Adding tests
Overview
Teaching: 10 min
Exercises: 30 minQuestions
What are unit tests?
How are tests organized in Julia?
Objectives
Learn to create unit tests and test-sets using the
Test
standard library
Unit tests
Now that Melissa has released her first package she fears that future changes will impact the existing functionality of her package. This can be prevented by adding tests to her package.
Looking at the structure of other packages Melissa figured out that tests
usually go in a separate test
folder next to the src
folder.
This should contain a runtests.jl
file.
The standard library Test
provides the functionality for writing tests:
namely, the macros @test
and @testset
.
@test
can be used to test a single equality, such as
using Test
@test 1 + 1 == 2
Several tests can be grouped in a test-set with a descriptive name
using Test
@testset "Test arithmetic equalities" begin
@test 1 + 1 == 2
end
With this Melissa can run her test using the pkg mode of the REPL:
(MelissasModule) pkg> test
Test specific dependencies
Melissa needed to add Test
to her package in order to run the code above, but
actually Test
is not needed for her package other than testing.
Thus it is possible to move the Test
entry in the Project.toml
file from
[deps]
to an [extras]
section and then add another entry:
[targets]
test = ["Test"]
Check out the sample project file for a complete example.
Create a test for MelissasModule
Create a test that ensures that
shoot_distance
returns a value that is betweentarget - ε
andtarget + ε
.Solution
using MelissasModule using Test @testset "Test hitting target" begin imprecise_trebuchet = Trebuchet(500.0, 0.25pi) environment = Environment(5, 100) precise_trebuchet = aim(imprecise_trebuchet, environment) @test 100 - 0.1 <= shoot_distance(precise_trebuchet, environment) <= 100 + 0.1 # default ε is 0.1 end
Key Points
Tests are important