Remove several test dependencies

* oslotest

  We are using just one fixture class(with only one useful code-line) from
  oslotest library. To reduce inheritors and simplify readability of the
  code, let's remove oslotest dependency.

  NOTE: coverage job will fail at master change with trying to import
        oslotest. To fix this issue oslotest is temporary added to `cover`
        tox env and will be removed in follow-up change

* testscenarios

  We do not use this dependency now (or even ever?!)

* coverage

  This library was used before we switched to pytest. Now, all we need
  is pytest-cov

Change-Id: Id0d52f928e067ced5bf4613c291019529b43fbbf

requirements.txt

@@ -10,6 +10,7 @@ jsonschema>=2.6.0,<3.0.0                               # MIT
 morph                                                  # GPLv3+
 netaddr>=0.7.18                                        # BSD
 oslo.config>=5.1.0                                     # Apache Software License
+# do not forget to remove `testresources` from test-requirements. it is a dependency of oslo.db for tests
 oslo.db>=4.27.0                                        # Apache Software License
 oslo.log>=3.36.0                                       # Apache Software License
 paramiko>=2.0.0                                        # LGPL

test-requirements.txt

@@ -12,7 +12,6 @@ pytest-html>=1.10.0                                    # Mozilla Public License
 # py.test xdist plugin for distributed testing and loop-on-failing modes
 pytest-xdist                                           # MIT
 
-coverage>=4.0,!=4.4                                    # Apache License, Version 2.0
 ddt>=1.0.1                                             # UNKNOWN
 mock>=2.0.0                                            # UNKNOWN
 python-dateutil>=2.4.2                                 # Simplified BSD
@@ -20,7 +19,5 @@ testtools>=2.2.0                                       # UNKNOWN
 
 sphinx>=1.6.2,!=1.6.6                                  # BSD
 oslosphinx>=4.7.0                                      # Apache Software License
-oslotest>=3.2.0                                        # Apache Software License
 
 testresources>=2.0.0                                   # UNKNOWN
-testscenarios>=0.4                                     # UNKNOWN

tests/unit/test.py

@@ -14,11 +14,12 @@
 #    under the License.
 
 import fixtures
+from fixtures._fixtures.tempdir import TempDir
 import os
 import uuid
 
 import mock
-from oslotest import base
+import testtools
 
 from rally.common import cfg
 from rally.common import db
@@ -26,6 +27,17 @@ from rally import plugins
 from tests.unit import fakes
 
 
+class TempHomeDir(TempDir):
+    """Create a temporary directory and set it as $HOME
+
+    :ivar path: the path of the temporary directory.
+    """
+
+    def _setUp(self):
+        super(TempHomeDir, self)._setUp()
+        self.useFixture(fixtures.EnvironmentVariable("HOME", self.path))
+
+
 class DatabaseFixture(cfg.fixture.Config):
     """Create clean DB before starting test."""
     def setUp(self):
@@ -37,13 +49,23 @@ class DatabaseFixture(cfg.fixture.Config):
         db.schema.schema_create()
 
 
-class TestCase(base.BaseTestCase):
+class TestCase(testtools.TestCase):
     """Test case base class for all unit tests."""
 
+    def __init__(self, *args, **kwargs):
+        super(TestCase, self).__init__(*args, **kwargs)
+
+        # This is the number of characters shown when two objects do not
+        # match for assertDictEqual, assertMultiLineEqual, and
+        # assertSequenceEqual. The default is 640 which is too
+        # low for comparing most dicts
+        self.maxDiff = 10000
+
     def setUp(self):
         super(TestCase, self).setUp()
         self.addCleanup(mock.patch.stopall)
         plugins.load()
+        self.useFixture(TempHomeDir())
 
     def _test_atomic_action_timer(self, atomic_actions, name, count=1,
                                   parent=[]):

tox.ini

@@ -74,6 +74,11 @@ commands =
 
 
 [testenv:cover]
+deps =
+  oslotest
+  -c {toxinidir}/upper-constraints.txt
+  -r{toxinidir}/requirements.txt
+  -r{toxinidir}/test-requirements.txt
 commands = {toxinidir}/tests/ci/cover.sh {posargs}