diff --git a/tempest/api/network/base.py b/tempest/api/network/base.py
index e0e40cb..8068284 100644
--- a/tempest/api/network/base.py
+++ b/tempest/api/network/base.py
@@ -73,6 +73,7 @@
         cidr = netaddr.IPNetwork(cls.network_cfg.tenant_network_cidr)
         mask_bits = cls.network_cfg.tenant_network_mask_bits
         # Find a cidr that is not in use yet and create a subnet with it
+        failure = None
         for subnet_cidr in cidr.subnet(mask_bits):
             try:
                 resp, body = cls.client.create_subnet(network['id'],
@@ -82,6 +83,12 @@
                 is_overlapping_cidr = 'overlaps with another subnet' in str(e)
                 if not is_overlapping_cidr:
                     raise
+                # save the failure in case all of the CIDRs are overlapping
+                failure = e
+
+        if not body and failure:
+            raise failure
+
         subnet = body['subnet']
         cls.subnets.append(subnet)
         return subnet
diff --git a/tempest/whitebox/test_servers_whitebox.py b/tempest/whitebox/test_servers_whitebox.py
index cd3c026..2694b95 100644
--- a/tempest/whitebox/test_servers_whitebox.py
+++ b/tempest/whitebox/test_servers_whitebox.py
@@ -50,70 +50,6 @@
             except exceptions.NotFound:
                 continue
 
-    def test_create_server_vcpu_quota_full(self):
-        # Disallow server creation when tenant's vcpu quota is full
-        quotas = self.meta.tables['quotas']
-        stmt = (quotas.select().
-                where(quotas.c.project_id == self.tenant_id).
-                where(quotas.c.resource == 'cores'))
-        result = self.connection.execute(stmt).first()
-
-        # Set vcpu quota for tenant if not already set
-        if not result:
-            cores_hard_limit = 2
-            stmt = quotas.insert().values(deleted=0,
-                                          project_id=self.tenant_id,
-                                          resource='cores',
-                                          hard_limit=cores_hard_limit)
-
-            self.connection.execute(stmt, autocommit=True)
-        else:
-            cores_hard_limit = result.hard_limit
-
-        # Create servers assuming 1 VCPU per instance i.e flavor_id=1
-        try:
-            for count in range(cores_hard_limit + 1):
-                self.create_server()
-        except exceptions.OverLimit:
-            pass
-        else:
-            self.fail("Could create servers over the VCPU quota limit")
-        finally:
-            stmt = quotas.delete()
-            self.connection.execute(stmt, autocommit=True)
-
-    def test_create_server_memory_quota_full(self):
-        # Disallow server creation when tenant's memory quota is full
-        quotas = self.meta.tables['quotas']
-        stmt = (quotas.select().
-                where(quotas.c.project_id == self.tenant_id).
-                where(quotas.c.resource == 'ram'))
-        result = self.connection.execute(stmt).first()
-
-        # Set memory quota for tenant if not already set
-        if not result:
-            ram_hard_limit = 1024
-            stmt = quotas.insert().values(deleted=0,
-                                          project_id=self.tenant_id,
-                                          resource='ram',
-                                          hard_limit=ram_hard_limit)
-
-            self.connection.execute(stmt, autocommit=True)
-        else:
-            ram_hard_limit = result.hard_limit
-
-        try:
-            # Set a hard range of 3 servers for reaching the RAM quota
-            for count in range(3):
-                self.create_server()
-        except exceptions.OverLimit:
-            pass
-        else:
-            self.fail("Could create servers over the RAM quota limit")
-        finally:
-            stmt = quotas.delete()
-            self.connection.execute(stmt, autocommit=True)
-
     def update_state(self, server_id, vm_state, task_state, deleted=0):
         """Update states of an instance in database for validation."""
         if not task_state: