diff --git a/HISTORY.rst b/HISTORY.rst
index d70cee6c9..c854ef80b 100644
--- a/HISTORY.rst
+++ b/HISTORY.rst
@@ -1,6 +1,6 @@
 *Bug tracker at https://github.com/giampaolo/psutil/issues*
 
-6.0.1 (IN DEVELOPMENT)
+6.1.0 (IN DEVELOPMENT)
 ======================
 
 XXXX-XX-XX
@@ -14,6 +14,10 @@ XXXX-XX-XX
   targets. They can be used to install dependencies meant for running tests and
   for local development. They can also be installed via ``pip install .[test]``
   and ``pip install .[dev]``.
+- 2456_: allow to run tests via ``python3 -m psutil.tests`` even if ``pytest``
+  module is not installed. This is useful for production environments that
+  don't have pytest installed, but still want to be able to test psutil
+  installation.
 
 **Bug fixes**
 
diff --git a/docs/DEVGUIDE.rst b/docs/DEVGUIDE.rst
index 456714603..563c9b883 100644
--- a/docs/DEVGUIDE.rst
+++ b/docs/DEVGUIDE.rst
@@ -18,6 +18,14 @@ Once you have a compiler installed run:
     make install
     make test
 
+- If you don't have the source code, and just want to test psutil installation.
+  This will work also if ``pytest`` module is not installed (e.g. production
+  environments) by using unittest's test runner:
+
+.. code-block:: bash
+
+    python3 -m psutil.tests
+
 - ``make`` (and the accompanying `Makefile`_) is the designated tool to build,
   install, run tests and do pretty much anything that involves development.
   This also includes Windows, meaning that you can run `make command` similarly
diff --git a/psutil/__init__.py b/psutil/__init__.py
index c1e038f3e..763a5f00e 100644
--- a/psutil/__init__.py
+++ b/psutil/__init__.py
@@ -214,7 +214,7 @@
 AF_LINK = _psplatform.AF_LINK
 
 __author__ = "Giampaolo Rodola'"
-__version__ = "6.0.1"
+__version__ = "6.1.0"
 version_info = tuple([int(num) for num in __version__.split('.')])
 
 _timer = getattr(time, 'monotonic', time.time)
diff --git a/psutil/tests/README.rst b/psutil/tests/README.rst
index 5c7336fb0..8e5b6e7d8 100644
--- a/psutil/tests/README.rst
+++ b/psutil/tests/README.rst
@@ -1,40 +1,35 @@
 Instructions for running tests
 ==============================
 
-Setup:
+There are 2 ways of running tests. If you have the source code:
 
 .. code-block:: bash
 
     make install-pydeps-test  # install pytest
+    make test
 
-There are two ways of running tests. As a "user", if psutil is already
-installed and you just want to test it works on your system:
+If you don't have the source code, and just want to test psutil installation.
+This will work also if ``pytest`` module is not installed (e.g. production
+environments) by using unittest's test runner:
 
 .. code-block:: bash
 
     python -m psutil.tests
 
-As a "developer", if you have a copy of the source code and you're working on
-it:
-
-.. code-block:: bash
-
-    make test
-
-You can run tests in parallel with:
+To run tests in parallel (faster):
 
 .. code-block:: bash
 
     make test-parallel
 
-You can run a specific test with:
+Run a specific test:
 
 .. code-block:: bash
 
     make test ARGS=psutil.tests.test_system.TestDiskAPIs
 
-You can run memory leak tests with:
+Test C extension memory leaks:
 
 .. code-block:: bash
 
-    make test-parallel
+    make test-memleaks
diff --git a/psutil/tests/__init__.py b/psutil/tests/__init__.py
index e4667ab69..dd31392c0 100644
--- a/psutil/tests/__init__.py
+++ b/psutil/tests/__init__.py
@@ -36,7 +36,11 @@
 from socket import AF_INET6
 from socket import SOCK_STREAM
 
-import pytest
+
+try:
+    import pytest
+except ImportError:
+    pytest = None
 
 import psutil
 from psutil import AIX
@@ -71,6 +75,8 @@
 if PY3:
     import enum
 else:
+    import unittest2 as unittest
+
     enum = None
 
 if POSIX:
@@ -913,6 +919,76 @@ def get_testfn(suffix="", dir=None):
 # ===================================================================
 
