Find an existing test under t/ that is written use the perl test modules.

parrot tests tend to have a single perl test that generates multiple lines of output; Each of these multiple lines of output needs to be a single test in the parrot model.

For example, here's on old style single test with two outputs.

pir_output_is( <<'CODE', <<'OUT', 'string isa and pmc isa have same result' );
.sub main
     .local pmc class, obj
     class = new 'Class'
     obj = class.'new'()
     $I0 = isa obj, 'Object'
     print $I0
     print "\n"
     .local pmc cl
     cl = new 'String'
     cl = 'Object'
     $I1 = isa obj, cl
     print $I1
     print "\n"
.end
CODE
1
1
OUT

To convert this to pir tests, you simply strip off the surrounding perl wrapper and leave the heredoc; give the sub a unique name, for example, based on your test description.

.sub string_isa_and_pmc_isa_have_same_result
     .local pmc class, obj
     class = new 'Class'
     obj = class.'new'()
     $I0 = isa obj, 'Object'
     print $I0
     print "\n"
     .local pmc cl
     cl = new 'String'
     cl = 'Object'
     $I1 = isa obj, cl
     print $I1
     print "\n"
.end

Next, we need to convert the output to use PIR's test more subs...

.sub string_isa_and_pmc_isa_have_same_result
    .local pmc class, obj
    class = new 'Class'
    obj = class.'new'()
    $I0 = isa obj, 'Object'
    ok ($I0, 'isa Class instance an Object')

    .local pmc cl
    cl = new 'String'
    cl = 'Object'
    $I1 = isa obj, cl
    ok ($I1, 'isa String instance an Object')
.end

Finally, we need a harness to run this sub with the two tests:

.sub main :main
    .include 'include/test_more.pir'

    plan(2)

    string_isa_and_pmc_isa_have_same_result()
.end

Finally, be sure to update the coda to be a PIR coda rather than the perl one.

Here is a brief list of some potential stumbling blocks and ways around them:

* There are a number of tests which confirm proper error reporting. This can be done in PIR in two ways. The simplest method is to create an exception handler and check the exception message.

pasm_error_output_like( <<'CODE', <<'OUTPUT', "Malformed string: real part" );
    new P0, 'Complex'
    set P0, "q + 3i"
    end
CODE
/Complex: malformed string/
OUTPUT

becomes...

.sub exception_malformed_string__imaginary_part
    new P0, 'Complex'
    push_eh handler
        set P0, "q + 3i"
    pop_eh
handler:
    .local pmc exception
    .local string message
    .get_results (exception)

    message = exception['message']
    is( message, 'Complex: malformed string', 'Complex: malformed string' )
.end

Alternatively, you can create a EventHandler PMC and check for the appropriate error type. See t/pmc/ro.t for an example. This method may be preferable

* Some tests create new classes and add methods to those namespaces. In a consolidated file you will need to make sure the new class names don't collide (you'll probably find a number of Foo and Bar classes), and you will need to make sure you return to the root namespace after the test completes.

.namespace [] # Return to the root namespace

* Many tests are skipped based on the operating system. You can test for this in PIR with the following:

    .include "iglobals.pasm" 
    .local pmc config_hash, interp 
    interp = getinterp 
    config_hash = interp[.IGLOBALS_CONFIG_HASH] 
    $S0 = config_hash["os_name"] 
    eq $S0, "MSWin32", win32fail
    ...
    .return()
win32fail:
    skip( 10, 'skipping ___ tests under MSWin' )