Add code to check number of available nodes for deployment

Change-Id: I58fbf17d3bb1c0661181aa03d7a0431cf976137f
Related-Bug: 1547381

fuelweb_test/helpers/checkers.py

@@ -47,6 +47,33 @@ from fuelweb_test.settings import PUBLIC_TEST_IP
 ssh_manager = SSHManager()
 
 
+@logwrap
+def validate_amount_nodes(
+        nodes, expected_amount,
+        state='discover', online=True):
+    """Validate amount of nodes in state
+
+    :type nodes: iterable
+    :type expected_amount: int
+    :type state: str
+    :type online: bool
+    :raises: Exception
+    """
+    fnodes = [
+        node for node in nodes
+        if node['online'] == online and node['status'] == state]
+    if len(fnodes) != expected_amount:
+        raise Exception(
+            'Nodes in state {state} (online: {online}): '
+            '{amount}, while expected: {expected}'.format(
+                state=state,
+                online=online,
+                amount=len(fnodes),
+                expected=expected_amount
+            )
+        )
+
+
 @logwrap
 def check_cinder_status(ip):
     """Parse output and return False if any enabled service is down.

fuelweb_test/models/environment.py

@@ -30,6 +30,7 @@ from core.models.collector_client import CollectorClient
 from core.helpers.log_helpers import logwrap
 from core.helpers.log_helpers import QuietLogger
 
+from fuelweb_test.helpers import checkers
 from fuelweb_test.helpers.decorators import revert_info
 from fuelweb_test.helpers.decorators import update_rpm_packages
 from fuelweb_test.helpers.decorators import upload_manifests
@@ -124,6 +125,12 @@ class EnvironmentModel(six.with_metaclass(SingletonMeta, object)):
 
         if not skip_timesync:
             self.sync_time()
+
+        checkers.validate_amount_nodes(
+            nodes=self.fuel_web.client.list_nodes(),
+            expected_amount=len(devops_nodes)
+        )
+
         return self.nailgun_nodes(devops_nodes)
 
     def sync_time(self, nodes_names=None, skip_sync=False):