created, the temporary working directory can not be created, or the current directory cannot be changed to the temporary working directory.

"run"
    Runs the program under test, checking that the test succeeded. Arguments are keyword-value pairs that affect the manner in which the program is executed or the results are evaluated.

        chdir => 'subdir'
        fail => 'failure condition' # default is '$? != 0'
        flags => 'Cons flags'
        stderr => 'expected error output'
        stdout => 'expected standard output'
        targets => 'targets to build'

    The test fails if:

      --  The specified failure condition is met.  The default failure
          condition is '$? != 0', i.e. the program exits unsuccesfully.
          A not-uncommon alternative is:

              $test->run(fail => '$? == 0');        # expect failure

          when testing how the program handles errors.

      --  Actual standard output does not match expected standard output
          (if any).  The expected standard output is an array of lines
          or a scalar which will be split on newlines.

      --  Actual error output does not match expected error output (if
          any).  The expected error output is an array of lines or a
          scalar which will be split on newlines.

          This method will test for NO error output by default if no
          expected error output is specified (unlike standard output).
          The error output test may be explicitly suppressed by
          specifying undef as the "expected" error output:

              $test->run(stderr => undef);

    By default, this method performs an exact match of actual vs. expected standard output or error output:

        $test->run(stdout => <<_EOF_, stderr => _EOF_);
        An expected STDOUT line, which must be matched exactly.
        _EOF_
        One or more expected STDERR lines,
        which must be matched exactly.
        _EOF_

    Tests that require regular expression matches should be executed using a test environment that calls the "match_sub" method as follows:

        $test->match_sub(\&Test::Cmd::diff_regex);

        $test->run(stdout => <<_EOF_, stderr => _EOF_);
        An expected (STDOUT|standard output) line\.
        _EOF_
        One or more expected (STDERR|error output) lines,
        which may contain (regexes|regular expressions)\.
        _EOF_

"subdir"
    Creates one or more subdirectories in the temporary working directory. Exits NO RESULT if the number of subdirectories actually created does not match the number expected. For compatibility with its superclass method, returns the number of subdirectories actually created.

"read"
    Reads the contents of a file, depositing the contents in the destination referred to by the first argument (a scalar or array reference). If the file name is not an absolute path name, it is relative to the temporary working directory. Exits NO RESULT if the file could not be read for any reason. For compatibility with its superclass method, returns TRUE on success.

"write"
    Writes a file with the specified contents. If the file name is not an absolute path name, it is relative to the temporary working directory. Exits NO RESULT if there were any errors writing the file. For compatibility with its superclass method, returns TRUE on success.

        $test->write('file', <<_EOF_);
        contents of the file
        _EOF_

"file_matches"
    Matches the contents of the specified file (first argument) against the expected contents. The expected contents are an array of lines or a scalar which will be split on newlines. By default, each expected line must match exactly its corresponding line in the file:

        $test->file_matches('file', <<_EOF_);
        Line #1.
        Line #2.
        _EOF_

    Tests that require regular expression matches should be executed using a test environment that calls the "match_sub" method as follows:

        $test->match_sub(\&Test::Cmd::diff_regex);

        $test->file_matches('file', <<_EOF_);
        The (1st|first) line\.
        The (2nd|second) line\.
        _EOF_

"must_exist"
    Ensures that the specified files must exist. Files may be specified as an array reference of directory components, in which case the pathname will be constructed by concatenating them. Exits FAILED if any of the files does not exist.

"must_not_exist"
    Ensures that the specified files must not exist. Files may be specified as an array reference of directory components, in which case the pathname will be constructed by concatenating them. Exits FAILED if any of the files exists.

"copy"
    Copies a file from the source (first argument) to the destination (second argument). Exits NO RESULT if the file could not be copied for any reason.

"chmod"
    Changes the permissions of a list of files to the specified mode (first argument). Exits NO RESULT if any file could not be changed for any reason.

"sleep"
    Sleeps at least the specified number of seconds. If no number is specified, sleeps at least a minimum number of seconds necessary to advance file time stamps on the current system. Sleeping more seconds is all right. Exits NO RESULT if the time slept was less than specified.

"touch"
    Updates the access and modification times of the specified files. Exits NO RESULT if any file could not be modified for any reason.

"unlink"
    Removes the specified files. Exits NO RESULT if any file could not be removed for any reason.

ENVIRONMENT
The "Test::Cmd::Common" module also uses the "PRESERVE", "PRESERVE_FAIL", "PRESERVE_NO_RESULT", and "PRESERVE_PASS" environment variables from the Test::Cmd module. See the Test::Cmd documentation for details.

SEE ALSO
perl(1), Test::Cmd.

The most involved example of using the "Test::Cmd::Common" module to test a real-world application is the "cons-test" testing suite for the Cons software construction utility. The suite sub-classes "Test::Cmd::Common" to provide common, application-specific infrastructure across a large number of end-to-end application tests. The suite, and other information about Cons, is available at:

        http://www.dsmit.com/cons

AUTHOR
Steven Knight, knight@baldmt.com

ACKNOWLEDGEMENTS
Thanks to Johan Holmberg for asking the question that led to the creation of this package.

The general idea of testing commands in this way, as well as the test reporting of the "pass", "fail" and "no_result" methods, come from the testing framework invented by Peter Miller for his Aegis project change supervisor. Aegis is an excellent bit of work which integrates creation and execution of regression tests into the software development process. Information about Aegis is available at:

        http://www.tip.net.au/~millerp/aegis.html