add test for pipe()

S32-io/pipe.t

@@ -0,0 +1,30 @@
+use v6;
+use Test;
+
+plan 5;
+
+pipes_ok '1',              '',    0, 'Child succeeds but does not print anything';
+pipes_ok 'say 42',         '42',  0, 'Child succeeds and prints something';
+pipes_ok 'exit 1',         '',    1, 'Child fails and prints nothing';
+pipes_ok 'exit 42',        '',   42, 'Child fails and prints nothing';
+pipes_ok 'say 42; exit 7', '42',  7, 'Child fails and prints something';
+
+sub pipes_ok($code, $out, $exit, $desc) {
+    subtest {
+        my $fh = pipe("$*EXECUTABLE -e \"$code\"", :r);
+        ok $fh ~~ IO::Handle, 'pipe() returns an IO::Handle';
+        my $lines = $fh.lines.join('');
+        my $ps = $fh.close;
+        if $exit {
+            nok $ps,            'pipe() returns something falsish on failure';
+            is $ps.exit, $exit, "Proc::Status.exit is $exit";
+            is $lines,   $out,  'got correct output';
+        }
+        else {
+            ok $ps,              'pipe() returns something trueish on success';
+            is $ps.exit,   0,    'Proc::Status.exit is zero for a successful run';
+            is $ps.status, 0,    'Proc::Status.status is zero for a successful run';
+            is $lines,     $out, 'got correct output';
+        }
+    }, $desc
+}