 
+class fake_pytest:
+    """A class that mimics some basic pytest APIs. This is meant for
+    when unit tests are run in production, where pytest may not be
+    installed. Still, the user can test psutil installation via:
+
+        $ python3 -m psutil.tests
+    """
+
+    @staticmethod
+    def main(*args, **kw):  # noqa ARG004
+        """Mimics pytest.main(). It has the same effect as running
+        `python3 -m unittest -v` from the project root directory.
+        """
+        suite = unittest.TestLoader().discover(HERE)
+        unittest.TextTestRunner(verbosity=2).run(suite)
+        warnings.warn(
+            "Fake pytest module was used. Test results may be inaccurate.",
+            UserWarning,
+            stacklevel=1,
+        )
+        return suite
+
+    @staticmethod
+    def raises(exc, match=None):
+        """Mimics `pytest.raises`."""
+
+        class ExceptionInfo:
+            _exc = None
+
+            @property
+            def value(self):
+                return self._exc
+
+        @contextlib.contextmanager
+        def context(exc, match=None):
+            einfo = ExceptionInfo()
+            try:
+                yield einfo
+            except exc as err:
+                if match and not re.search(match, str(err)):
+                    msg = '"{}" does not match "{}"'.format(match, str(err))
+                    raise AssertionError(msg)
+                einfo._exc = err
+            else:
+                raise AssertionError("%r not raised" % exc)
+
+        return context(exc, match=match)
+
+    @staticmethod
+    def warns(warning, match=None):
+        """Mimics `pytest.warns`."""
+        if match:
+            return unittest.TestCase().assertWarnsRegex(warning, match)
+        return unittest.TestCase().assertWarns(warning)
+
+    class mark:
+        class xdist_group:
+            """Mimics `@pytest.mark.xdist_group` decorator (no-op)."""
+
+            def __init__(self, name=None):
+                pass
+
+            def __call__(self, cls_or_meth):
+                return cls_or_meth
+
+
+if pytest is None:
+    pytest = fake_pytest
+
+
 class TestCase(unittest.TestCase):
     # ...otherwise multiprocessing.Pool complains
     if not PY3:
diff --git a/psutil/tests/__main__.py b/psutil/tests/__main__.py
index f43b751f9..ce6fc24c7 100644
--- a/psutil/tests/__main__.py
+++ b/psutil/tests/__main__.py
@@ -6,7 +6,7 @@
 $ python -m psutil.tests.
 """
 
-import pytest
+from psutil.tests import pytest
 
 
 pytest.main(["-v", "-s", "--tb=short"])
diff --git a/psutil/tests/test_bsd.py b/psutil/tests/test_bsd.py
index 13c877460..3af505b60 100755
--- a/psutil/tests/test_bsd.py
+++ b/psutil/tests/test_bsd.py
@@ -16,8 +16,6 @@
 import time
 import unittest
 
-import pytest
-
 import psutil
 from psutil import BSD
 from psutil import FREEBSD
@@ -26,6 +24,7 @@
 from psutil.tests import HAS_BATTERY
 from psutil.tests import TOLERANCE_SYS_MEM
 from psutil.tests import PsutilTestCase
+from psutil.tests import pytest
 from psutil.tests import retry_on_failure
 from psutil.tests import sh
 from psutil.tests import spawn_testproc
diff --git a/psutil/tests/test_connections.py b/psutil/tests/test_connections.py
index 783bf8145..7f29900b2 100755
--- a/psutil/tests/test_connections.py
+++ b/psutil/tests/test_connections.py
@@ -16,8 +16,6 @@
 from socket import SOCK_DGRAM
 from socket import SOCK_STREAM
 
