Merge pull request #2590 from nicoddemus/current-test-var

Introduce new PYTEST_CURRENT_TEST environment variable

Author: The-Compiler

_pytest/runner.py

@@ -2,6 +2,7 @@
 from __future__ import absolute_import, division, print_function
 
 import bdb
+import os
 import sys
 from time import time
 
@@ -91,9 +92,11 @@ def show_test_item(item):
         tw.write(' (fixtures used: {0})'.format(', '.join(used_fixtures)))
 
 def pytest_runtest_setup(item):
+    _update_current_test_var(item, 'setup')
     item.session._setupstate.prepare(item)
 
 def pytest_runtest_call(item):
+    _update_current_test_var(item, 'call')
     try:
         item.runtest()
     except Exception:
@@ -107,7 +110,23 @@ def pytest_runtest_call(item):
         raise
 
 def pytest_runtest_teardown(item, nextitem):
+    _update_current_test_var(item, 'teardown')
     item.session._setupstate.teardown_exact(item, nextitem)
+    _update_current_test_var(item, None)
+
+
+def _update_current_test_var(item, when):
+    """
+    Update PYTEST_CURRENT_TEST to reflect the current item and stage.
+
+    If ``when`` is None, delete PYTEST_CURRENT_TEST from the environment.
+    """
+    var_name = 'PYTEST_CURRENT_TEST'
+    if when:
+        os.environ[var_name] = '{0} ({1})'.format(item.nodeid, when)
+    else:
+        os.environ.pop(var_name)
+
 
 def pytest_report_teststatus(report):
     if report.when in ("setup", "teardown"):

changelog/2583.feature

@@ -0,0 +1,2 @@
+Introduce the ``PYTEST_CURRENT_TEST`` environment variable that is set with the ``nodeid`` and stage (``setup``, ``call`` and
+``teardown``) of the test being currently executed. See the `documentation <https://docs.pytest.org/en/latest/example/simple.html#pytest-current-test-environment-variable>`_ for more info.

doc/en/customize.rst

@@ -112,15 +112,27 @@ progress output, you can write it into a configuration file:
     # content of pytest.ini
     # (or tox.ini or setup.cfg)
     [pytest]
-    addopts = -rsxX -q
+    addopts = -ra -q
 
-Alternatively, you can set a PYTEST_ADDOPTS environment variable to add command
+Alternatively, you can set a ``PYTEST_ADDOPTS`` environment variable to add command
 line options while the environment is in use::
 
-    export PYTEST_ADDOPTS="-rsxX -q"
+    export PYTEST_ADDOPTS="-v"
 
-From now on, running ``pytest`` will add the specified options.
+Here's how the command-line is built in the presence of ``addopts`` or the environment variable::
 
+    <pytest.ini:addopts> $PYTEST_ADDOTPS <extra command-line arguments>
+
+So if the user executes in the command-line::
+
+    pytest -m slow
+
+The actual command line executed is::
+
+    pytest -ra -q -v -m slow
+
+Note that as usual for other command-line applications, in case of conflicting options the last one wins, so the example
+above will show verbose output because ``-v`` overwrites ``-q``.
 
 
 Builtin configuration file options

doc/en/example/simple.rst

@@ -761,6 +761,47 @@ and run it::
 You'll see that the fixture finalizers could use the precise reporting
 information.
 
+``PYTEST_CURRENT_TEST`` environment variable
+--------------------------------------------
+
+.. versionadded:: 3.2
+
+Sometimes a test session might get stuck and there might be no easy way to figure out
+which test got stuck, for example if pytest was run in quiet mode (``-q``) or you don't have access to the console
+output. This is particularly a problem if the problem helps only sporadically, the famous "flaky" kind of tests.
+
+``pytest`` sets a ``PYTEST_CURRENT_TEST`` environment variable when running tests, which can be inspected
+by process monitoring utilities or libraries like `psutil <https://pypi.python.org/pypi/psutil>`_ to discover which
+test got stuck if necessary:
+
+.. code-block:: python
+
+    import psutil
+
+    for pid in psutil.pids():
+        environ = psutil.Process(pid).environ()
+        if 'PYTEST_CURRENT_TEST' in environ:
+            print(f'pytest process {pid} running: {environ["PYTEST_CURRENT_TEST"]}')
+
+During the test session pytest will set ``PYTEST_CURRENT_TEST`` to the current test
+:ref:`nodeid <nodeids>` and the current stage, which can be ``setup``, ``call``
+and ``teardown``.
+
+For example, when running a single test function named ``test_foo`` from ``foo_module.py``,
+``PYTEST_CURRENT_TEST`` will be set to:
+
+#. ``foo_module.py::test_foo (setup)``
+#. ``foo_module.py::test_foo (call)``
+#. ``foo_module.py::test_foo (teardown)``
+
+In that order.
+
+.. note::
+
+    The contents of ``PYTEST_CURRENT_TEST`` is meant to be human readable and the actual format
+    can be changed between releases (even bug fixes) so it shouldn't be relied on for scripting
+    or automation.
+
 Freezing pytest 
 ---------------
 

doc/en/usage.rst

@@ -52,23 +52,64 @@ To stop the testing process after the first (N) failures::
 Specifying tests / selecting tests
 ---------------------------------------------------
 
