Exactly, but unless those functions are externally callable there is no reason
to test them in isolation.
> On Mar 18, 2020, at 9:04 AM, Ondrej <ondrej.ko...@gmail.com> wrote:
>
>
> That omission is not really relevant. Even if I included an assertion in the
> test, it wouldn't affect the point I am making. I just wanted to have at
> least some source code to reproduce the problem - adding if Calculator(1,2)
> != 3 {t.Error(...)} would make it more of a complete test, but my point is
> entirely different. My point is that top level functions calling further
> functions leads to "inflated" coverage numbers, because I am explicitly not
> testing any of the downstream functionality, just the top level function.
>
> Again, this is not really a technical issue.
>
>> On Wednesday, 18 March 2020 13:29:05 UTC+1, Robert Engels wrote:
>> It’s because you are not writing the top level test correctly - there is no
>> testing at all !
>>
>>>> On Mar 18, 2020, at 7:02 AM, Ondrej <ondre...@gmail.com> wrote:
>>>>
>>>
>>> Hey!
>>>
>>> There's an issue I've been grappling with for ages - say I have a custom
>>> function, Print, that calls six other functions, FormatString, FormatBool,
>>> FormatXYZ, ..., and I have no tests. Once I write some basic tests for
>>> Print, it does call some of the other functions and from looking at my test
>>> coverage, it looks like I have those nested functions covered, but I never
>>> called them explicitly, I never did try all their corner cases, did not
>>> fuzz them or anything.
>>>
>>> It may sound odd or not important, but I have encountered this in almost
>>> every project in Go and other languages - the setup is always the same -
>>> lots of small functions doing their thing and then some orchestrator that
>>> integrates everything (could be a cli, could be an endpoint etc.) and once
>>> I set that up, coverage spikes up.
>>>
>>> Here's a simple example:
>>>
>>> // calculator.go
>>> package calculator
>>>
>>> func Add(a, b int) int {
>>> return a+b
>>> }
>>>
>>> func Calculator(a, b int) int {
>>> return Add(a, b)
>>> }
>>>
>>> // calculator_test.go
>>> package calculator
>>>
>>> import "testing"
>>>
>>> func TestCalculator(t *testing.T) {
>>> s := Calculator(1, 2)
>>> _ = s
>>> }
>>>
>>> In this case, Calculator is covered, and so is Add, but I never tested how
>>> Add behaves for values close to the int maximum and with other potentially
>>> dangerous edge cases.
>>>
>>> I've though about this over the years a tiny bit and never really found a
>>> great solution, because it's not really a technical thing, it's more about
>>> the workflow and attitude to testing.
>>>
>>> I prototyped a simple tool that looks up all the exported functions and
>>> methods in a package and then checks if they are *explicitly* called in our
>>> tests. This does not guarantee anything, but at least we know they were
>>> explicitly used, not indirectly called within a different function. The
>>> prototype does not quite work for methods, because I got kind of lost in
>>> the go/{parser,ast} indirections. Also reassigning functions as first class
>>> values and then calling them from a different variable will probably also
>>> break it.
>>>
>>> So it does give a lot of false positives for methods, but should be mostly
>>> fine for functions.
>>>
>>> While it probably does not solve any problems for any people apart from me,
>>> I'll try and fix the method issues, because I do really need it for my own
>>> test writing.
>>>
>>> Do let me know if there's a better solution to this or if you've
>>> encountered this and have some thoughts on the topic.
>>>
>>> Thanks!
>>>
>>> Ondrej
>>> --
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>>> <main.go>
>
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