-import pytest
-
 import psutil
 from psutil import FREEBSD
 from psutil import LINUX
@@ -38,6 +36,7 @@
 from psutil.tests import check_connection_ntuple
 from psutil.tests import create_sockets
 from psutil.tests import filter_proc_net_connections
+from psutil.tests import pytest
 from psutil.tests import reap_children
 from psutil.tests import retry_on_failure
 from psutil.tests import skip_on_access_denied
diff --git a/psutil/tests/test_linux.py b/psutil/tests/test_linux.py
index aa51739b1..788fe9914 100755
--- a/psutil/tests/test_linux.py
+++ b/psutil/tests/test_linux.py
@@ -23,8 +23,6 @@
 import unittest
 import warnings
 
-import pytest
-
 import psutil
 from psutil import LINUX
 from psutil._compat import PY3
@@ -46,6 +44,7 @@
 from psutil.tests import ThreadTask
 from psutil.tests import call_until
 from psutil.tests import mock
+from psutil.tests import pytest
 from psutil.tests import reload_module
 from psutil.tests import retry_on_failure
 from psutil.tests import safe_rmpath
diff --git a/psutil/tests/test_misc.py b/psutil/tests/test_misc.py
index adafea947..8ddaec28a 100755
--- a/psutil/tests/test_misc.py
+++ b/psutil/tests/test_misc.py
@@ -18,8 +18,6 @@
 import sys
 import unittest
 
-import pytest
-
 import psutil
 import psutil.tests
 from psutil import POSIX
@@ -50,6 +48,7 @@
 from psutil.tests import PsutilTestCase
 from psutil.tests import mock
 from psutil.tests import process_namespace
+from psutil.tests import pytest
 from psutil.tests import reload_module
 from psutil.tests import sh
 from psutil.tests import system_namespace
@@ -634,26 +633,29 @@ def test_debug(self):
         else:
             from StringIO import StringIO
 
-        with redirect_stderr(StringIO()) as f:
-            debug("hello")
-            sys.stderr.flush()
+        with mock.patch.object(psutil._common, "PSUTIL_DEBUG", True):
+            with redirect_stderr(StringIO()) as f:
+                debug("hello")
+                sys.stderr.flush()
         msg = f.getvalue()
         assert msg.startswith("psutil-debug"), msg
         assert "hello" in msg
         assert __file__.replace('.pyc', '.py') in msg
 
         # supposed to use repr(exc)
-        with redirect_stderr(StringIO()) as f:
-            debug(ValueError("this is an error"))
+        with mock.patch.object(psutil._common, "PSUTIL_DEBUG", True):
+            with redirect_stderr(StringIO()) as f:
+                debug(ValueError("this is an error"))
         msg = f.getvalue()
         assert "ignoring ValueError" in msg
         assert "'this is an error'" in msg
 
         # supposed to use str(exc), because of extra info about file name
-        with redirect_stderr(StringIO()) as f:
-            exc = OSError(2, "no such file")
-            exc.filename = "/foo"
-            debug(exc)
+        with mock.patch.object(psutil._common, "PSUTIL_DEBUG", True):
+            with redirect_stderr(StringIO()) as f:
+                exc = OSError(2, "no such file")
+                exc.filename = "/foo"
+                debug(exc)
         msg = f.getvalue()
         assert "no such file" in msg
         assert "/foo" in msg
diff --git a/psutil/tests/test_posix.py b/psutil/tests/test_posix.py
index dd2d179dd..5c2c86c9e 100755
--- a/psutil/tests/test_posix.py
+++ b/psutil/tests/test_posix.py
@@ -15,8 +15,6 @@
 import time
 import unittest
 
-import pytest
-
 import psutil
 from psutil import AIX
 from psutil import BSD
@@ -31,6 +29,7 @@
 from psutil.tests import QEMU_USER
 from psutil.tests import PsutilTestCase
 from psutil.tests import mock
+from psutil.tests import pytest
 from psutil.tests import retry_on_failure
 from psutil.tests import sh
 from psutil.tests import skip_on_access_denied
diff --git a/psutil/tests/test_process.py b/psutil/tests/test_process.py
index a339ac2d3..b3e6569ee 100755
--- a/psutil/tests/test_process.py
+++ b/psutil/tests/test_process.py
@@ -21,8 +21,6 @@
 import types
 import unittest
 
