Kevin Reid's blog

While I worked at Google I spent a lot of time doing testing and code review. One of the things I learned from this is:

A test must document what it is testing.

This doesn’t have to be an explicit comment (it might be adequately explained by the name of the test, or the code in it), but either way, it should be obvious to maintainers what the goal of the test is — what property the code under test should have. “This test should continue to pass” is not a sufficient explanation of the goal. Why? Consider these scenarios:

• A test failed. Does that mean…

  • …the test successfully detected the loss of a desired behavior? (This is the ideal case, that we hope to enable by writing and running tests.)

  • …the test incidentally depended on something that is changing but is not significant, such as ordering of something unordered-but-deterministic, or the exact sequence of some method calls? (Ideally, test assertions will be written precisely so that they accept everything that meets requirements, but this is not always feasible or correctly anticipated.)

  • …the test incidentally depended on something that is being intentionally changed, but it wasn’t intending to test that part of the system, which has its own tests?

• A test no longer compiles because you deleted a function (or other declaration/item/symbol) it used. Does that mean…

  • …the test demonstrates a reason why you should not delete that function?

  • …the test needs to be rewritten to test the thing it is about, without incidentally using that function?

  • …the function is necessary to perform this test, so it should continue to exist but be private?

If tests specify the property they are looking for, then maintainers can quickly decide how to respond to a test failure — whether to count it a bug in the code under test, or to change or delete the test.

If they do not, then maintainers will waste time keeping the code conformant to obsolete requirements, or digging through revision history to determine the original intent.

Arrived in California a few days ago; setting up assorted arrangements. I start work in a week.

Anyone (that I know at least somewhat) looking for a Google+ invitation? (I don't know whether they're scarce these days.)

Oh, and I should mention: I have arrived in Mountain View, California and have started my internship at Google with the Caja team.

It’s now confirmed that I'm going to be doing the same thing this summer as last summer: working at Google on Caja.

All comments, congratulations, housing recommendations, and activity suggestions are welcome.

I have finished my internship at Google (which I do want to post about eventually).

I am now about to start classes at Clarkson University. Everything's going smoothly, except the network to my room is broken and I'm connecting over my shiny new phone (hooray for Android 2.2's “Portable Wi-Fi hotspot”) and so I'm temporarily off several of my Internet activities due to bandwidth/latency/intermittency.

(On the upside of technical issues, I managed to get Apple Mail and my phone to talk to Clarkson's Exchange server, so no more having to remember to check my college email more than once a day. What wasn't obvious: When setting up the account in Mail, put the Outlook Web Access server name in both the “Incoming Mail Server” and “Outlook Web Access Server” fields. I haven't figured out how to send mail from their server; perhaps I need to upgrade to Mac OS X 10.6 for that.)

I designed the new logo for Tahoe-LAFS.

I am right this minute packing my luggage and reviewing plans. I will be getting on the train tonight at 8 PM Eastern, and traveling until 9 PM Pacific on Sunday, May 30.

I will probably not have Internet access for most or all of the trip.

One of the things I’ve been procrastinatingah, not had the time to do, being busy with school and other projects, is announcing and working on a job search for this summer. I have posted my resume, but I didn’t even get around to mentioning that. The process really doesn’t excite me that much — it’s essentially research, comparison shopping, which I have never been very fond of.

But, last October, I was contacted out of the blue by a recruiter asking if I was interested in opportunities at — Google. After checking that it wasn’t a spoof I naturally said yes, and after a number of rounds of information exchange and interviews,

This summer, I will be (well, subject to my completing the process of accepting the offer) working as a Software Engineering Intern at Google, with the Caja team, in Mountain View, CA.

So — whoa and yay and other such cheerful words. And thanks to my friends at Google who referred me and nudged the process along.^*

The most uncertain remaining step is finding housing in or near Mountain View (could be as far as San Francisco or San Jose; Google runs a shuttle bus and is convenient to public transportation). Google has provided some general advice-for-interns, but I’d like to hear input from my readers and friends who already live in in the area.

Some parameters:

• I would consider living with other people, but I wouldn’t want to take a chance on a complete unknown. (So if you are someone or know someone with a room...)
• Speaking of taking chances, make the chance of being mugged on the way home in the evening very small, please.
• I am traveling from the east coast, probably by train, so I don’t want to have to transport a lot of stuff, or buy items that I’ll use for only three months — so a furnished space is better.
• I do not own a car, but I know how to drive one.
• I do not own a bicycle, but I used to know how to ride one.
• This will be the first time I have lived outside of my home city for longer than a week’s visit/vacation.

^*Y’know how job search advice is big on saying you should be “networking”? If you’ve thought you’re too much of the non-face-to-face-social non-polite-small-talk would-rather-talk-to-people-through-the-computer sort for that — take me as an example. This opportunity came to me because of other people who knew me entirely through my work on open source projects (E, and thus Caja-CapTP) — I didn’t do anything that I wouldn’t have done for other reasons anyway. I’m not saying you shouldn't do any of the other stuff you might be thinking of — I’m saying this stuff counts.