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Questions to ask yourself when writing tests

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Re: Questions to ask yourself when writing tests

#11

Post by qaq »

simonhamp wrote: post #6

The most important question to ask when writing tests: Can I do this faster if I don’t write a test? The answer is always no. Even if you are the only person building something, future you will lick your boots clean in gratitude if there are tests. Because even the best developers have to work with their own code sometimes.

I like having tests but I would bet if you audit you production stack it's very likely that a very large portion of it does not really have tests yet is prob most stable part of your stack like Linux kernel etc.

Re: Questions to ask yourself when writing tests

#12

Post by crdoconnor »

simonhamp wrote: post #6

The most important question to ask when writing tests: Can I do this faster if I don’t write a test? The answer is always no. Even if you are the only person building something, future you will lick your boots clean in gratitude if there are tests. Because even the best developers have to work with their own code sometimes.

>Can I do this faster if I don’t write a test? The answer is always no.

I think the answer is mostly no but it's dangerous to think that it's always no.

I've been given many stories in the past for which writing a realistic automated test would have taken days, manual verification took minutes and the code was fairly isolated and did not get changed very frequently.

Writing a test under those circumstances is actually a pretty poor investment.

Re: Questions to ask yourself when writing tests

#13

Post by atticusCr »

The author does not cover any question related to application security. Things like is this parameter/input value properly sanitized, does this piece is/is not vulnerable to injection attacks, does this piece of code performs authentication/authorization checks? Is RBAC properly implemented for this method?

Re: Questions to ask yourself when writing tests

#14

Post by spion »

Here are 3 more questions:

  * Are these tests relying on API that is likely to change?
  * Can I make the API surface area used by all tests even smaller?
  * Can I make a library that wraps the existing API of the unit to 
    get a smaller and/or more stable API for use in the tests only?
These 3 help get tests that withstand refactors.

An example:

An acceptance test for an editing form is relying on the save button having a certain CSS style to find it and click it. This is API that is likely to change. An unrelated change in the looks of a button may break the test.

If we switch to using the text of the button ("Save"), that's better because that is what the user is likely to rely on too when they try to find a sav button. But its still not perfect as the text of the button could change.

The final step is to make a little library function that finds a save button within a certain form. Then we can encode the logic of the test but vary the kinds of text that are considered "save" (or even the method of finding a save button - perhaps a standard CSS class of save buttons in the future!); the test logic itself remains "permanent" since it doesn't rely on any implementation detail anymore.

Re: Questions to ask yourself when writing tests

#16

Post by KirinDave »

simonhamp wrote: post #6

The most important question to ask when writing tests: Can I do this faster if I don’t write a test? The answer is always no. Even if you are the only person building something, future you will lick your boots clean in gratitude if there are tests. Because even the best developers have to work with their own code sometimes.

I wish people would extend this same logic to type systems and formal methods.

Re: Questions to ask yourself when writing tests

#17

Post by KirinDave »

crdoconnor wrote: post #12
simonhamp wrote: post #6

The most important question to ask when writing tests: Can I do this faster if I don’t write a test? The answer is always no. Even if you are the only person building something, future you will lick your boots clean in gratitude if there are tests. Because even the best developers have to work with their own code sometimes.

>Can I do this faster if I don’t write a test? The answer is always no. I think the answer is mostly no but it's dangerous to think that it's always no. I've been given many stories in the past for which writing a realistic automated test would have taken days, manual verification took minutes and the code was fairly isolated and did not get changed very frequently. Writing a test under those circumstances is actuall…

That's a decision you can make, but all you're doing is costing yourself more time later for the benefit of less time now.

Re: Questions to ask yourself when writing tests

#18

Post by atoko »

spion wrote: post #14

Here are 3 more questions: * Are these tests relying on API that is likely to change? * Can I make the API surface area used by all tests even smaller? * Can I make a library that wraps the existing API of the unit to get a smaller and/or more stable API for use in the tests only? These 3 help get tests that withstand refactors. An example: An acceptance test for an editing form is relying on the save button having a…

A small library function like document.getElementById?

Re: Questions to ask yourself when writing tests

#19

Post by simonhamp »

crdoconnor wrote: post #12
simonhamp wrote: post #6

The most important question to ask when writing tests: Can I do this faster if I don’t write a test? The answer is always no. Even if you are the only person building something, future you will lick your boots clean in gratitude if there are tests. Because even the best developers have to work with their own code sometimes.

>Can I do this faster if I don’t write a test? The answer is always no. I think the answer is mostly no but it's dangerous to think that it's always no. I've been given many stories in the past for which writing a realistic automated test would have taken days, manual verification took minutes and the code was fairly isolated and did not get changed very frequently. Writing a test under those circumstances is actuall…

I would be very surprised if an automated test literally took days to write when a manual test is just minutes.

Also the time savings still pay off later, as automated tests usually take seconds to run and there’s no training required - once it’s in the test suite and the test suite runs are automated, it will always run and quickly identify a failure - no “oops, we forgot to show Jim the Intern that he had to test that part manually...”

Setting up your test suite and automation is longer for sure, but not days. Even a complex manual process can be automated relatively quickly... the manual process should be fairly scriptable in any OS nowadays, and most platforms have great test frameworks.

Re: Questions to ask yourself when writing tests

#20

Post by atticusCr »

V2hLe0ThslzRaV2 wrote: post #2

>> "For every part of my code change, if I break the code, will a test fail?" Since "breaking code" is super subjective, and generally speaking, trying to "cover everything" is a recipe for hell. Anyone able to expand on what the author meant by this?

That's actually, IMHO, a good asset that comes out of a good test and code coverage. I would be worried if after adding new piece of code or modifying an existing code if there is not a test that tells me that something is broken due my code.

Here is where testing becomes very helpful.

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