Fail with descriptive message when no EMS

app/models/miq_provision_request.rb

@@ -26,13 +26,24 @@ class MiqProvisionRequest < MiqRequest
 
   def self.request_task_class_from(attribs)
     source_id = MiqRequestMixin.get_option(:src_vm_id, nil, attribs['options'])
-    vm_or_template = VmOrTemplate.find_by(:id => source_id)
-    raise MiqException::MiqProvisionError, "Unable to find source Template/Vm with id [#{source_id}]" if vm_or_template.nil?
+    vm_or_template = source_vm_or_template!(source_id)
 
     via = MiqRequestMixin.get_option(:provision_type, nil, attribs['options'])
     vm_or_template.ext_management_system.class.provision_class(via)
   end
 
+  def self.source_vm_or_template!(source_id)
+    vm_or_template = VmOrTemplate.find_by(:id => source_id)
+    if vm_or_template.nil?
+      raise MiqException::MiqProvisionError, "Unable to find source Template/Vm with id [#{source_id}]"
+    end
+
+    if vm_or_template.ext_management_system.nil?
+      raise MiqException::MiqProvisionError, "Source Template/Vm with id [#{source_id}] has no EMS, unable to provision"
+    end
+    vm_or_template
+  end
+
   def self.new_request_task(attribs)
     klass = request_task_class_from(attribs)
     klass.new(attribs)

spec/models/miq_provision_request_spec.rb

@@ -1,21 +1,32 @@
 describe MiqProvisionRequest do
-  it ".request_task_class_from" do
-    ems = FactoryGirl.create(:ems_vmware)
-    vm = FactoryGirl.create(:vm_vmware, :ext_management_system => ems)
-    expect(described_class.request_task_class_from('options' => {:src_vm_id => vm.id})).to eq ManageIQ::Providers::Vmware::InfraManager::Provision
-    expect(described_class.request_task_class_from('options' => {:src_vm_id => vm.id, :provision_type => "pxe"})).to eq ManageIQ::Providers::Vmware::InfraManager::ProvisionViaPxe
-
-    ems = FactoryGirl.create(:ems_redhat)
-    vm = FactoryGirl.create(:vm_redhat, :ext_management_system => ems)
-    expect(described_class.request_task_class_from('options' => {:src_vm_id => vm.id})).to eq ManageIQ::Providers::Redhat::InfraManager::Provision
-
-    ems = FactoryGirl.create(:ems_openstack)
-    vm = FactoryGirl.create(:vm_openstack, :ext_management_system => ems)
-    expect(described_class.request_task_class_from('options' => {:src_vm_id => vm.id})).to eq ManageIQ::Providers::Openstack::CloudManager::Provision
-
-    ems = FactoryGirl.create(:ems_amazon)
-    vm = FactoryGirl.create(:vm_amazon, :ext_management_system => ems)
-    expect(described_class.request_task_class_from('options' => {:src_vm_id => vm.id})).to eq ManageIQ::Providers::Amazon::CloudManager::Provision
+  context "#request_task_class_from" do
+    it "retrieves the provision class when the vm has EMS" do
+      ems = FactoryGirl.create(:ems_vmware)
+      vm = FactoryGirl.create(:vm_vmware, :ext_management_system => ems)
+      expect(described_class.request_task_class_from('options' => {:src_vm_id => vm.id})).to eq ManageIQ::Providers::Vmware::InfraManager::Provision
+      expect(described_class.request_task_class_from('options' => {:src_vm_id => vm.id, :provision_type => "pxe"})).to eq ManageIQ::Providers::Vmware::InfraManager::ProvisionViaPxe
+
+      ems = FactoryGirl.create(:ems_redhat)
+      vm = FactoryGirl.create(:vm_redhat, :ext_management_system => ems)
+      expect(described_class.request_task_class_from('options' => {:src_vm_id => vm.id})).to eq ManageIQ::Providers::Redhat::InfraManager::Provision
+
+      ems = FactoryGirl.create(:ems_openstack)
+      vm = FactoryGirl.create(:vm_openstack, :ext_management_system => ems)
+      expect(described_class.request_task_class_from('options' => {:src_vm_id => vm.id})).to eq ManageIQ::Providers::Openstack::CloudManager::Provision
+
+      ems = FactoryGirl.create(:ems_amazon)
+      vm = FactoryGirl.create(:vm_amazon, :ext_management_system => ems)
+      expect(described_class.request_task_class_from('options' => {:src_vm_id => vm.id})).to eq ManageIQ::Providers::Amazon::CloudManager::Provision
+    end
+
+    it "fails to retrieve the provision class when the vm has no EMS" do
+      vm = FactoryGirl.create(:vm_redhat)
+      expect { described_class.request_task_class_from('options' => {:src_vm_id => vm.id}) }.to raise_error(MiqException::MiqProvisionError)
+    end
+
+    it "fails to retrieve the provision class when the vm does not exist" do
+      expect { described_class.request_task_class_from('options' => {:src_vm_id => -1 }) }.to raise_error(MiqException::MiqProvisionError)
+    end
   end
 
   context "A new provision request," do