-import pytest
-
 import psutil
 from psutil import AIX
 from psutil import BSD
@@ -65,6 +63,7 @@
 from psutil.tests import create_py_exe
 from psutil.tests import mock
 from psutil.tests import process_namespace
+from psutil.tests import pytest
 from psutil.tests import reap_children
 from psutil.tests import retry_on_failure
 from psutil.tests import sh
@@ -1452,8 +1451,9 @@ def test_reused_pid(self):
 
         # make sure is_running() removed PID from process_iter()
         # internal cache
-        with redirect_stderr(StringIO()) as f:
-            list(psutil.process_iter())
+        with mock.patch.object(psutil._common, "PSUTIL_DEBUG", True):
+            with redirect_stderr(StringIO()) as f:
+                list(psutil.process_iter())
         assert (
             "refreshing Process instance for reused PID %s" % p.pid
             in f.getvalue()
diff --git a/psutil/tests/test_process_all.py b/psutil/tests/test_process_all.py
index a6025390e..1550046ba 100755
--- a/psutil/tests/test_process_all.py
+++ b/psutil/tests/test_process_all.py
@@ -16,8 +16,6 @@
 import time
 import traceback
 
-import pytest
-
 import psutil
 from psutil import AIX
 from psutil import BSD
@@ -43,6 +41,7 @@
 from psutil.tests import is_namedtuple
 from psutil.tests import is_win_secure_system_proc
 from psutil.tests import process_namespace
+from psutil.tests import pytest
 
 
 # Cuts the time in half, but (e.g.) on macOS the process pool stays
diff --git a/psutil/tests/test_system.py b/psutil/tests/test_system.py
index 7403326bf..298d2d9e4 100755
--- a/psutil/tests/test_system.py
+++ b/psutil/tests/test_system.py
@@ -19,8 +19,6 @@
 import time
 import unittest
 
-import pytest
-
 import psutil
 from psutil import AIX
 from psutil import BSD
@@ -56,6 +54,7 @@
 from psutil.tests import check_net_address
 from psutil.tests import enum
 from psutil.tests import mock
+from psutil.tests import pytest
 from psutil.tests import retry_on_failure
 
 
diff --git a/psutil/tests/test_testutils.py b/psutil/tests/test_testutils.py
index d74df153a..7293aa010 100755
--- a/psutil/tests/test_testutils.py
+++ b/psutil/tests/test_testutils.py
@@ -14,9 +14,9 @@
 import socket
 import stat
 import subprocess
+import textwrap
 import unittest
-
-import pytest
+import warnings
 
 import psutil
 import psutil.tests
@@ -29,6 +29,7 @@
 from psutil.tests import CI_TESTING
 from psutil.tests import COVERAGE
 from psutil.tests import HAS_NET_CONNECTIONS_UNIX
+from psutil.tests import HERE
 from psutil.tests import PYTHON_EXE
 from psutil.tests import PYTHON_EXE_ENV
 from psutil.tests import PsutilTestCase
@@ -38,11 +39,13 @@
 from psutil.tests import call_until
 from psutil.tests import chdir
 from psutil.tests import create_sockets
+from psutil.tests import fake_pytest
 from psutil.tests import filter_proc_net_connections
 from psutil.tests import get_free_port
 from psutil.tests import is_namedtuple
 from psutil.tests import mock
 from psutil.tests import process_namespace
+from psutil.tests import pytest
 from psutil.tests import reap_children
 from psutil.tests import retry
 from psutil.tests import retry_on_failure
@@ -167,6 +170,7 @@ def test_wait_for_file_no_delete(self):
 
     def test_call_until(self):
         call_until(lambda: 1)
+        # TODO: test for timeout
 
 
 class TestFSTestUtils(PsutilTestCase):
@@ -444,6 +448,85 @@ def fun_2():
             self.execute_w_exc(ZeroDivisionError, fun_2)
 
