Testing in Elixir

Testing in Elixir[edit]

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Testing is an essential part of software development, as it helps to ensure that the code behaves as expected and detects any potential bugs or issues. In Elixir, testing is made easy and efficient with the help of built-in tools and frameworks.

ExUnit[edit]

The primary testing framework in Elixir is ExUnit. ExUnit provides a simple and intuitive way to write tests for your Elixir code. With ExUnit, you can define test cases, write assertions, and run tests effortlessly.

Here is an example of a basic ExUnit test case:

```elixir defmodule MyTest do

 use ExUnit.Case

 test "addition" do
   result = 2 + 2
   assert result == 4
 end

end ```

To run tests using ExUnit, you can use the `mix test` command. ExUnit provides a mechanism for organizing and running tests efficiently, making it easy to maintain a comprehensive test suite for your Elixir projects.

Mocking and Stubbing[edit]

Elixir provides several libraries for mocking and stubbing dependencies in your tests. One popular library is `Mox`, which enables you to define mocks and stubs that can be used during testing.

With `Mox`, you can easily mock external dependencies and control their behavior in your tests. This allows you to isolate your code and test specific scenarios without relying on real external services or complex setups.

Here is an example of using `Mox` to mock a database connection:

```elixir defmodule MyTest do

 use ExUnit.Case
 import Mox

 test "database query" do
   db_mock = double(MyApp.Database)
   expect(db_mock, :query, fn _ -> [{1, "John"}, {2, "Jane"}] end)

   result = MyApp.query_database(db_mock)
   assert result == [{1, "John"}, {2, "Jane"}]
 end

end ```

Property-based Testing[edit]

In addition to traditional unit tests, Elixir also supports property-based testing through libraries like `ExCheck`. Property-based testing allows you to specify properties that should hold true for a range of inputs, automatically generating test cases to verify the properties.

With `ExCheck`, you can define properties using generators and combinators to model the desired behavior of your code. The library then generates random inputs, running tests to ensure the properties hold true.

Here is an example of property-based testing using `ExCheck`:

```elixir defmodule MyTest do

 use ExUnitProperties

 property "addition is commutative" do
   check all a <- integer, all b <- integer do
     assert a + b == b + a
   end
 end

end ```

Continuous Integration[edit]

To automate the execution of tests, you can integrate Elixir projects with popular continuous integration (CI) services. CI services like Jenkins, CircleCI, or Travis CI can be configured to run your test suite every time changes are pushed to your repository.

By integrating with a CI service, you can ensure that your tests are always up to date and run in a consistent environment. This helps catch any regressions or issues early on, allowing for faster feedback and faster development cycles.

References[edit]

ExUnit on GitHub Mox on GitHub ExCheck on GitHub

Testing in Elixir

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