Avoid a string value truncation in uniqueness validation

In MySQL, PostgreSQL, Oracle and SQLServer, a value over the limit
cannot be inserted or updated (See #23522).

In SQLite3, a value is inserted or updated regardless of the limit.

We should avoid a string value truncation in uniqueness validation.

1 files changed, 22 insertions, 10 deletions

diff --git a/activerecord/test/cases/validations/uniqueness_validation_test.rb b/activerecord/test/cases/validations/uniqueness_validation_test.rb
index e601c53dbf..6264ec15d0 100644
--- a/activerecord/test/cases/validations/uniqueness_validation_test.rb
+++ b/activerecord/test/cases/validations/uniqueness_validation_test.rb
@@ -336,19 +336,31 @@ class UniquenessValidationTest < ActiveRecord::TestCase
   end
 
   def test_validate_uniqueness_with_limit
-    # Event.title is limited to 5 characters
-    e1 = Event.create(:title => "abcde")
-    assert e1.valid?, "Could not create an event with a unique, 5 character title"
-    e2 = Event.create(:title => "abcdefgh")
-    assert !e2.valid?, "Created an event whose title, with limit taken into account, is not unique"
+    if current_adapter?(:SQLite3Adapter)
+      # Event.title has limit 5, but does not affected in SQLite.
+      e1 = Event.create(title: "abcdefgh")
+      assert e1.valid?, "Could not create an event with a unique 8 characters title"
+      e2 = Event.create(title: "abcdefgh")
+      assert !e2.valid?, "Created an event whose title is not unique"
+    elsif current_adapter?(:Mysql2Adapter, :PostgreSQLAdapter, :OracleAdapter, :SQLServerAdapter)
+      assert_raise(ActiveRecord::StatementInvalid) do
+        Event.create(title: "abcdefgh")
+      end
+    end
   end
 
   def test_validate_uniqueness_with_limit_and_utf8
-    # Event.title is limited to 5 characters
-    e1 = Event.create(:title => "一二三四五")
-    assert e1.valid?, "Could not create an event with a unique, 5 character title"
-    e2 = Event.create(:title => "一二三四五六七八")
-    assert !e2.valid?, "Created an event whose title, with limit taken into account, is not unique"
+    if current_adapter?(:SQLite3Adapter)
+      # Event.title has limit 5, but does not affected in SQLite.
+      e1 = Event.create(title: "一二三四五六七八")
+      assert e1.valid?, "Could not create an event with a unique 8 characters title"
+      e2 = Event.create(title: "一二三四五六七八")
+      assert !e2.valid?, "Created an event whose title is not unique"
+    elsif current_adapter?(:Mysql2Adapter, :PostgreSQLAdapter, :OracleAdapter, :SQLServerAdapter)
+      assert_raise(ActiveRecord::StatementInvalid) do
+        Event.create(title: "一二三四五六七八")
+      end
+    end
   end
 
   def test_validate_straight_inheritance_uniqueness