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```{index} single: TAP::Harness::Env
```

# TAP::Harness::Env

Parsing harness related environmental variables where appropriate

## VERSION

Version 3.52

## SYNOPSIS

```perl
my $harness = TAP::Harness::Env->create(\%extra_args)
```

## DESCRIPTION

This module implements the environmental variables that [Test::Harness](../../Test/Harness.md) uses with TAP::Harness, and instantiates the appropriate class with the appropriate arguments.

## METHODS

- create( \\%args )

    This function reads the environment and generates an appropriate argument hash from it. If given any arguments in `%extra_args`, these will override the environmental defaults. In accepts `harness_class` (which defaults to `TAP::Harness`), and any argument the harness class accepts.

## ENVIRONMENTAL VARIABLES

- `HARNESS_PERL_SWITCHES`

    Setting this adds perl command line switches to each test file run.

    For example, `HARNESS_PERL_SWITCHES=-T` will turn on taint mode.
    `HARNESS_PERL_SWITCHES=-MDevel::Cover` will run `Devel::Cover` for
    each test.

- `HARNESS_VERBOSE`

    If true, `TAP::Harness` will output the verbose results of running
    its tests.

- `HARNESS_SUBCLASS`

    Specifies a TAP::Harness subclass to be used in place of TAP::Harness.

- `HARNESS_OPTIONS`

    Provide additional options to the harness. Currently supported options are:

    - `j<n>`

        Run &lt;n> (default 9) parallel jobs.

    - `c`

        Try to color output. See ["new" in TAP::Formatter::Base](../Formatter/Base.md).

    - `a<file.tgz>`

        Will use [TAP::Harness::Archive](https://metacpan.org/pod/TAP::Harness::Archive) as the harness class, and save the TAP to
        `file.tgz`

    - `fPackage-With-Dashes`

        Set the formatter\_class of the harness being run. Since the `HARNESS_OPTIONS`
        is separated by `:`, we use `-` instead.

    Multiple options may be separated by colons:

    ```text
    HARNESS_OPTIONS=j9:c make test
    ```

- `HARNESS_TIMER`

    Setting this to true will make the harness display the number of
    milliseconds each test took.  You can also use `prove`'s `--timer`
    switch.

- `HARNESS_COLOR`

    Attempt to produce color output.

- `HARNESS_IGNORE_EXIT`

    If set to a true value instruct `TAP::Parser` to ignore exit and wait
    status from test scripts.