Documentation about Mercurial support

docs/source/contributing/tasks.md

@@ -23,6 +23,10 @@ If you want to run a specific test, you can do so with:
 py.test -s tests/<path-to-test>
 ```
 
+To skip the tests related to Mercurial repositories (to avoid to install
+Mercurial or hg-evolve), one can use the environment variables
+``REPO2DOCKER_SKIP_HG_TESTS`` or ``REPO2DOCKER_SKIP_HG_EVOLVE_TESTS``.
+
 ### Troubleshooting Tests
 
 Some of the tests have non-python requirements for your development machine. They are:

docs/source/install.rst

@@ -22,6 +22,17 @@ The `BinderHub <https://binderhub.readthedocs.io/>`_ helm chart uses version
 `helm chart <https://github.com/jupyterhub/binderhub/blob/master/helm-chart/binderhub/values.yaml#L167>`_
 for more details.
 
+Optional: Mercurial
+-------------------
+
+For `Mercurial <https://www.mercurial-scm.org>`_ repositories, `Mercurial needs
+to be installed <https://www.mercurial-scm.org/download>`_. For support of
+`Mercurial topics
+<https://www.mercurial-scm.org/doc/evolution/tutorials/topic-tutorial.html>`_,
+also install `hg-evolve <https://www.mercurial-scm.org/doc/evolution/>`_ which
+provides the topic extension (however, no need to explicitly enable it in a
+Mercurial configuration file).
+
 Installing with ``pip``
 -----------------------
 

tests/unit/contentproviders/test_mercurial.py

@@ -29,6 +29,11 @@ if SKIP_HG_EVOLVE:
 
 @skip_if_no_hg_tests
 def test_if_mercurial_is_available():
+    """
+    To skip the tests related to Mercurial repositories (to avoid to install
+    Mercurial), one can use the environment variable
+    REPO2DOCKER_SKIP_HG_TESTS.
+    """
     subprocess.check_output(["hg", "version"])
 
 
@@ -134,6 +139,10 @@ def test_bad_ref(hg_repo_with_content):
 def test_ref_topic(hg_repo_with_content):
     """
     Test trying to update to a topic
+
+    To skip this test (to avoid to install hg-evolve), one can use the
+    environment variable REPO2DOCKER_SKIP_HG_EVOLVE_TESTS.
+
     """
     upstream, node_id = hg_repo_with_content
     node_id = subprocess.Popen(