Validate uniqueness of Contact#value

app/models/contact.rb

@@ -23,7 +23,9 @@ class Contact < ApplicationRecord
 
   validates :contact_network, presence: true
 
-  validates :value, presence: true
+  validates :value,
+            presence: true,
+            uniqueness: { scope: %i[contact_list_id contact_network_id] }
 
 private
 

db/migrate/20181129203927_initial_migration.rb

@@ -178,6 +178,10 @@ private
       t.references :contact_network, null: false, index: true, foreign_key: true
 
       t.string :value, null: false
+
+      t.index %i[contact_list_id contact_network_id value],
+              name: :index_contacts_on_list_id_and_network_id_and_value,
+              unique: true
     end
 
     create_table :federal_subjects do |t|

db/structure.sql

@@ -1156,6 +1156,13 @@ CREATE INDEX index_contacts_on_contact_list_id ON public.contacts USING btree (c
 CREATE INDEX index_contacts_on_contact_network_id ON public.contacts USING btree (contact_network_id);
 
 
+--
+-- Name: index_contacts_on_list_id_and_network_id_and_value; Type: INDEX; Schema: public; Owner: -
+--
+
+CREATE UNIQUE INDEX index_contacts_on_list_id_and_network_id_and_value ON public.contacts USING btree (contact_list_id, contact_network_id, value);
+
+
 --
 -- Name: index_federal_subjects_on_english_name; Type: INDEX; Schema: public; Owner: -
 --

spec/models/contact_spec.rb

@@ -24,6 +24,12 @@ RSpec.describe Contact do
 
     it { is_expected.to validate_presence_of :value }
 
+    it do
+      is_expected.to \
+        validate_uniqueness_of(:value)
+        .scoped_to(:contact_list_id, :contact_network_id)
+    end
+
     it { is_expected.not_to allow_value nil }
     it { is_expected.not_to allow_value '' }
     it { is_expected.not_to allow_value ' ' * rand(1..3) }