Prevent unsupported classes from being added

app/models/ems_refresh/manager.rb

@@ -4,6 +4,8 @@ module Manager
     module ClassMethods
       unless respond_to?(:ems_type)
         def ems_type
+          ActiveSupport::Deprecation.warn("ems_type is required.", caller[1..-1])
+          #{}"vmwarews"
         end
       end
     end

app/models/ext_management_system.rb

@@ -40,6 +40,10 @@ def self.supported_for_create?
     !reflections.include?("parent_manager")
   end
 
+  def self.ems_type_supported_for_create?
+    ExtManagementSystem.supported_types_and_descriptions_hash.key?(ems_type)
+  end
+
   belongs_to :provider
   has_many :child_managers, :class_name => 'ExtManagementSystem', :foreign_key => 'parent_ems_id'
 
@@ -101,8 +105,8 @@ def self.supported_for_create?
   validates :name,     :presence => true, :uniqueness => {:scope => [:tenant_id]}
   validates :hostname, :presence => true, :if => :hostname_required?
   validate :hostname_uniqueness_valid?, :hostname_format_valid?, :if => :hostname_required?
-
   validate :validate_ems_enabled_when_zone_changed?, :validate_zone_not_maintenance_when_ems_enabled?
+  validate :validate_ems_type, :on => :create
 
   scope :with_eligible_manager_types, ->(eligible_types) { where(:type => Array(eligible_types).collect(&:to_s)) }
 
@@ -828,6 +832,10 @@ def allow_targeted_refresh?
 
   private
 
+  def validate_ems_type
+    errors.add :base, "emstype #{self.class.ems_type} is unsupported" unless self.class.ems_type_supported_for_create?
+  end
+
   def disable!
     _log.info("Disabling EMS [#{name}] id [#{id}].")
     update!(:enabled => false)

spec/models/ext_management_system_spec.rb

@@ -126,6 +126,16 @@
     expect(ems.total_storages).to eq 2
   end
 
+  context "supported_for_create?" do
+    it "base class is unsupported" do
+      expect { FactoryBot.create(:ext_management_system) }.to raise_error(ActiveRecord::RecordInvalid)
+    end
+
+    it "supported class is supported" do
+      expect(FactoryBot.create(:ems_vmware).class.supported_for_create?).to eq(true)
+    end
+  end
+
   context "#hostname / #hostname=" do
     it "will delegate to the default endpoint" do
       ems = FactoryBot.build(:ems_vmware, :hostname => "example.org")