The Zero-One-Infinity rule is a computer science adage from Willem van der Poel meant to compel software designers to avoid arbitrary limits. In thinking about this recently, I’ve come to appreciate zero-one-infinity as a useful heuristic for certain categories of…
Long haul: two years later
When I presented my thoughts on long-haul testing for PNSQC in 2013, I had been steeped in the methodology for probably five years. It’s now two years later; what has changed? One thing I noticed while researching back then which…
A watched app never fails
Watchdogs have been longtime staples of the embedded systems space. But they are also quite useful for distributed services where it is advantageous to attempt automatic recovery from transient errors. When it comes to watchdog implementations, the stakes are understandably…
Destroy all* tests: unit test edition
Sometimes the code we need to write is so simple that we cannot imagine getting it wrong. Going test-first in these cases just seems apt to lead to tedium and tautologies. This could be a fair point if the sole…
Destroy all* tests
Tests have a shelf life. Boris Beizer famously wrote about the pesticide paradox a few decades ago: Yesterday’s elegant, revealing, effective test suite will wear out because programmers and designers, given feedback on their bugs, do modify their programming habits…
One box to rule them all?
If your distributed system supports some form of scale minimization, you may feel a temptation to solve a variety of semi-related problems with the same “one box.” It’s more efficient to reuse code, after all. Unfortunately, it is also easy…
Scale minimization
Long ago, I wrote about high-level testing and alluded to scale minimization as a useful technique in doing so. In this post, I’ll explore this idea a bit more. What is scale minimization? You may have heard it referred to…
Gratuitous complications: unit test fault injection
Sometimes things don’t need to be complicated. I would go so far to say most of the time things don’t need to be complicated. In the words of Uncle Bob Martin, “it is the software engineer’s job to make tough…
Disorderly fault injection
Fault injection is a commonly used testing technique to force the system under test into failure paths, allowing observation and evaluation of the system’s ability to tolerate and recover from errors. There are many fault injection tools available, such as…
If at first you don’t succeed
Retries are a fact of life in testing. That file you are trying to read might be temporarily locked. The network connection could momentarily break. You may need to keep pinging a server for status until it returns the result…