-Several test run options::
-
-    pytest test_mod.py   # run tests in module
-    pytest somepath      # run all tests below somepath
-    pytest -k stringexpr # only run tests with names that match the
-                          # "string expression", e.g. "MyClass and not method"
-                          # will select TestMyClass.test_something
-                          # but not TestMyClass.test_method_simple
-    pytest test_mod.py::test_func  # only run tests that match the "node ID",
-                                    # e.g. "test_mod.py::test_func" will select
-                                    # only test_func in test_mod.py
-    pytest test_mod.py::TestClass::test_method  # run a single method in
-                                                 # a single class
-
-Import 'pkg' and use its filesystem location to find and run tests::
-
-    pytest --pyargs pkg # run all tests found below directory of pkg
+Pytest supports several ways to run and select tests from the command-line.
+
+**Run tests in a module**
+
+::
+
+    pytest test_mod.py
+
+**Run tests in a directory**
+
+::
+
+    pytest testing/
+
+**Run tests by keyword expressions**
+
+::
+
+    pytest -k "MyClass and not method"
+
+This will run tests which contain names that match the given *string expression*, which can
+include Python operators that use filenames, class names and function names as variables.
+The example above will run ``TestMyClass.test_something``  but not ``TestMyClass.test_method_simple``.
+
+.. _nodeids:
+
+**Run tests by node ids**
+
+Each collected test is assigned a unique ``nodeid`` which consist of the module filename followed
+by specifiers like class names, function names and parameters from parametrization, separated by ``::`` characters.
+
+To run a specific test within a module::
+
+    pytest test_mod.py::test_func
+
+
+Another example specifying a test method in the command line::
+
+    pytest test_mod.py::TestClass::test_method
+
+**Run tests by marker expressions**
+
+::
+
+    pytest -m slow
+
+Will run all tests which are decorated with the ``@pytest.mark.slow`` decorator.
+
+For more information see :ref:`marks <mark>`.
+
+**Run tests from packages**
+
+::
+
+    pytest --pyargs pkg.testing
+     
+This will import ``pkg.testing`` and use its filesystem location to find and run tests from.
+    
 
 Modifying Python traceback printing
 ----------------------------------------------

testing/test_runner.py

@@ -681,6 +681,8 @@ def test_store_except_info_on_eror():
     """
     # Simulate item that raises a specific exception
     class ItemThatRaises(object):
+        nodeid = 'item_that_raises'
+        
         def runtest(self):
             raise IndexError('TEST')
     try:
@@ -693,6 +695,31 @@ def runtest(self):
     assert sys.last_traceback
 
 
+def test_current_test_env_var(testdir, monkeypatch):
+    pytest_current_test_vars = []
+    monkeypatch.setattr(sys, 'pytest_current_test_vars', pytest_current_test_vars, raising=False)
+    testdir.makepyfile('''
+        import pytest
+        import sys
+        import os
+
+        @pytest.fixture
+        def fix():
+            sys.pytest_current_test_vars.append(('setup', os.environ['PYTEST_CURRENT_TEST']))
+            yield
+            sys.pytest_current_test_vars.append(('teardown', os.environ['PYTEST_CURRENT_TEST']))
+
+        def test(fix):
+            sys.pytest_current_test_vars.append(('call', os.environ['PYTEST_CURRENT_TEST']))
+    ''')
+    result = testdir.runpytest_inprocess()
+    assert result.ret == 0
+    test_id = 'test_current_test_env_var.py::test'
+    assert pytest_current_test_vars == [
+        ('setup', test_id + ' (setup)'), ('call', test_id + ' (call)'), ('teardown', test_id + ' (teardown)')]
+    assert 'PYTEST_CURRENT_TEST' not in os.environ
+
+
 class TestReportContents(object):
     """
     Test user-level API of ``TestReport`` objects.

tox.ini

@@ -49,9 +49,6 @@ commands=
 skipsdist=True
 usedevelop=True
 basepython = python2.7
-# needed to keep check-manifest working
-setenv =
-    SETUPTOOLS_SCM_PRETEND_VERSION=2.0.1
 deps =
     flake8
     # pygments required by rst-lint