Testing Alpha::is_valid_plang()

• new() without 'name' element

        $self = Alpha->new( { string  => 'abcxyz' } ); 
        ok($self, "Alpha->new() returned true value");

• is_valid_plang(): tests for several values of arguments

        $language = 'perl';
        ok($self->is_valid_plang($language), "'$language' is a valid language");

        $language = 'Perl';
        ok($self->is_valid_plang($language), "'$language' is a valid language");

        $language = 'Python';
        ok($self->is_valid_plang($language), "'$language' is a valid language");