NAME Test::Cmd - Perl module for portable testing of commands and scripts SYNOPSIS use Test::Cmd; $test = Test::Cmd->new(prog => 'program_or_script_to_test', interpreter => 'script_interpreter', string => 'identifier_string', workdir => '', subdir => 'dir', verbose => 1); $test->verbose(1); $test->prog('program_or_script_to_test'); $test->basename(@suffixlist); $test->interpreter('script_interpreter'); $test->string('identifier string'); $test->workdir('prefix'); $test->workpath('subdir', 'file'); $test->subdir('subdir', ...); $test->subdir(['sub', 'dir'], ...); $test->write('file', <<'EOF'); contents of file EOF $test->write(['subdir', 'file'], <<'EOF'); contents of file EOF $test->read(\$contents, 'file'); $test->read(\$contents, ['subdir', 'file']); $test->read(\@lines, 'file'); $test->read(\@lines, ['subdir', 'file']); $test->writable('dir', rwflag); $test->preserve(condition, ...); $test->cleanup(condition); $test->run(chdir => 'dir', args => 'arguments'); $test->pass(condition); $test->pass(condition, funcref); $test->fail(condition); $test->fail(condition, funcref); $test->fail(condition, funcref, caller); $test->no_result(condition); $test->no_result(condition, funcref); $test->no_result(condition, funcref, caller); $test->stdout(); $test->stderr(); $test->diff(); $test->here(); DESCRIPTION The `Test::Cmd' module provides a framework for portable automated testing of executable commands and scripts, especially commands and scripts that require file system interaction. This module is not restricted to testing Perl scripts; the command or script to be tested may be any executable or a script in any language, provided a means exists to execute the script on the local system. In addition to running tests and evaluating conditions, the `Test::Cmd' module manages and cleans up one or more temporary workspace directories, and provides methods for creating files and directories in those workspace directories from in-line data (that is, here documents). This allows tests to be completely self-contained. The `Test::Cmd' module manipulates filenames and pathnames using the `File::Spec' module to support writing tests portably across a variety of operating and file systems. The `Test::Cmd' class is in fact a subclass of the `File::Spec' class, and `File::Spec' methods (`catfile', `file_name_is_absolute', etc.) are available through the `Test::Cmd' class and its instances. Consequently, tests written using `Test::Cmd' need not separately import the `File::Spec' module. A `Test::Cmd' environment object is created via the usual invocation: $test = Test::Cmd->new(); Arguments to the `Test::Cmd::new' method are keyword-value pairs that may be used to initialize the object, typically by invoking the same-named method as the keyword. The `Test::Cmd' module may be used in conjunction with the `Test' module to report test results in a format suitable for the `Test::Harness' module. A typical use would be to call the `Test::Cmd' methods to prepare and execute the test, and call the `ok' method exported by the `Test' module to test the conditions: use Test; use Test::Cmd; BEGIN { $| = 1; plan => 2 } $test = Test::Cmd->new(prog => 'test_program', workdir => ''); ok($test); $wrote_file = $test->write('input_file', <<'EOF'); This is input to test_program, which we expect to process this and exit successfully (status 0). EOF ok($wrote_file); $test->run(args => 'input_file'); ok($? == 0); Alternatively, the `Test::Cmd' module provides `pass', `fail', and `no_result' methods that report test results differently. These methods terminate the test immediately, reporting PASSED, FAILED, or NO RESULT respectively, and exiting with status 0 (success), 1 or 2 respectively. This allows for a distinction between an actual failed test and a test that could not be properly evaluated because of an external condition (such as a full file system or incorrect permissions): use Test::Cmd; $test = Test::Cmd->new(prog => 'test_program', workdir => ''); Test::Cmd->no_result(! $test); $wrote_file = $test->write('input_file', <<'EOF'); This is input to test_program, which we expect to process this and exit successfully (status 0). EOF $test->no_result(! $wrote_file); $test->run(args => 'input_file'); $test->fail($? != 0); $test->pass; It is not a good idea to intermix the two reporting models. If you use the `Test' module and its `ok' method, do not use the `Test::Cmd' `pass', `fail' or `no_result' methods, and vice versa. METHODS Methods supported by the `Test::Cmd' module include: `new' Create a new `Test::Cmd' environment. Arguments with which to initialize the environment are passed in as keyword-value pairs. `verbose' Sets the verbose level for the environment object to the specified value. `prog' Specifies the executable program or script to be tested. Returns the absolute path name of the current program or script. `basename' Returns the basename of the current program or script. Any specified arguments are a list of file suffixes that may be stripped from the basename. `interpreter' Specifies the program to be used to interpret `prog' as a script. Returns the current value of `interpreter'. `string' Specifies an identifier string for the functionality being tested to be printed on failure or no result. `workdir' When an argument is specified, creates a temporary working directory with the specified name. If the argument is a NULL string (''), the directory is named `testcmd' by default, followed by the unique ID of the executing process. Returns the pathname to the temporary working directory. `workpath' Returns the absolute path name to a subdirectory or file under