Unit and Functional Testing¶
Testing Base Julia¶
Julia is under rapid development and has an extensive test suite to
verify functionality across multiple platforms. If you build Julia
from source, you can run this test suite with make test
. In a
binary install, you can run the test suite using Base.runtests()
.
-
runtests
([tests=["all"][, numcores=iceil(CPU_CORES/2)]])¶ Run the Julia unit tests listed in
tests
, which can be either a string or an array of strings, usingnumcores
processors. (not exported)
Test Framework¶
The Test
module contains macros and functions related to testing.
A default handler is provided to run the tests, and a custom one can be
provided by the user by using the registerhandler()
function.
To use the default handler, the macro @test()
can be used directly:
julia> using Base.Test
julia> @test 1 == 1
julia> @test 1 == 0
ERROR: test failed: 1 == 0
in error at error.jl:21
in default_handler at test.jl:19
in do_test at test.jl:39
julia> @test error("This is what happens when a test fails")
ERROR: test error during error("This is what happens when a test fails")
This is what happens when a test fails
in error at error.jl:21
in anonymous at test.jl:62
in do_test at test.jl:37
As seen in the examples above, failures or errors will print the abstract syntax tree of the expression in question.
Another macro is provided to check if the given expression throws an exception of type extype
,
@test_throws()
:
julia> @test_throws ErrorException error("An error")
ErrorException("An error")
julia> @test_throws BoundsError error("An error")
ERROR: test failed: error("An error")
in error at error.jl:21
in default_handler at test.jl:19
in do_test_throws at test.jl:55
julia> @test_throws DomainError throw(DomainError())
DomainError()
julia> @test_throws DomainError throw(EOFError())
ERROR: test failed: throw(EOFError())
in error at error.jl:21
in default_handler at test.jl:19
in do_test_throws at test.jl:55
As floating-point values can be imprecise, you can perform approximate
equality checks using either @test a ≈ b
(where ≈
, typed via
tab completion of \approx
, is the isapprox
function) or use
the macros @test_approx_eq
macro (which differs from isapprox
in that it treats NaN values as equal and has a smaller default
tolerance) or @test_approx_eq_eps
(which takes an extra argument
indicating the relative tolerance):
julia> @test 1 ≈ 0.999999999
julia> @test 1 ≈ 0.999999
ERROR: test failed: 1 isapprox 0.999999
in expression: 1 ≈ 0.999999
in error at error.jl:21
in default_handler at test.jl:30
in do_test at test.jl:53
julia> @test_approx_eq 1. 0.999999999
ERROR: assertion failed: |1.0 - 0.999999999| < 2.220446049250313e-12
1.0 = 1.0
0.999999999 = 0.999999999
in test_approx_eq at test.jl:75
in test_approx_eq at test.jl:80
julia> @test_approx_eq 1. 0.9999999999999
julia> @test_approx_eq_eps 1. 0.999 1e-2
julia> @test_approx_eq_eps 1. 0.999 1e-3
ERROR: assertion failed: |1.0 - 0.999| <= 0.001
1.0 = 1.0
0.999 = 0.999
difference = 0.0010000000000000009 > 0.001
in error at error.jl:22
in test_approx_eq at test.jl:68
Handlers¶
A handler is a function defined for three kinds of arguments: Success
, Failure
, Error
:
# An example definition of a test handler
test_handler(r::Success) = nothing
test_handler(r::Failure) = error("test failed: $(r.expr)")
test_handler(r::Error) = rethrow(r)
A different handler can be used for a block (with with_handler()
):
julia> using Base.Test
julia> custom_handler(r::Test.Success) = println("Success on $(r.expr)")
custom_handler (generic function with 1 method)
julia> custom_handler(r::Test.Failure) = error("Error on custom handler: $(r.expr)")
custom_handler (generic function with 2 methods)
julia> custom_handler(r::Test.Error) = rethrow(r)
custom_handler (generic function with 3 methods)
julia> Test.with_handler(custom_handler) do
@test 1 == 1
@test 1 != 1
end
Success on :((1==1))
ERROR: Error on custom handler: :((1!=1))
in error at error.jl:21
in custom_handler at none:1
in do_test at test.jl:39
in anonymous at no file:3
in task_local_storage at task.jl:28
in with_handler at test.jl:24
The Success
and Failure
types include an additonal field, resultexpr
, which is a partially evaluated expression. For example, in a comparison it will contain an expression with the left and right sides evaluated.
Macros¶
-
@test
(ex)¶ Test the expression
ex
and calls the current handler to handle the result.
-
@test_throws
(extype, ex)¶ Test that the expression
ex
throws an exception of typeextype
and calls the current handler to handle the result.
-
@test_approx_eq
(a, b)¶ Test two floating point numbers
a
andb
for equality taking in account small numerical errors.
-
@test_approx_eq_eps
(a, b, tol)¶ Test two floating point numbers
a
andb
for equality taking in account a margin of tolerance given bytol
.