[Plugins] Class-based scenario DummyFailure

This adds the first class-based scenario.

Change-Id: Ia1a0ea6988b21f792070ac15e425dc52441ff4c2
Implements: class-based-scenarios

rally-jobs/rally.yaml

@@ -672,6 +672,26 @@
           action_3: 4.0
           action_4: 5.0
 
+  dummy.failure:
+    -
+      args:
+        sleep: 0.2
+        from_iteration: 5
+        to_iteration: 15
+        each: 2
+      runner:
+        type: "constant"
+        times: 20
+        concurrency: 5
+      context:
+        users:
+          tenants: 1
+          users_per_tenant: 1
+      sla:
+        failure_rate:
+          min: 25
+          max: 25
+
   FakePlugin.testplugin:
     -
       runner:

rally/plugins/common/scenarios/dummy/dummy.py

@@ -28,6 +28,28 @@ class DummyScenarioException(exceptions.RallyException):
     msg_fmt = _("Dummy scenario expected exception: '%(message)s'")
 
 
+@scenario.configure(name="dummy.failure")
+class DummyFailure(scenario.Scenario):
+    """Dummy benchmarks for testing Rally benchmark engine at scale."""
+
+    def run(self, sleep=0.1, from_iteration=0, to_iteration=0, each=1):
+        """Raise errors in some iterations.
+
+        :param sleep: float iteration sleep time in seconds
+        :param from_iteration: int iteration number which starts range
+                             of failed iterations
+        :param to_iteration: int iteration number which ends range of
+                             failed iterations
+        :param each: int cyclic number of iteration which actually raises
+                     an error in selected range. For example, each=3 will
+                     raise error in each 3rd iteration.
+        """
+        utils.interruptable_sleep(sleep)
+        if from_iteration <= self.context["iteration"] <= to_iteration:
+            if each and not self.context["iteration"] % each:
+                raise DummyScenarioException(_("Expected failure"))
+
+
 class Dummy(scenario.Scenario):
     """Dummy benchmarks for testing Rally benchmark engine at scale."""
 

samples/tasks/scenarios/dummy/dummy-failure.json

@@ -0,0 +1,23 @@
+{
+    "dummy.failure": [
+        {
+            "args": {
+                "sleep": 0.2,
+                "from_iteration": 5,
+                "to_iteration": 10,
+                "each": 2
+            },
+            "runner": {
+                "type": "constant",
+                "times": 20,
+                "concurrency": 5
+            },
+            "context": {
+                "users": {
+                    "tenants": 1,
+                    "users_per_tenant": 1
+                }
+            }
+        }
+    ]
+}

samples/tasks/scenarios/dummy/dummy-failure.yaml

@@ -0,0 +1,16 @@
+---
+  dummy.failure:
+    -
+      args:
+        sleep: 0.2
+        from_iteration: 5
+        to_iteration: 10
+        each: 2
+      runner:
+        type: "constant"
+        times: 20
+        concurrency: 5
+      context:
+        users:
+          tenants: 1
+          users_per_tenant: 1

tests/unit/plugins/common/scenarios/dummy/test_dummy.py

@@ -21,6 +21,44 @@ from tests.unit import test
 DUMMY = "rally.plugins.common.scenarios.dummy.dummy."
 
 
+@ddt.ddt
+class DummyFailureTestCase(test.TestCase):
+
+    @ddt.data({"iteration": 0, "kwargs": {}},
+              {"iteration": 0, "kwargs": {"each": 1}},
+              {"iteration": 5, "kwargs": {"from_iteration": 4},
+               "raises": False},
+              {"iteration": 5,
+               "kwargs": {"from_iteration": 5, "to_iteration": 5}},
+              {"iteration": 5,
+               "kwargs": {"from_iteration": 4, "to_iteration": 5}},
+              {"iteration": 5,
+               "kwargs": {"from_iteration": 5, "to_iteration": 6}},
+              {"iteration": 5,
+               "kwargs": {"from_iteration": 4, "to_iteration": 6}},
+              {"iteration": 5, "kwargs": {"from_iteration": 4,
+                                          "to_iteration": 6, "sleep": 5}},
+              {"iteration": 5, "raises": False,
+               "kwargs": {"from_iteration": 4, "to_iteration": 6,
+                          "sleep": 5, "each": 2}},
+              {"iteration": 6, "kwargs": {"from_iteration": 4,
+                                          "to_iteration": 6,
+                                          "sleep": 5, "each": 2}})
+    @ddt.unpack
+    @mock.patch(DUMMY + "utils.interruptable_sleep")
+    def test_run(self, mock_interruptable_sleep, iteration, kwargs,
+                 raises=True):
+        scenario = dummy.DummyFailure(
+            test.get_test_context(iteration=iteration))
+        if raises:
+            self.assertRaises(dummy.DummyScenarioException, scenario.run,
+                              **kwargs)
+        else:
+            scenario.run(**kwargs)
+        mock_interruptable_sleep.assert_called_once_with(
+            kwargs.get("sleep", 0.1))
+
+
 @ddt.ddt
 class DummyTestCase(test.TestCase):