D4no0
I seem to be getting some strange undefined behavior when defining multiple separated mocks for the same module in the same test:
HttpClientMock
|> expect(:request, fn request -> build_response() end)
|> allow(self(), fn -> Process.whereis(MyProcess) end)
# Later in that same test
HttpClientMock
|> expect(:request, fn request -> build_another_response() end)
|> allow(self(), fn -> Process.whereis(MyNewProcess) end)
Is this a limitation that Mox has? I’ve read already the documentation a few times and I couldn’t find any things specified about this, it is completely unclear what happens under the hood as it seems these definitions are doing only side-effects.
Where Next?
Trending in Questions
Other Trending Topics
Latest on Elixir Forum
Sponsor Spotlight
Producing high quality Elixir screencasts since 2017.
Categories:
Sub Categories:
Forums
Popular Tags
- #ecto
- #liveview
- #troubleshooting
- #learning-elixir
- #library
- #deployment
- #erlang
- #testing
- #genserver
- #mix
- #absinthe
- #remote-other
- #otp
- #plug
- #how-to-question
- #macros
- #postgres
- #elixirconf
- #channels
- #exunit
- #discussion
- #code-sync
- #podcasts
- #javascript
- #onsite
- #dialyzer
- #docker
- #authentication
- #umbrella
- #full-time-contract
- #podcasts-by-brainlid
- #ecto-query
- #elixirconf-us
- #ai
- #blog-post
- #elixir-ls
- #phoenix_html
- #iex
- #graphql
- #genstage
- #websockets
- #supervisor
- #advent-of-code
- #distillery
- #processes
- #api
- #forms
- #elixirconf-eu
- #metaprogramming
- #hex
Our Sponsors
Build Elixir applications with speed and confidence.
Supporting innovation across the BEAM ecosystem.
Catch errors, track performance, monitor hosts and more.
Error tracking, logs, uptime, and Just Enough APM. Built for developers.
Elixir, Erlang & BEAM conferences from Code Sync - join us in 2026!
Practical resources that improve the lives of professional developers.
**Building the future of software with AI, trust, and human connection.**
The deployment platform built for Elixir: PaaS ease, VPS control.
The team behind Membrane, Popcorn, LiveDebugger. Available for hire.
Courses that'll move you from confusion to "Aha, now I get it!"
Showing Posts 1 to 8- Show Best Posts
- Show All (oldest first)
- Show All (newest first)
krasenyp
I skimmed through the docs and the code and I suspect you’re encountering a bug. The new expectations are probably not merged correctly with the existing ones.
D4no0
This is extremely strange because this is not consistent, even though my calls in tests are always deterministic. Sometimes the test can fail on the second expectation and sometimes on the first one.
krasenyp
Maybe you can use a helper
Agentto register which expectation is called when and determine if there’s any logic to the behaviour you’re observing.D4no0
Nevermind, looks like I had a race condition in my processes
.
dimitarvp
What kind of? Could be useful for future readers.
mudasobwa
Note for the future readers: there was a bug with multiple lazy defined allowances until
v1.2.0which I fixed.D4no0
I am not sure how I can show an example, what I have are multiple genservers (some of them dependent on each-other) hitting multiple HTTP APIs.
I can confirm that with version 1.1.0, even with the race condition fixed in my application code, the tests still fail randomly as before, I’ve actually upgraded the dependency right in the middle of writing this topic so I might have experienced that bug too before upgrading. I did not mention it, because I didn’t saw bugfixes mentioned in changelogs of the new version. Thanks for the fix!
mudasobwa
Well, technically I brought this bug and then I fixed it.
The deferred allowance is my idea and my implementation, probably that is why it was buggy in the first place