$ cat subst-mutate-numeric.t
use v6;
use Test;

plan 10;

my $foo = 70;
my $match = $foo.subst-mutate(7, 2);
is $foo, 20, 'can use subst-mutate with variable of type Int';
is $match.Str, 7, 'matched text is correct';
isa_ok $foo, Str, 'type changed to Str after applying method subst-mutate';

$foo = 2/5;
$match = $foo.subst-mutate(2, 3);
is $foo, 0.4, 'can use subst-mutate with variable of type Rat';
isa_ok $match, Any, 'no match returned';
isa_ok $foo, Str, 'type changed to Str after applying method subst-mutate';

$foo = 2/5;
$match = $foo.subst-mutate(4, 6);
is $foo, 0.6, 'substition happens after stringification (1)';
is $match.Str, 4, 'matched text is correct';

$foo = pi;
$match = $foo.subst-mutate(3, 4, :g);
is $foo, 4.14159265458979, 'substition happens after stringification (2)';
is $match.Str, '3 3', 'matched text is correct';

done;