# Suppress Stacktrace when a test fails

**URL:** <https://discourse.julialang.org/t/suppress-stacktrace-when-a-test-fails/19834>\
**Category:** General Usage\
**Created:** [January 20, 2019, 3:13am UTC](https://discourse.julialang.org/t/suppress-stacktrace-when-a-test-fails/19834 "2019-01-20T03:13:44Z")\
**Posts on this page:** 7\
**Page:** 1

<div class="post-metadata">

**Author:** ![curious](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/curious/32/7629_2.png) [@curious](https://discourse.julialang.org/u/curious)\
**Post date:** [January 20, 2019, 3:13am UTC](https://discourse.julialang.org/t/suppress-stacktrace-when-a-test-fails/19834/1 "2019-01-20T03:13:44Z")

</div>

Is there a way to suppress Stacktrace output when a test fails when using `@test` macro? I just want to know which test failed and what the expected output was and what the actual output was. The `@test` macro provides this information. But it also provides a lot of additional output which contains Stacktrace and even LoadError (which I am not sure why it is throwing). The additional output is distracting for the purpose that I want to use it for. So, is there a way to suppress it, that is not too difficult?

Thank you.

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**Author:** ![c42f](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/c42f/32/52842_2.png) [@c42f](https://discourse.julialang.org/u/c42f)\
**Post date:** [January 21, 2019, 12:19am UTC](https://discourse.julialang.org/t/suppress-stacktrace-when-a-test-fails/19834/2 "2019-01-21T00:19:52Z")

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This is not really controllable in a simple way (not by design, but simply by happenstance — `Test` could be improved in several ways; the way it collects and prints test results being one such way).

An easy/quick/horrible workaround is to monkey patch `record(::DefaultTestSet, ::Union{Fail, Error})`:

```julia
julia> using Test

julia> @testset "asdf" begin
           @test 0 == 1
       end
asdf: Test Failed at REPL[2]:2
  Expression: 0 == 1
   Evaluated: 0 == 1
Stacktrace:
 [1] top-level scope at REPL[2]:2
 [2] top-level scope at /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v1.1/Test/src/Test.jl:1083
 [3] top-level scope at REPL[2]:2
Test Summary: | Fail Total
asdf | 1 1
ERROR: Some tests did not pass: 0 passed, 1 failed, 0 errored, 0 broken.

julia> Test.eval(quote
       function record(ts::DefaultTestSet, t::Union{Fail, Error})
           if myid() == 1
               printstyled(ts.description, ": ", color=:white)
               # don't print for interrupted tests
               if !(t isa Error) || t.test_type != :test_interrupted
                   print(t)
                   # don't print the backtrace for Errors because it gets printed in the show
                   # method
                   if !isa(t, Error)
                       # Base.show_backtrace(stdout, scrub_backtrace(backtrace())) # Commented out
                   end
                   println()
               end
           end
           push!(ts.results, t)
           t, isa(t, Error) || backtrace()
       end
       end)

julia> @testset "asdf" begin
           @test 0 == 1
       end
asdf: Test Failed at REPL[4]:2
  Expression: 0 == 1
   Evaluated: 0 == 1
Test Summary: | Fail Total
asdf | 1 1
ERROR: Some tests did not pass: 0 passed, 1 failed, 0 errored, 0 broken.

```

An arguably saner alternative is to implement your own test set type. That’s a fair bit of work though.

The best option would be a big cleanup to how stdlib/Test deals with capturing and printing test results. That’s quite a lot of work.

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<div class="post-metadata">

**Author:** ![curious](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/curious/32/7629_2.png) [@curious](https://discourse.julialang.org/u/curious)\
**Post date:** [January 22, 2019, 8:08pm UTC](https://discourse.julialang.org/t/suppress-stacktrace-when-a-test-fails/19834/3 "2019-01-22T20:08:14Z")

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Thank you for the reply. Will take me some time to go through your reply. But it seems it is something I will let alone for now given the time constraints and my current level of Julia knowledge.

---

<div class="post-metadata">

**Author:** ![c42f](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/c42f/32/52842_2.png) [@c42f](https://discourse.julialang.org/u/c42f)\
**Post date:** [January 22, 2019, 10:07pm UTC](https://discourse.julialang.org/t/suppress-stacktrace-when-a-test-fails/19834/4 "2019-01-22T22:07:51Z")

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The short story: if you execute the `Test.eval` bit, this should do what you wanted (this very slightly modifies the code inside `stdlib/Test` at runtime). However, it depends on internal implementation details of `Test` and will probably stop working in a future Julia release.

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<div class="post-metadata">

**Author:** ![curious](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/curious/32/7629_2.png) [@curious](https://discourse.julialang.org/u/curious)\
**Post date:** [January 23, 2019, 3:38pm UTC](https://discourse.julialang.org/t/suppress-stacktrace-when-a-test-fails/19834/5 "2019-01-23T15:38:37Z")

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Thanks so much. I will try to see if that works. It it does, that would be great.

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**Author:** ![postylem](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/postylem/32/15639_2.png) [@postylem](https://discourse.julialang.org/u/postylem)\
**Post date:** [February 24, 2021, 3:11am UTC](https://discourse.julialang.org/t/suppress-stacktrace-when-a-test-fails/19834/6 "2021-02-24T03:11:43Z")

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Is there any news on this? This seems so useful, it would be nice to have a way of doing tests that gave clean output without stacktraces, when desired. I don’t understand what’s going on well enough to dig into it myself though.

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<div class="post-metadata">

**Author:** ![monty](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/monty/32/44234_2.png) [@monty](https://discourse.julialang.org/u/monty)\
**Post date:** [July 8, 2021, 4:36am UTC](https://discourse.julialang.org/t/suppress-stacktrace-when-a-test-fails/19834/7 "2021-07-08T04:36:31Z")

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I think this simple enough, easy enough, and clean enough

```julia
Test.eval(quote
	function record(ts::DefaultTestSet, t::Union{Fail, Error})
		push!(ts.results, t)
	end
end)

```