Julia Language Unit Testing Testing Exceptions
Example
Exceptions encountered while running a test will fail the test, and if the test is not in a test set, terminate the test engine. Usually, this is a good thing, because in most situations exceptions are not the desired result. But sometimes, one wants to test specifically that a certain exception is raised. The @test_throws macro facilitates this.
julia> @test_throws BoundsError [1, 2, 3][4]
Test Passed
Expression: ([1,2,3])[4]
Thrown: BoundsError
If the wrong exception is thrown, @test_throws will still fail:
julia> @test_throws TypeError [1, 2, 3][4]
Test Failed
Expression: ([1,2,3])[4]
Expected: TypeError
Thrown: BoundsError
ERROR: There was an error during testing
in record(::Base.Test.FallbackTestSet, ::Base.Test.Fail) at ./test.jl:397
in do_test_throws(::Base.Test.Threw, ::Expr, ::Type{T}) at ./test.jl:329
and if no exception is thrown, @test_throws will fail also:
julia> @test_throws BoundsError [1, 2, 3, 4][4]
Test Failed
Expression: ([1,2,3,4])[4]
Expected: BoundsError
No exception thrown
ERROR: There was an error during testing
in record(::Base.Test.FallbackTestSet, ::Base.Test.Fail) at ./test.jl:397
in do_test_throws(::Base.Test.Returned, ::Expr, ::Type{T}) at ./test.jl:329
