What's the difference between @assert and @test?

[Ismael VC]

Hello guys!

I just had someone ask me this question and I didn't know what to answer him, example:

julia> using Base.Test

julia> @test 1 == 1

julia> @test 1 == 3

ERROR: test failed: 1 == 3

 in error at error.jl:21 (repeats 2 times)

julia> @assert 1 == 1

julia> @assert 1 == 3

ERROR: assertion failed: 1 == 3

 in error at error.jl:21 (repeats 2 times)

I fail to see the difference, besides that `@test` conveys the idea of "testing". 

Even the error message is even the same:  `in error at error.jl:21 (repeats 2 times)`

Thanks!

[Ivar Nesje]

Good question!

In 0.4 the printing for @test has been improved quite significantly to display the values of variables.

julia> a,b = 1,2

julia> @test a==b 
ERROR: test failed: (1 == 2)
in expression: a == b 
in error at error.jl:19
in default_handler at test.jl:27
in do_test at test.jl:50

julia> @assert a==b
ERROR: AssertionError: a == b

There is some discussion in #10614 about means to disable assertions, so there is a conceptual difference in that assertions is used inside a program to test for invalid inputs to functions, but tests are usually runned externally to see that functions work correctly for different outputs.

Regards

Ivar

[Ismael VC]

Thank you very much Ivar, that makes sense.