Add CustomAttribute#name validation

Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1558618

app/models/custom_attribute.rb

@@ -4,6 +4,8 @@ class CustomAttribute < ApplicationRecord
  belongs_to :resource, :polymorphic => true
  serialize :serialized_value
 
+ validates :name, :format => {:with => /\A[\p{Alpha}_][\p{Alpha}_\d\$]*\z/, :message => "must begin with a letter (a-z, but also letters with diacritical marks and non-Latin letters) or an underscore (_). Subsequent characters can be letters, underscores, digits (0-9), or dollar signs ($)"}
+
  def value=(value)
  self.serialized_value = value
  self[:value] = value

spec/models/custom_attribute_spec.rb

@@ -17,4 +17,20 @@
  expected = RUBY_VERSION >= "2.4.0" ? :integer : :fixnum
  expect(int_custom_attribute.value_type).to eq(expected)
  end
+
+ context "must have a valid name" do
+ let(:invalid_everywhere) { [":", " ", "-"] }
+ let(:valid_everywhere) { ["a", "_", "á"] }
+ let(:valid_subsequent) { ["1", "$"] }
+
+ it "has a valid starting character" do
+ valid_everywhere.each { |char| expect(CustomAttribute.new(:name => "#{char}zzzzz")).to be_valid }
+ (invalid_everywhere + valid_subsequent).each { |char| expect(CustomAttribute.new(:name => "#{char}zzzzz")).not_to be_valid }
+ end
+
+ it "has a valid subsequent characters" do
+ (valid_everywhere + valid_subsequent).each { |char| expect(CustomAttribute.new(:name => "a#{char}")).to be_valid }
+ invalid_everywhere.each { |char| expect(CustomAttribute.new(:name => "a#{char}")).not_to be_valid }
+ end
+ end
 end