Add Relation#find_or_create_by and friends

This is similar to #first_or_create, but slightly different and a nicer
API. See the CHANGELOG/docs in the commit.

Fixes #7853

1 files changed, 23 insertions, 0 deletions

diff --git a/activerecord/test/cases/relations_test.rb b/activerecord/test/cases/relations_test.rb
index fdbc0a3fdb..7504da01d5 100644
--- a/activerecord/test/cases/relations_test.rb
+++ b/activerecord/test/cases/relations_test.rb
@@ -1058,6 +1058,29 @@ class RelationTest < ActiveRecord::TestCase
     assert_equal 'parrot', parrot.name
   end
 
+  def test_find_or_create_by
+    assert_nil Bird.find_by(name: 'bob')
+
+    bird = Bird.find_or_create_by(name: 'bob')
+    assert bird.persisted?
+
+    assert_equal bird, Bird.find_or_create_by(name: 'bob')
+  end
+
+  def test_find_or_create_by!
+    assert_raises(ActiveRecord::RecordInvalid) { Bird.find_or_create_by!(color: 'green') }
+  end
+
+  def test_find_or_initialize_by
+    assert_nil Bird.find_by(name: 'bob')
+
+    bird = Bird.find_or_initialize_by(name: 'bob')
+    assert bird.new_record?
+    bird.save!
+
+    assert_equal bird, Bird.find_or_initialize_by(name: 'bob')
+  end
+
   def test_explicit_create_scope
     hens = Bird.where(:name => 'hen')
     assert_equal 'hen', hens.new.name