(maint) Remove phatom VMs and ensure inventory is successful

Previously, if inventory failed for some reason, it would return an incomplete
set of VMs which could then cause the pool to perform off behaviours such as
fill the pool high than it should, or remove VMs which exist.  Also, if the
redis cache of VMs in a pool had a VM but it did not actually exist in the
inventory it would never be removed.

This commit:
- Immediately exits the check_pool if an error occurs during inventory
  collection
- Will mark a VM as completed if it exists in Redis, but does not exist in
  inventory
- Adds tests for these behaviours

spec/unit/pool_manager_spec.rb

@@ -2347,12 +2347,13 @@ EOT
   task_limit: 10
 :pools:
   - name: #{pool}
-    size: 0
+    size: 10
 EOT
       )
     }
     let(:pool_object) { config[:pools][0] }
     let(:new_vm) { 'newvm'}
+    let(:pool_name) { pool_object['name'] }
 
     before do
       expect(subject).not_to be_nil
@@ -2378,6 +2379,46 @@ EOT
         subject._check_pool(pool_object,provider)
       end
 
+      it 'should not perform any other actions if an error occurs' do
+        # Add VMs into redis
+        create_running_vm(pool_name, 'vm1')
+        create_ready_vm(pool_name, 'vm2')
+        create_completed_vm('vm3', pool_name)
+        create_discovered_vm('vm4', pool_name)
+        create_migrating_vm('vm5', pool_name)
+
+        expect(subject).to receive(:move_vm_queue).exactly(0).times
+        expect(subject).to receive(:check_running_vm).exactly(0).times
+        expect(subject).to receive(:check_pending_vm).exactly(0).times
+        expect(subject).to receive(:destroy_vm).exactly(0).times
+        expect(redis).to receive(:srem).exactly(0).times
+        expect(redis).to receive(:del).exactly(0).times
+        expect(redis).to receive(:hdel).exactly(0).times
+        expect(redis).to receive(:smove).exactly(0).times
+        expect(subject).to receive(:migrate_vm).exactly(0).times
+        expect(redis).to receive(:set).exactly(0).times
+        expect(redis).to receive(:incr).exactly(0).times
+        expect(subject).to receive(:clone_vm).exactly(0).times
+        expect(redis).to receive(:decr).exactly(0).times
+
+        expect(provider).to receive(:vms_in_pool).and_raise(RuntimeError,'Mock Error')
+        subject._check_pool(pool_object,provider)
+      end
+
+      it 'should return that no actions were taken' do
+        expect(provider).to receive(:vms_in_pool).and_raise(RuntimeError,'Mock Error')
+
+        result = subject._check_pool(pool_object,provider)
+
+        expect(result[:discovered_vms]).to be(0)
+        expect(result[:checked_running_vms]).to be(0)
+        expect(result[:checked_ready_vms]).to be(0)
+        expect(result[:checked_pending_vms]).to be(0)
+        expect(result[:destroyed_vms]).to be(0)
+        expect(result[:migrated_vms]).to be(0)
+        expect(result[:cloned_vms]).to be(0)
+      end
+
       it 'should log the discovery of VMs' do
         expect(logger).to receive(:log).with('s', "[?] [#{pool}] '#{new_vm}' added to 'discovered' queue")
 
@@ -2428,11 +2469,17 @@ EOT
         create_running_vm(pool,vm,token)
       end
 
-      it 'should not do anything' do
+      it 'should not call check_running_vm' do
         expect(subject).to receive(:check_running_vm).exactly(0).times
 
         subject._check_pool(pool_object,provider)
       end
+
+      it 'should move the VM to completed queue' do
+        expect(subject).to receive(:move_vm_queue).with(pool,vm,'running','completed',String).and_call_original
+
+        subject._check_pool(pool_object,provider)
+      end
     end
 
     context 'Running VM in the inventory' do
@@ -2487,11 +2534,17 @@ EOT
         create_ready_vm(pool,vm,token)
       end
 
-      it 'should not do anything' do
+      it 'should not call check_ready_vm' do
         expect(subject).to receive(:check_ready_vm).exactly(0).times
 
         subject._check_pool(pool_object,provider)
       end
+
+      it 'should move the VM to completed queue' do
+        expect(subject).to receive(:move_vm_queue).with(pool,vm,'ready','completed',String).and_call_original
+
+        subject._check_pool(pool_object,provider)
+      end
     end
 
     context 'Ready VM in the inventory' do
@@ -2770,6 +2823,17 @@ EOT
 
     # REPOPULATE
     context 'Repopulate a pool' do
+    let(:config) {
+      YAML.load(<<-EOT
+---
+:config:
+  task_limit: 10
+:pools:
+  - name: #{pool}
+    size: 0
+EOT
+      )
+    }
       it 'should not call clone_vm when number of VMs is equal to the pool size' do
         expect(provider).to receive(:vms_in_pool).with(pool).and_return([])
         expect(subject).to receive(:clone_vm).exactly(0).times
@@ -2817,18 +2881,24 @@ EOT
       end
 
       context 'when pool is marked as empty' do
+        let(:vm_response) {
+          # Mock response from Base Provider for vms_in_pool
+          [{ 'name' => vm}]
+        }          
+
         before(:each) do
-        expect(provider).to receive(:vms_in_pool).with(pool).and_return([])
           redis.set("vmpooler__empty__#{pool}", 'true')
         end
 
         it 'should not log a message when the pool remains empty' do
+          expect(provider).to receive(:vms_in_pool).with(pool).and_return([])
           expect(logger).to receive(:log).with('s', "[!] [#{pool}] is empty").exactly(0).times
 
           subject._check_pool(pool_object,provider)
         end
 
         it 'should remove the empty pool mark if it is no longer empty' do
+          expect(provider).to receive(:vms_in_pool).with(pool).and_return(vm_response)
           create_ready_vm(pool,vm,token)
 
           expect(redis.get("vmpooler__empty__#{pool}")).to be_truthy