Allow model settings to be added or overridden

doc/source/runningcharmtests.rst

@@ -19,6 +19,21 @@ application versions, topologies or config options.  functest-run-suite will
 run through each phase listed below in order for each bundle that is to be
 tested.
 
+0) Environment Variables
+~~~~~~~~~~~~~~~~~~~~~~~~
+
+Optionally setting the **MODEL_SETTINGS** environment variable allows model
+settings to be applied to the models created by zaza to run tests in. The
+settings will be applied on top of those set 
+**charm_lifecycle.prepare.MODEL_DEFAULTS** so it can be used to override any
+default setting.
+
+**MODEL_SETTINGS** should be a list of key/value pairs delimited by
+semicolon e.g.::
+
+    export MODEL_SETTINGS="virt-type=kvm;no-proxy=jujucharms.com"
+
+
 1) Prepare
 ~~~~~~~~~~
 

unit_tests/test_zaza_charm_lifecycle_prepare.py

@@ -1,11 +1,62 @@
+import copy
+import mock
+
 import zaza.charm_lifecycle.prepare as lc_prepare
 import unit_tests.utils as ut_utils
 
 
 class TestCharmLifecyclePrepare(ut_utils.BaseTestCase):
 
+    MODEL_CONFIG_DEFAULTS = lc_prepare.MODEL_DEFAULTS
+
+    def base_get_model_settings(self, env, expect):
+        with mock.patch.dict(lc_prepare.os.environ, env):
+            self.assertEqual(lc_prepare.get_model_settings(), expect)
+
+    def test_get_model_settings_no_config(self):
+        expect_config = copy.deepcopy(self.MODEL_CONFIG_DEFAULTS)
+        self.base_get_model_settings({}, expect_config)
+
+    def test_get_model_settings_empty_config(self):
+        expect_config = copy.deepcopy(self.MODEL_CONFIG_DEFAULTS)
+        self.base_get_model_settings({'MODEL_SETTINGS': ''}, expect_config)
+
+    def test_get_model_settings_single_value(self):
+        expect_config = copy.deepcopy(self.MODEL_CONFIG_DEFAULTS)
+        expect_config.update({'virt-type': 'kvm'})
+        self.base_get_model_settings(
+            {'MODEL_SETTINGS': 'virt-type=kvm'},
+            expect_config)
+
+    def test_get_model_settings_multiple_values(self):
+        expect_config = copy.deepcopy(self.MODEL_CONFIG_DEFAULTS)
+        expect_config.update({
+            'virt-type': 'kvm',
+            'no-proxy': 'jujucharms.com'})
+        self.base_get_model_settings(
+            {'MODEL_SETTINGS': 'virt-type=kvm;no-proxy=jujucharms.com'},
+            expect_config)
+
+    def test_get_model_settings_multiple_values_override(self):
+        expect_config = copy.deepcopy(self.MODEL_CONFIG_DEFAULTS)
+        expect_config.update({'test-mode': 'false'})
+        self.base_get_model_settings(
+            {'MODEL_SETTINGS': 'test-mode=false'},
+            expect_config)
+
+    def test_get_model_settings_whitespace(self):
+        expect_config = copy.deepcopy(self.MODEL_CONFIG_DEFAULTS)
+        expect_config.update({
+            'test-mode': 'false',
+            'virt-type': 'kvm'})
+        self.base_get_model_settings(
+            {'MODEL_SETTINGS': ' test-mode= false ; virt-type=  kvm'},
+            expect_config)
+
     def test_prepare(self):
         self.patch_object(lc_prepare.zaza.controller, 'add_model')
+        self.patch_object(lc_prepare, 'get_model_settings')
+        self.get_model_settings.return_value = lc_prepare.MODEL_DEFAULTS
         lc_prepare.prepare('newmodel')
         self.add_model.assert_called_once_with(
             'newmodel',

zaza/charm_lifecycle/prepare.py

@@ -1,6 +1,8 @@
 """Run prepare phase."""
 import argparse
+import copy
 import logging
+import os
 import sys
 
 import zaza.controller
@@ -21,13 +23,28 @@ MODEL_DEFAULTS = {
 }
 
 
+def get_model_settings():
+    """Construct settings for model from defaults and env variables.
+
+    :returns: Settings to usee for model
+    :rtype: Dict
+    """
+    model_settings = copy.deepcopy(MODEL_DEFAULTS)
+    for setting in os.environ.get('MODEL_SETTINGS', '').split(';'):
+        if not setting:
+            continue
+        key, value = setting.split('=')
+        model_settings[key.strip()] = value.strip()
+    return model_settings
+
+
 def prepare(model_name):
     """Run all steps to prepare the environment before a functional test run.
 
     :param model: Name of model to add
     :type bundle: str
     """
-    zaza.controller.add_model(model_name, config=MODEL_DEFAULTS)
+    zaza.controller.add_model(model_name, config=get_model_settings())
 
 
 def parse_args(args):