the current temporary working directory by concatenating the temporary working directory name with the specified arguments. `subdir' Creates new subdirectories under the temporary working dir, one for each argument. An argument may be an array reference, in which case the array elements are concatenated together using the `File::Spec-&'catfile> method. Subdirectories multiple levels deep must be created via a separate argument for each level: $test->subdir('sub', ['sub', 'dir'], [qw(sub dir ectory)]); Returns the number of subdirectories actually created. `write' Writes the specified text (second argument) to the specified file name (first argument). The file name may be an array reference, in which case all the array elements except the last are subdirectory names to be concatenated together. The file is created under the temporary working directory. Any subdirectories in the path must already exist. `read' Reads the contents of the specified file name (second argument) into the scalar or array referred to by the first argument. The file name may be an array reference, in which case all the array elements except the last are subdirectory names to be concatenated together. The file is assumed to be under the temporary working directory unless it is an absolute path name. Returns TRUE on successfully opening and reading the file, FALSE otherwise. `writable' Makes the specified directory tree writable (`rwflag' == TRUE) or not writable (`rwflag' == FALSE). `preserve' Arranges for the temporary working directories for the specified `Test::Cmd' environment to be preserved for one or more conditions. If no conditions are specified, arranges for the temporary working directories to be preserved for all conditions. `cleanup' Removes any temporary working directories for the specified `Test::Cmd' environment. If the environment variable `PRESERVE' was set when the `Test::Cmd' module was loaded, temporary working directories are not removed. If any of the environment variables `PRESERVE_PASS', `PRESERVE_FAIL', or `PRESERVE_NO_RESULT' were set when the `Test::Cmd' module was loaded, then temporary working directories are not removed if the test passed, failed, or had no result, respectively. Temporary working directories are also preserved for conditions specified via the `preserve' method. Typically, this method is not called directly, but is used when the script exits to clean up temporary working directories as appropriate for the exit status. `run' Runs a test of the program or script for the test environment. Standard output and error output are saved for future retrieval via the `stdout' and `stderr' methods. Arguments are supplied as keyword-value pairs: `args' Specifies the command-line arguments to be supplied to the program or script under test for this run: $test->run(args => 'arg1 arg2'); `chdir' Changes directory to the path specified as the value argument: $test->run(chdir => 'xyzzy'); If the specified path is not an absolute path name (begins with '/' on Unix systems), then the subdirectory is relative to the temporary working directory for the environment (`$test-&'workdir>). Note that, by default, the `Test::Cmd' module does NOT chdir to the temporary working directory, so to execute the test under the temporary working directory, you must specify an explicit `chdir' to the current directory: $test->run(chdir => '.'); # Unix-specific $test->run(chdir => $test->curdir); # portable Returns the return value from the system() call used to invoke the program or script. `pass' Exits the test successfully. Reports "PASSED" on the error output and exits with a status of 0. If a condition is supplied, only exits the test if the condition evaluates TRUE. If a function reference is supplied, executes the function before reporting and exiting. `fail' Exits the test unsuccessfully. Reports "FAILED test of {string} at line {line} of {file}." on the error output and exits with a status of 1. If a condition is supplied, only exits the test if the condition evaluates TRUE. If a function reference is supplied, executes the function before reporting and exiting. If a caller level is supplied, prints a simple calling trace N levels deep as part of reporting the failure. `no_result' Exits the test with an indeterminate result (the test could not be performed due to external conditions such as, for example, a full file system). Reports "NO RESULT for test of {string} at line {line} of {file}." on the error output and exits with a status of 2. If a condition is supplied, only exits the test if the condition evaluates TRUE. If a function reference is supplied, executes the function before reporting and exiting. If a caller level is supplied, prints a simple calling trace N levels deep as part of reporting the failure. `stdout' Returns the standard output from the specified run number. If there is no specified run number, then returns the standard output of the last run. Returns the standard output as either a scalar or an array of output lines, as appropriate for the calling context. Returns `undef' if there has been no test run. `stderr' Returns the error output from the specified run number. If there is no specified run number, then returns the error output of the last run. Returns the error output as either a scalar or an array of output lines, as apporpriate for the calling context. Returns `undef' if there has been no test run. `diff' To Be Written. `here' Returns the absolute path name of the current working directory. (This is essentially the same as the `Cwd::cwd' method, except that the `Test::Cmd::here' method preserves the directory separators