[RESOLVED] intercepting mail() for unit testing

evan_k

I'm writing a unit testing suite (using PHPUnit) for some code that has extensive mail-related capabilities, and I'd like to write specific unit tests for the mail sending features. my issue, however, is how to get these mail messages into the test suite and dissect them in the test cases.

My first thought was to override the ini setting for sendmail_path, and pipe them into a separate script or file. but that can only be done from the php.ini or the httpd.conf, and I don't want to f*** up everything else on the same webserver while i'm doing my testing.

My second thought was to override the mail() builtin and replace it with a custom function, but it seems the only way to rename/remove functions is with the APD or runkit. This requires one of two dangerous and/or unstable compiled extensions. Extensions that, notably, are difficult to compile on some operating systems without going through dependency hell (ie: OS X).

So my question is this...How can I test mail functionality in a reasonable manner, without requiring dangerous extensions or drastic global configuration changes? Or can I at all?

Shrike

It's a little surprising that you are at the point of using unit testing and yet still using mail() directly. Is it a possibility to use a library to send emails? That way you can easily add a mock object or stub to do the tests.

Another option might be to subclass the class your trying to test, and override the relevant methods in a way that is testable?

evan_k

why is that surprising? i've been building and refining unit tests since the project was started, something that I've always regarded as good practice? and what's wrong with using [FONT="Courier New"]mail()[/FONT] directly (or in my case, [FONT="Courier New"]error_log()[/FONT] which uses [FONT="Courier New"]mail()[/FONT] internally)? i'm not trying to be confrontational or anything, i'm asking seriously.

differing methodologies aside, the idea of subclassing sounds feasible and rather clean. I was flirting with a hackish process of mailing localhost, and then reading directly from the local mbox file. so, compared to that, the subclassing idea is a godsend 🙂

jazz_snob

Ideally when you talk to a service layer, like something that sends emails, it would be nice to encapsulate that in something that is easily testible. I've not done that yet, but thats the idea.

Even if you did that at some point you'd have to verify that it actually does what its supposed to: set headers, boundry markers, email body, etc correctly. Now, if the emails are being sent OK you can simply look at the raw message to verify all these things...which would be difficult to automate.

Your idea of looking in mbox is actually pretty decent. If you had your own linux development box you could install nullmailer....then after your mail is "sent" you can look in the queue, find the message, and check it. Again, difficult to automate. If somehow you made sure the only message in the queue (or mbox if you go that route) was going to be the message you sent, that would make automation a little easier.

Testing mail is even worse than testing database layer. Its even worse in production environments where sys. engineers might be messing w/ filters that cause perfectly good code to stop working. I won't mention any names here 🙂

Shrike

evan_k wrote:
why is that surprising? i've been building and refining unit tests since the project was started, something that I've always regarded as good practice? and what's wrong with using [FONT="Courier New"]mail()[/FONT] directly (or in my case, [FONT="Courier New"]error_log()[/FONT] which uses [FONT="Courier New"]mail()[/FONT] internally)? i'm not trying to be confrontational or anything, i'm asking seriously.

differing methodologies aside, the idea of subclassing sounds feasible and rather clean. I was flirting with a hackish process of mailing localhost, and then reading directly from the local mbox file. so, compared to that, the subclassing idea is a godsend 🙂

I'm not discounting unit tests, they are absolutely a good practice. However PHP's mail function is rather basic and there are lots of good libraries out there which simplify the intricacies. If you start of using one (assuming its object oriented) you can easily mock it in your tests.