 
+class TestFakePytest(PsutilTestCase):
+    def test_raises(self):
+        with fake_pytest.raises(ZeroDivisionError) as cm:
+            1 / 0  # noqa
+        assert isinstance(cm.value, ZeroDivisionError)
+
+        with fake_pytest.raises(ValueError, match="foo") as cm:
+            raise ValueError("foo")
+
+        try:
+            with fake_pytest.raises(ValueError, match="foo") as cm:
+                raise ValueError("bar")
+        except AssertionError as err:
+            assert str(err) == '"foo" does not match "bar"'
+        else:
+            raise self.fail("exception not raised")
+
+    def test_mark(self):
+        @fake_pytest.mark.xdist_group(name="serial")
+        def foo():
+            return 1
+
+        assert foo() == 1
+
+        @fake_pytest.mark.xdist_group(name="serial")
+        class Foo:
+            def bar(self):
+                return 1
+
+        assert Foo().bar() == 1
+
+    def test_main(self):
+        tmpdir = self.get_testfn(dir=HERE)
+        os.mkdir(tmpdir)
+        with open(os.path.join(tmpdir, "__init__.py"), "w"):
+            pass
+        with open(os.path.join(tmpdir, "test_file.py"), "w") as f:
+            f.write(textwrap.dedent("""\
+                import unittest
+
+                class TestCase(unittest.TestCase):
+                    def test_passed(self):
+                        pass
+                """).lstrip())
+        with mock.patch.object(psutil.tests, "HERE", tmpdir):
+            with self.assertWarnsRegex(
+                UserWarning, "Fake pytest module was used"
+            ):
+                suite = fake_pytest.main()
+                assert suite.countTestCases() == 1
+
+    def test_warns(self):
+        # success
+        with fake_pytest.warns(UserWarning):
+            warnings.warn("foo", UserWarning, stacklevel=1)
+
+        # failure
+        try:
+            with fake_pytest.warns(UserWarning):
+                warnings.warn("foo", DeprecationWarning, stacklevel=1)
+        except AssertionError:
+            pass
+        else:
+            raise self.fail("exception not raised")
+
+        # match success
+        with fake_pytest.warns(UserWarning, match="foo"):
+            warnings.warn("foo", UserWarning, stacklevel=1)
+
+        # match failure
+        try:
+            with fake_pytest.warns(UserWarning, match="foo"):
+                warnings.warn("bar", UserWarning, stacklevel=1)
+        except AssertionError:
+            pass
+        else:
+            raise self.fail("exception not raised")
+
+
 class TestTestingUtils(PsutilTestCase):
     def test_process_namespace(self):
         p = psutil.Process()
diff --git a/psutil/tests/test_unicode.py b/psutil/tests/test_unicode.py
index 9177df5d7..cc7a5475b 100755
--- a/psutil/tests/test_unicode.py
+++ b/psutil/tests/test_unicode.py
@@ -79,8 +79,6 @@
 import warnings
 from contextlib import closing
 
-import pytest
-
 import psutil
 from psutil import BSD
 from psutil import POSIX
@@ -103,6 +101,7 @@
 from psutil.tests import copyload_shared_lib
 from psutil.tests import create_py_exe
 from psutil.tests import get_testfn
+from psutil.tests import pytest
 from psutil.tests import safe_mkdir
 from psutil.tests import safe_rmpath
 from psutil.tests import skip_on_access_denied
diff --git a/psutil/tests/test_windows.py b/psutil/tests/test_windows.py
index 0a2683dd2..7b5ba7ba1 100755
--- a/psutil/tests/test_windows.py
+++ b/psutil/tests/test_windows.py
@@ -20,8 +20,6 @@
 import unittest
 import warnings
 
-import pytest
-
 import psutil
 from psutil import WINDOWS
 from psutil._compat import FileNotFoundError
@@ -37,6 +35,7 @@
 from psutil.tests import TOLERANCE_SYS_MEM
 from psutil.tests import PsutilTestCase
 from psutil.tests import mock
+from psutil.tests import pytest
 from psutil.tests import retry_on_failure
 from psutil.tests import sh
 from psutil.tests import spawn_testproc
diff --git a/setup.py b/setup.py
index fb36da0bc..949716a5b 100755
--- a/setup.py
+++ b/setup.py
@@ -80,6 +80,7 @@
         "pytest-xdist",
         "pytest==4.6.11",
         "setuptools",
+        "unittest2",
     ]
 if WINDOWS and not PYPY:
     TEST_DEPS.append("pywin32")