exactly as returned by the underlying operating-system-dependent method. The `Cwd::cwd' method canonicalizes all directory separators to '/', which makes for consistent path name representations within Perl, but may mess up another program or script to which you try to pass the path name.) ENVIRONMENT Several environment variables affect the default values in a newly created `Test::Cmd' environment object. These environment variables must be set when the module is loaded, not when the object is created. `PRESERVE' If set to a true value, all temporary working directories will be preserved on exit, regardless of success or failure of the test. The full path names of all temporary working directories will be reported on error output. `PRESERVE_FAIL' If set to a true value, all temporary working directories will be preserved on exit from a failed test. The full path names of all temporary working directories will be reported on error output. `PRESERVE_NO_RESULT' If set to a true value, all temporary working directories will be preserved on exit from a test for which there is no result. The full path names of all temporary working directories will be reported on error output. `PRESERVE_PASS' If set to a true value, all temporary working directories will be preserved on exit from a successful test. The full path names of all temporary working directories will be reported on error output. `VERBOSE' When set to a true value, enables verbose reporting of various internal things (path names, exact command line being executed, etc.). PORTABLE TESTS Although the `Test::Cmd' module is intended to make it easier to write portable tests for portable utilities that interact with file systems, it is still very easy to write non-portable tests if you're not careful. The best and most comprehensive set of portability guidelines is the standard "Writing portable Perl" document at: http://www.perl.com/pub/doc/manual/html/pod/perlport.html To reiterate one important point from the "WpP" document: Not all Perl programs have to be portable. If the program or script you're testing is UNIX-specific, you can (and should) use the `Test::Cmd' module to write UNIX-specific tests. That having been said, here are some hints that may help keep your tests portable, if that's a requirement. Use the `Test::Cmd-&'here> method for current directory path. The normal Perl way to fetch the current working directory is to use the `Cwd::cwd' method. Unfortunately, the `Cwd::cwd' method canonicalizes the path name it returns, changing the native directory separators into the forward slashes favored by Perl and UNIX. For most Perl scripts, this makes a great deal of sense and keeps code uncluttered. Passing in a file name that has had its directory separators altered, however, may confuse the command or script under test, or make it difficult to compare output from the command or script with an expected result. The `Test::Cmd::here' method returns the absolute path name of the current working directory, like `Cwd::cwd', but does not manipulate the returned path in any way. Use `File::Spec' methods for manipulating path names. The `File::Spec' module provides a system-independent interface for manipulating path names. Because the `Test::Cmd' class is a sub-class of the `File::Spec' class, you can use these methods directly as follows: if (! Test::Cmd->file_name_is_absolute($prog)) { my $prog = Test::Cmd->catfile(Test::Cmd->here, $prog); } For details about the available methods and their use, see the documentation for the `File::Spec' module and its sub- modules, especially the `File::Spec::Unix' modules. Use `Config' for file-name suffixes, where possible. The standard `Config' module provides values that reflect the file-name suffixes on the system for which the Perl executable was built. This provides convenient portability for situations where a file name may have different extensions on different systems: $foo_exe = "foo$Config{_exe}"; ok(-f $foo_exe); (Unfortunately, there is no existing `$Config' value that specifies the suffix for a directly-executable Perl script.) Avoid generating executable programs or scripts. How to make a file or script executable varies widely from system to system, some systems using file name extensions to indicate executability, others using a file permission bit. The differences are complicated to accomodate in a portable test script. The easiest way to deal with this complexity is to avoid it if you can. If your test somehow requires executing a script that you generate from the test itself, the best way is to generate the script in Perl and then explicitly feed it to the Perl executable on the local system. To be maximally portable, use the `$^X' variable instead of hard-coding "perl" into the string you execute: $line = "This is output from the generated perl script."; $test->write('script', <write('script', <workdir); chmod(0755, 'script'); # POSIX-SPECIFIC $output = `script`; ok($output eq "$line\n"); Addtional hints on writing portable tests are welcome. SEE ALSO perl(1), File::Find(3), File::Spec(3), Test(3), Test::Harness(3). A rudimentary page for the Test::Cmd module is available at: http://www.baldmt.com/Test-Cmd/ AUTHORS Steven Knight, knight@baldmt.com ACKNOWLEDGEMENTS Thanks to Greg Spencer for the inspiration to create this package and the initial draft of its implementation as a specific testing package for the Cons software construction utility. Information about Cons is available at: http://www.dsmit.com/cons/ The general idea of managing temporary working directories 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