Re: [racket-users] Testing & global variables
> On Aug 7, 2018, at 10:56 AM, Alexis King wrote: > > I guess I’ll take the bait and give the obvious-but-unhelpful answer, > “Don’t use global variables.” :) > > I’m joking, but only just barely. It seems difficult to give concrete > advice without knowing more details about your program and why you felt > it was necessary to use global mutable state in the first place, so > absent some reason why you need them, I have to recommend you just > refactor your code to eliminate the globals. The standard techniques for > writing testable code in other languages still apply in Racket, most > notably dependency injection (aka “passing arguments to functions”). > Racket also provides a few tools of its own for managing that kind of > dynamic parameterization, such as parameters and units. > > Theoretically, an alternative solution would be to create a separate > namespace (via racket/sandbox or otherwise) for each test file, allowing > each test to use its own instantiation of the library. This almost > certainly isn’t what you actually want, though, since real (non-test) > clients of your library will bump into the same problem, and expecting > them to do the same workaround is unreasonable. Indeed, I think the > difficulty of testing an API like this means the the test suite is doing > what it probably should: hinting that your API is hard to work with and > needs to be changed. > > Alexis After some preliminary testing it looks like Racket’s parameter is exactly what I need! Thanks! Kevin -- You received this message because you are subscribed to the Google Groups "Racket Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: [racket-users] Testing & global variables
If this is a problem only in your test code, you could write a function to reset/re-initialize the global state, and call that function at the beginning of each test. If you want to have a "global state" for each of the file that requires your module, global variables might not be the right approach... Alex. On Wednesday, August 8, 2018 at 1:29:38 AM UTC+8, lysseus wrote: > > I’ve got a library that takes maintains global variables. I’d like to be > able to test different test files that require this library, but of course > if I require those files into a single test file for testing various > combinations of data it corrupts the global variables, which are only valid > for a single instance of test file. > > Conceptually it looks like: > > Library-File > global a > library-functions > Test-file-1 > require Library-file > test-data-file-1 > Test-file-2 > require Library-file > test-data-file-2 > Master-test-file > require Test-file-1 Test-file-2 ;; doesn’t work of course…. > > Any suggestions are appreciated. > > Kevin > > > -- You received this message because you are subscribed to the Google Groups "Racket Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: [racket-users] Testing & global variables
> On Aug 7, 2018, at 10:56 AM, Alexis King wrote: > > I guess I’ll take the bait and give the obvious-but-unhelpful answer, > “Don’t use global variables.” :) > > I’m joking, but only just barely. It seems difficult to give concrete > advice without knowing more details about your program and why you felt > it was necessary to use global mutable state in the first place, so > absent some reason why you need them, I have to recommend you just > refactor your code to eliminate the globals. The standard techniques for > writing testable code in other languages still apply in Racket, most > notably dependency injection (aka “passing arguments to functions”). > Racket also provides a few tools of its own for managing that kind of > dynamic parameterization, such as parameters and units. > > Theoretically, an alternative solution would be to create a separate > namespace (via racket/sandbox or otherwise) for each test file, allowing > each test to use its own instantiation of the library. This almost > certainly isn’t what you actually want, though, since real (non-test) > clients of your library will bump into the same problem, and expecting > them to do the same workaround is unreasonable. Indeed, I think the > difficulty of testing an API like this means the the test suite is doing > what it probably should: hinting that your API is hard to work with and > needs to be changed. > > Alexis Here’s a more concrete example: Test-file-1 (require library) (fact foo 10) (fact bar 30) (ans (? 30)) So the program collects facts and other prolog-like statement into the global, then allows that data to be queried (similar to datalog, although I’m not sure of datalog’s internals only its syntax and what it does). I suppose what would be interesting would be some way of having the library understand what module it is a part of and keep track of its data individually. I could probably do that by replacing the globals with a hash table and since fact, and, etc are macros I could grab the path /filename from the environment and pass that on to the library…. parameters are something I’ve not played around with much, but that’s something I’ll look into. Kevin -- You received this message because you are subscribed to the Google Groups "Racket Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: [racket-users] Testing & global variables
I guess I’ll take the bait and give the obvious-but-unhelpful answer, “Don’t use global variables.” :) I’m joking, but only just barely. It seems difficult to give concrete advice without knowing more details about your program and why you felt it was necessary to use global mutable state in the first place, so absent some reason why you need them, I have to recommend you just refactor your code to eliminate the globals. The standard techniques for writing testable code in other languages still apply in Racket, most notably dependency injection (aka “passing arguments to functions”). Racket also provides a few tools of its own for managing that kind of dynamic parameterization, such as parameters and units. Theoretically, an alternative solution would be to create a separate namespace (via racket/sandbox or otherwise) for each test file, allowing each test to use its own instantiation of the library. This almost certainly isn’t what you actually want, though, since real (non-test) clients of your library will bump into the same problem, and expecting them to do the same workaround is unreasonable. Indeed, I think the difficulty of testing an API like this means the the test suite is doing what it probably should: hinting that your API is hard to work with and needs to be changed. Alexis > On Aug 7, 2018, at 12:29, Kevin Forchione wrote: > > I’ve got a library that takes maintains global variables. I’d like > to be able to test different test files that require this library, but > of course if I require those files into a single test file for testing > various combinations of data it corrupts the global variables, which > are only valid for a single instance of test file. > > Conceptually it looks like: > > Library-File > global a > library-functions > Test-file-1 > require Library-file > test-data-file-1 > Test-file-2 > require Library-file > test-data-file-2 > Master-test-file > require Test-file-1 Test-file-2 ;; doesn’t work of course…. > > Any suggestions are appreciated. > > Kevin -- You received this message because you are subscribed to the Google Groups "Racket Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: [racket-users] Testing & global variables
I’ve got a library that takes maintains global variables. I’d like to be able to test different test files that require this library, but of course if I require those files into a single test file for testing various combinations of data it corrupts the global variables, which are only valid for a single instance of test file. Conceptually it looks like: Library-File global a library-functions Test-file-1 require Library-file test-data-file-1 Test-file-2 require Library-file test-data-file-2 Master-test-file require Test-file-1 Test-file-2 ;; doesn’t work of course…. Any suggestions are appreciated. Kevin -- You received this message because you are subscribed to the Google Groups "Racket Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
