googletesting: It is not about writing tests, its about writing stories

It is not about writing tests, its about writing stories

Wednesday, September 2, 2009

the transmission should allow the output shaft to be locked, move in same direction (D) as the input shaft, move in opposite (R) or move independently (N)

the transmission should allow the ratio between input and output shaft to be [-1, 0, 1, 2, 3, 4]

the transmission should start in 1st and than switch to higher gear before the engine reaches maximum revolutions.

the transmission should down shift whenever the engine RPM fall bellow 1000 RPMs

the transmission should up-shift whenever the estimated fuel consumption at a higher gear ration is better than the current one.

the transmission should down-shift whenever the gas pedal is depressed more than 50% and the RPM is lower than the engine's peak output RPM.

test to make sure all of the gears work

test to make sure that the engine is not allowed to over-rev

at 3000 RPM input shaft, apply 100% throttle and assert that the transmission goes to 2nd gear.

creating a story which is forcing a particular design decision.

tests are a collection of assumptions which needs to be true at all times.

miss a lot of reasons why things are done in particular way even if we have 100% coverage

test are often brittle because they are tied to particulars of the current implementation

tests are just snapshots and don't tell a story of why the component does something, only that it does.

1 comment :

Bob LauerSeptember 14, 2009 at 8:14 AM
... You could call it "questions" instead of "stories" since (as you have already pointed out) your stories are about the what and not about the how.
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It is not about writing tests, its about writing stories

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