Use custom EachValidators

Use custom EachValidator for project assosciation validation and
for Zoom URL validation.

app/models/zoom_meeting.rb

@@ -4,8 +4,8 @@ class ZoomMeeting < ApplicationRecord
   belongs_to :project, optional: false
   belongs_to :issue, optional: false
 
-  validates :url, presence: true, length: { maximum: 255 }
-  validates_with ZoomMeetingValidator
+  validates :url, presence: true, length: { maximum: 255 }, zoom_url: true
+  validates :issue, project_association: true
 
   enum issue_status: {
     added: 1,
@@ -14,5 +14,4 @@ class ZoomMeeting < ApplicationRecord
 
   scope :added_to_issue, -> { where(issue_status: :added) }
   scope :removed_from_issue, -> { where(issue_status: :removed) }
-
 end

app/validators/project_association_validator.rb

+# frozen_string_literal: true
+
+# IssueProjectAssociationValidator
+#
+# Custom validator to validate that the same project associated with
+# the record is also associated with the value
+#
+# Example:
+# class ZoomMeeting < ApplicationRecord
+#   belongs_to :project, optional: false
+#   belongs_to :issue, optional: false
+
+#   validates :issue, issue_project_association: true
+# end
+class ProjectAssociationValidator < ActiveModel::EachValidator
+  def validate_each(record, attribute, value)
+    return if record.project == value&.project
+
+    record.errors[attribute] << 'must associate the same project'
+  end
+end

app/validators/zoom_meeting_validator.rb

-# frozen_string_literal: true
-
-# ZoomMeetingValidator
-#
-# Custom validator to TODO
-#
-class ZoomMeetingValidator < ActiveModel::Validator
-  def validate(zoom_meeting)
-    unless Gitlab::ZoomLinkExtractor.new(zoom_meeting.url).links.size == 1
-      zoom_meeting.errors.add(:url, 'must contain one valid Zoom URL')
-    end
-    unless zoom_meeting.project == zoom_meeting.issue&.project
-      zoom_meeting.errors.add(:issue, 'must associate the same project')
-    end
-    true
-  end
-end

app/validators/zoom_url_validator.rb

+# frozen_string_literal: true
+
+# ZoomUrlValidator
+#
+# Custom validator for zoom urls
+#
+class ZoomUrlValidator < ActiveModel::EachValidator
+  def validate_each(record, attribute, value)
+    return if Gitlab::ZoomLinkExtractor.new(value).links.size == 1
+
+    record.errors.add(:url, 'must contain one valid Zoom URL')
+  end
+end