View Source JUnitFormatter

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A simple ExUnit Formatter that collects test results and generates an XML report in JUnit format. This is intended to be used by tools that can produce a graphical report, mainly targeted at Jenkins and its support for JUnit.

The report is generated in Mix.Project.app_path folder with a default filename of test-junit-report.xml. It can be configured through application configuration on the key report_file (application :junit_formatter).

Versions 3+ require minimum Elixir version to be 1.5+. For older releases, please use version 2.2 of this library.


First, add JUnitFormatter to the dependencies in your mix.exs:

  defp deps do
      {:junit_formatter, "~> 3.4", only: [:test]}

Next, add JUnitFormatter to your ExUnit configuration in test/test_helper.exs file. It should look like this:

ExUnit.configure formatters: [JUnitFormatter]

If you want to keep using the default formatter alongside the JUnitFormatter your test/test_helper.exs file should look like this:

ExUnit.configure formatters: [JUnitFormatter, ExUnit.CLIFormatter]

Then run your tests like normal:


Finished in 0.1 seconds (0.07s on load, 0.08s on tests)
4 tests, 0 failures

Randomized with seed 600810

The JUnit style XML report for this project looks like this:

<?xml version="1.0"?>
	<testsuite errors="0" failures="0" name="Elixir.FormatterTest" tests="4" time="82086">
		<testcase classname="Elixir.FormatterTest" name="test it counts raises as failures" time="16805"/>
		<testcase classname="Elixir.FormatterTest" name="test that an invalid test generates a proper report" time="16463"/>
		<testcase classname="Elixir.FormatterTest" name="test that a valid test generates a proper report" time="16328"/>
		<testcase classname="Elixir.FormatterTest" name="test valid and invalid tests generates a proper report" time="32490"/>

Note: This example has been reformatted for readability.


JUnitFormatter accepts 6 options that can be passed in config.exs (or equivalent environment configuration for tests):

  • print_report_file (boolean - default false): tells formatter if you want to see the path where the file is being written to in the console. This might help you debug where the file is. By default it writes the report to the Mix.Project.app_path folder. This ensures compatibility with umbrella apps.
  • report_file (binary - default "test-junit-report.xml"): the name of the file to write to. It must contain the extension. 99% of the time you will want the extension to be .xml, but if you don't you can pass any extension (though the contents of the file will be an XML document).
  • report_dir (binary - default Mix.Project.app_path()): the directory to which the formatter will write the report. Do not end it with a slash. IMPORTANT!! JUnitFormatter will NOT, by default, create the directory. If you are pointing to a directory that is outside _build then you can set the automatic_create_dir? option.
  • prepend_project_name? (boolean - default false): tells if the report file should have the name of the project as a prefix. See the "Umbrella" part of the documentation.
  • use_project_subdirectory? (boolean - default false): determines if the report file should be put into a subdirectory under report_dir named according to the project. If you set this then automatic_create_dir? will also be set to true. See the "Umbrella" part of the documentation.
  • include_filename? (boolean - default false): dictates whether <testcase>s in the XML report should include a "file" attribute of the relative path to the file of the test. Note that this defaults to false because not all JUnit ingesters will accept a file attribute.
  • include_file_line? (boolean - default false): only has effect when include_filename? is true. Dictates whether file attribute should include line of the test after a colon (e.g. test/file_test.exs:123).
  • automatic_create_dir? (boolean - default false): create a directory that defined in report_dir before writing report files.
  • project_dir (string - default nil). Specifies which directory the test file paths should be relative to within the XML. If unset or nil, the path to the test file is calculated relative to the current working directory.

Example configuration:

config :junit_formatter,
  report_file: "report_file_test.xml",
  report_dir: "/tmp",
  print_report_file: true,
  prepend_project_name?: true,
  include_filename?: true

This would generate the report at: /tmp/myapp-report_file_test.xml.

Umbrella projects

JUnitFormatter works with umbrella projects too. By default, it will generate the XML report on each sub-project build folder. So, as an example, if you have two apps (my-app and another) it will generate the following reports:

  • _build/test/lib/my_app/report_file.xml
  • _build/test/lib/another/report_file.xml

This works without any extra configuration. There are times, though, where you want to customize the directory where the reports are generated. Let's say you add this configuration:

config :junit_formatter,
  report_dir: "/tmp"

Then, while running in an umbrella project, the first sub-project will run and generate a report file the following path:

  • /tmp/report_file.xml

The next one will do the same OVERRIDING the first one. So, in order to avoid this, you can use the configuration option prepend_project_name? so that the result would be:

  • /tmp/my_app-report_file.xml
  • /tmp/another-report_file.xml

If you want to use a consistent report filename, and instead place the reports under a subdirectory per application, then set the use_project_subdirectory? configuration flag to true. Using this configuration would result in the following file layout:

  • /tmp/my_app/report_file.xml
  • /tmp/another/report_file.xml

If you want to specify the paths to the test files in the report relative to the root of the umbrella project, not the individual application, then set project_dir. In your umbrella configuration file, at config/test.exs, if you set the following configuration:

config :junit_formatter,
  project_dir: Path.expand("..", __DIR__)

Then in your report, a test file within your umbrella at apps/my_app/test/my_app_test.exs will be specified within the report as apps/my_app/test/my_app_test.exs. If you leave project_dir unset it would instead be specified as test/my_app_test.exs.

Integrating on CI systems

Most CIs have a way for uploading test reports. This is a nice way to understand what failed on your build. Most of them use the JUnit report file format to provide this feature.

  • CircleCI example configuration provides JUnit reports integration. For umbrella projects, if you set use_project_subdirectory?: true then CircleCI will provide reports per application. It is also advisable to set project_dir for umbrella projects so that files will be reported with their full path.


This project is available under Apache Public License version 2.0. See LICENSE.