Modify api_fake_data's api_handler to be lazy

Previously api_handler function returned a lambda, that could be used as
a decorator and would return fake or real function, depending on a
global variable. The decision was made at import time. This made it very
difficult to test decorated functions behaviour, since these functions
were decorated away before there was any chance to mock config or global
variable.
With this commit api_handler returns a decorator, that, when applied,
returns a function, that proxies calls to fake or real api function,
depending on global variable.
This consequently means there will be an extra function call for every
request. However this would potentially allow us to switch behaviour
from/to fake functions on the fly.

This commit also restores fake decorators around health API functions.

ceagle/api/v1/status.py

@@ -32,6 +32,7 @@ def get_status(period):
 
 
 @bp_status.route("/health/<period>")
+@fake_status.get_status_health
 def get_status_health(period):
     health_client = client.get_client("health")
     if not health_client:
@@ -62,6 +63,7 @@ def get_region_status(region, period):
 
 
 @bp_region_status.route("/<region>/status/health/<period>")
+@fake_status.get_region_status_health
 def get_region_status_health(region, period):
     health_client = client.get_client("health")
     if not health_client:

ceagle/api_fake_data/base.py

@@ -13,6 +13,7 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+import functools
 import random
 
 from ceagle import config
@@ -23,7 +24,22 @@
 
 
 def api_handler(fake):
-    return lambda real: USE_FAKE_DATA and fake or real
+    """Function that handles api_fake_data substitution functions
+
+    It is intended to be used as a decorator around fake api functions. It
+    turns a function it decorates into a decorator, that accepts "real" api
+    function (real_function_handler). The resulting decorator returns a
+    (choice_maker) function, that calls real or fake function, depending on the
+    value of USE_FAKE_DATA global variable.
+    """
+    def real_function_handler(real):
+        @functools.wraps(real)
+        def choice_maker(*args, **kwargs):
+            if USE_FAKE_DATA:
+                return fake(*args, **kwargs)
+            return real(*args, **kwargs)
+        return choice_maker
+    return real_function_handler
 
 
 def randnum(from_num, to_num, round_by=2):

tests/unit/api/v1/test_status.py

@@ -15,6 +15,7 @@
 
 import mock
 
+from ceagle.api_fake_data import base as fake_api_base
 from tests.unit import test
 
 
@@ -23,9 +24,11 @@ class ApiTestCase(test.TestCase):
     def test_api_response_code(self):
         region = "north-2.piedpiper.net"
         for urlpath in ("/api/v1/status",
+                        "/api/v1/status/health",
                         "/api/v1/status/performance",
                         "/api/v1/status/availability",
                         "/api/v1/region/%s/status" % region,
+                        "/api/v1/region/%s/status/health" % region,
                         "/api/v1/region/%s/status/performance" % region,
                         "/api/v1/region/%s/status/availability" % region):
             for suffix, code in (
@@ -45,17 +48,26 @@ class HealthApiTestCase(test.TestCase):
 
     def setUp(self):
         super(HealthApiTestCase, self).setUp()
-        self.health_config = {"health": {
-            "endpoint": "http://dummy.example.org/api/health"
-        }}
+        self.health_config = {
+            "services": {
+                "health": "http://dummy.example.org/api/health"
+            }
+        }
+
+        self.old_USE_FAKE_DATA = fake_api_base.USE_FAKE_DATA
+        fake_api_base.USE_FAKE_DATA = False
+
+    def tearDown(self):
+        fake_api_base.USE_FAKE_DATA = self.old_USE_FAKE_DATA
+        super(HealthApiTestCase, self).tearDown()
 
     @mock.patch("ceagle.api.client.Client")
     def test_status_health_api(self, mock_client, mock_get_config):
         mock_get_config.return_value = self.health_config
         mock_client.return_value.get.return_value = {"status_code": 200}
         code, resp = self.get("/api/v1/status/health/day")
-        mock_client.return_value.get.assert_called_with(
-            "/api/v1/health", params={"period": u"day"})
+
+        mock_client.return_value.get.assert_called_with("/api/v1/health/day")
         self.assertEqual(200, code)
 
     @mock.patch("ceagle.api.client.Client")
@@ -65,7 +77,7 @@ def test_region_status_health_api(self, mock_client, mock_get_config):
 
         code, resp = self.get("/api/v1/region/test_region/status/health/day")
         mock_client.return_value.get.assert_called_with(
-            "/api/v1/health/test_region", params={"period": u"day"})
+            "/api/v1/region/test_region/health/day")
         self.assertEqual(200, code)
 
     def test_health_api_no_endpoint(self, mock_get_config):

tests/unit/api_fake_data/test_base.py

@@ -24,10 +24,12 @@ class ModuleTestCase(test.TestCase):
     @mock.patch("ceagle.api_fake_data.base.config")
     def test_api_handler(self, mock_config):
         mock_config.get_config.return_value = {}
-        self.assertEqual("fake", base.api_handler("fake")("real"))
+        fake = lambda: "fake"
+        real = lambda: "real"
+        self.assertEqual("fake", base.api_handler(fake)(real)())
         self.assertEqual(base.USE_FAKE_DATA, True)
         base.USE_FAKE_DATA = False
-        self.assertEqual("real", base.api_handler("fake")("real"))
+        self.assertEqual("real", base.api_handler(fake)(real)())
 
     @mock.patch("ceagle.api_fake_data.base.random")
     def test_randnum(self, mock_random):