tesh(1) testing shell

SYNOPSIS

tesh [options]... testsuite

DESCRIPTION

Tesh is the testing shell, a specialized shell for running tests. It provides the specified input to the tested commands, and check that they produce the expected output and return the expected value.

OPTIONS

  --cd some/directory : ask tesh to switch the working directory before
                        launching the tests
  --setenv var=value  : set a specific environment variable
  --cfg arg           : add parameter --cfg=arg to each command line
  --log arg           : add parameter --log=arg to each command line
  --enable-coverage   : ignore output lines starting with "profiling:"

TEST SUITE FILE SYTAX

A test suite is composed of one or several command blocks separated by empty lines, each of them being composed of a command to run, its input text and the expected output.

The first char of each line specifies the type of line according to the following list. The second char of each line is ignored.

 `$' command to run in foreground
 `&' command to run in background
 `<' input to pass to the command
 `>' output expected from the command
 `!' metacommand, which can be one of:
     `timeout' <integer>|no
     `expect signal' <signal name>
     `expect return' <integer>
     `output' <ignore|display>
     `setenv <key>=<val>'
 `p' an informative message to print

If the expected output do not match the produced output, or if the command did not end as expected, Tesh provides an error message (see the OUTPUT section below) and stops.

Command blocks examples

In a given command block, you can declare the command, its input and its expected output in the order that you see fit.

    $ cat
    < TOTO
    > TOTO
    > TOTO
    $ cat
    < TOTO
    > TOTO
    < TOTO
    $ cat

You can group several commands together, provided that they don't have any input nor output.

    $ mkdir testdir
    $ cd testdir

Enforcing the command return code

By default, Tesh enforces that the tested command returns 0. If not, it fails with an appropriate message and returns code+40 itself.

You specify that a given command block is expected to return another code as follows:

    # This command MUST return 42
    ! expect return 42
    $ sh -e "exit 42"

The expect return construct applies only to the next command block.

Commands that are expected to raise signals

By default, Tesh detects when the command is killed by a signal (such as SEGV on segfaults). This is usually unexpected and unfortunate. But if not, you can specify that a given command block is expected to fail with a signal as follows:

    # This command MUST raise a segfault
    ! expect signal SIGSEGV
    $ ./some_failing_code

The expect signal construct applies only to the next command block.

Timeouts

By default, no command is allowed to run more than 5 seconds. You can change this value as follows:

    # Allow some more time to the command
    ! timeout 60
    $ ./some_longer_command

You can also disable the timeout completely by passing ``no'' as a value:

    # This command will never timeout
    ! timeout no
    $ ./some_very_long_but_safe_command

Setting environment variables

You can modify the environment of the tested commands as follows:

    ! setenv PATH=/bin
    $ my_command

Not enforcing the expected output

By default, the commands output is matched against the one expected, and an error is raised on discrepancy. Metacommands to change this:
output ignore
The output is completely discarded.
output display
The output is displayed, but no error is issued if it differs from the expected output.
output sort
The output is sorted before comparison (see next section).

Sorting output

If the order of the command output changes between runs, you want to sort it before enforcing that it is exactly what you expect. In SimGrid for example, this happens when parallel execution is activated: User processes are run in parallel at each timestamp, and the output is not reproducible anymore. Until you sort the lines.

You can sort the command output as follows:

    ! output sort
    $ ./some_multithreaded_command

Sorting lines this ways often makes the tesh output very intricate, complicating the error analysis: the process logical order is defeated by the lexicographical sort.

The solution is to prefix each line of your output with temporal information so that lines can be grouped by timestamps. The lexicographical sort then only applies to lines that occured at the same timestamp. Here is a SimGrid example:

    # Sort only lines depending on the first 19 chars
    ! output sort 19
    $ ./some_simgrid_simulator --log=root.fmt:[%10.6r]%e(%i:%[email protected]%h)%e%m%n

This approach may seem surprizing at the first glance but it does its job:

Every timestamps remain separated, as it should;
In each timestamp, the output order of processes become reproducible: that's the lexicographical order of their name;
For each process, the order of its execution is preserved: its messages within a given timestamp are not reordered.

That way, tesh can do its job (no false positive, no false negative) despite the unpredictable order of executions of processes within a timestamp, and reported errors remain easy to analyze (execution of a given process preserved).

This example is very SimGrid oriented, but the feature could even be usable by others, who knows?

BUILTIN COMMANDS

mkfile: creating a file

This command creates a file of the name provided as argument, and adds the content it gets as input.

  $ mkfile myFile
  > some content
  > to the file

It is not possible to use the cat command, as one would expect, because stream redirections are currently not implemented in Tesh.

BUGS, LIMITATIONS AND POSSIBLE IMPROVEMENTS

The main limitation is the lack of stream redirections in the commands (``>'', ``<'' and ``|'' shell constructs and friends). The mkfile builtin command makes this situation bearable.

It would be nice if we could replace the tesh file completely with command line flags when the output is not to be verified.