Learning Testing Heuristics

When I was in junior high school, one of my tasks was to learn metric conversions. My science teacher at the time took this task seriously. To help us remember the kilo, hecto, deca, deci, centi, milli prefixes to meter, liter and gram, he had us memorize a mnemonic. The mnemonic looked like this: KHDMDCM, and there was a sort of song that went through it: “King Henry Danced Merrily…something something something”. Trouble was, I barely had the mnemonic memorized in time for a pop quiz, and I couldn’t remember what each letter stood for. I ended up only being able to write the King Henry song out on my test paper and handing it in. I couldn’t do the required conversions such as decimeters to meters, or kilometers to centimeters. My teacher gave me a cold look when he handed the exams back, and admonished me to start trying. Trouble was, I was trying. I just couldn’t get that stupid mnemonic to make sense in my brain.

At home that night, I sang the King Henry song over and over, repeating what each letter stood for. It was hopeless. I had to constantly look at my cue cards.

My older sister happened along and asked: “What on EARTH are you doing?”

I explained.

“Don’t do it that way,” she said, and quickly sketched out a diagram.

She wrote out all the measurement prefixes from largest to smallest, with “meter, liter, gram” in the center, and drew an arrow going up to the left on one side, and down to the right on the other. I stared at the diagram for a few seconds, and she had me reproduce it cold. Within minutes, I had the image memorized. She then taught me how to use it for conversion. It was a snap. On my metric conversion exam later that week, I ploughed through the questions with ease. “Forget King Henry,” was my thought, “this works way better.” And, forget him I did.

However, over twenty years later, I can still scratch out that conversion diagram and convert deciliters to decaliters, or kilograms to grams on the back of a napkin with relative ease.

“Different people learn differently” my father once told me. His first career was a school teacher, and over twenty five years he taught hundreds of different students. He was surprised by little, and was quite pragmatic. If colors helped you learn and remember, use colors. If mnemonics and little songs worked, try them. If images worked, go with the images. Try to involve most of your senses if you want to remember something, he said. Furthermore, if the system you are trying to use doesn’t work for you, make sure you clearly understand the concept, and then create your own. (These didactic sessions usually came from the depths of a newspaper, my Dad gazing at me through thick rimmed glasses with CBC Radio blasting from a radio in the background.)

When I started working with James Bach, he talked about using mnemonics for testing. I was familiar with, and had used most of his published mnemonics, but I had never memorized them. I used them more for analysis, or once in a while I’d scrawl one out on an index card and try to use it when testing. They seemed much more suited to analysis and planning though, and I was able to use them to generate extremely effective test strategies and plans.

Then one day I saw James at work, testing software. He was thinking out loud, using test heuristics, rattling off testing mnemonics, and simultaneously designing and executing tests under each letter of a mnemonic in real time. He would pause periodically to point out his findings or jot down notes. I’d never seen anything like it, and I knew right then I had to master it. I needed to memorize those mnemonics, so I too could quickly slice through a testing problem (any testing problem) with thorough ease. However, the spectre of King Henry loomed above me, reminding me of my early mnemonic memorization failure.

I had learned other mnemonics that were quite useful and effective, but memorizing mnemonics was a bit of a blind spot for me. Who can forget SOHCAHTOA, an effective way to remember how to calculate the sine, cosine and tangent of an angle? I remembered memorizing that mnemonic and using it to great effect. “Soak-a-toe-ah” I repeated in a unique cadence, and imagined a big toe in a wash basin. The imagery and the rhythmic cadence of “soak-a-toe-ah” helped me remember the mnemonic, and practice helped me remember the application. I could memorize testing mnemonics just as easily, and banish King Henry from my memorization nightmares.

James peered down at me over the rim of his glasses: “You need to memorize testing mnemonics.”

His tone was casual, but firm. To him it was like telling me I needed to learn to cross the street. Obvious. I complained about how I often found it hard to memorize them, and often used other kinds of models.

“That’s because you are memorizing someone else’s. You need to create your own. If they are yours, you’ll remember them.”

I was faithful to that advice, and it has served me well. I’ve added mnemonic memorization and creation to my testing thinking repertoire. I use mnemonics along with diagrams, images, songs, keywords, and guide words. When I teach testing techniques, I find, as my Father did many years ago, that some thinking models appeal to different people in different ways than others. Furthermore, using different thinking models with test heuristics helps me analyze them, enhance them, and learn more about my own work both during analysis and planning, and during execution.

EDIT Update: I SLICED UP FUN is a popular mnemonic I created. I developed it first for myself, then shared with my team, then with everyone else. It has become quite popular on mobile software development projects the world over. Are you curious about mnemonics? If so, imagine me peering over my glasses at you.