YAPC::NA 2016, ‎Unit tests automation for legacy code‎ talk by Denis Shirokov

1. Unit tests automation for legacy code
Denis Shirokov
Rexuni.com
YAPC::NA 2016

2. Simple situation
package Users;
use strict;
use warnings;
use DB;
sub get {
my ($user_id) = @_;
my $user = DB::fetch_query( "SELECT * FROM users WHERE id = ?", $user_id );
if ($user) {
return $user;
} else {
die('no user found');
}
}
1;

3. Subroutine execution
use Users;
use Data::Dumper;
print Dumper Users::get(1);

4. Test for simple situation
sub fetch_exists : Auto {
my ($self) = @_;
$self->addStub('DB::fetch_query');
my $result = Users::get(1);
$self->setResult($result);
}

5. Record/Play mode
sub get {
my ($user_id) = @_;
my $user = DB::fetch_query( "SELECT * FROM users WHERE id = ?", $user_id );
if ($user) {
return $user;
} else {
die('no user found');
}
}

6. Database change
package Users;
use strict;
use warnings;
use DB;
sub get {
my ($user_id) = @_;
my $user = DB::fetch_query( "SELECT * FROM users WHERE id = ?", $user_id );
if ($user) {
return $user;
} else {
die('no user found');
}
}
1;

7. Update mode

9. Exception example
sub fetch_not_exists : Auto {
my ($self) = @_;
$self->addStub('DB::fetch_query');
my $result = Users::get(-42);
return $self->setResult($result);
}

11. Ensure function call
package Users;
...
sub delete {
my ($user_id) = @_;
DB::query( "DELETE FROM users WHERE id = ?", $user_id );
return 1;
}

12. Test for user deletion
sub delete_user : Auto {
my ($self) = @_;
$self->addMock('DB::query');
my $result = Users::delete(1);
$self->setResult($result);
}

13. Questions?

14. Thank you
Denis
ShirokovRexuni.com