1 files changed, 26 insertions, 5 deletions
diff --git a/activemodel/test/cases/errors_test.rb b/activemodel/test/cases/errors_test.rb
index 43aee5a814..fe351f922d 100644
--- a/activemodel/test/cases/errors_test.rb
+++ b/activemodel/test/cases/errors_test.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "cases/helper"
 require "active_support/core_ext/string/strip"
 require "yaml"
@@ -81,7 +83,7 @@ class ErrorsTest < ActiveModel::TestCase
 
     assert_equal 1, person.errors.count
     person.errors.clear
-    assert person.errors.empty?
+    assert_empty person.errors
   end
 
   test "error access is indifferent" do
@@ -126,8 +128,8 @@ class ErrorsTest < ActiveModel::TestCase
   test "detecting whether there are errors with empty?, blank?, include?" do
     person = Person.new
     person.errors[:foo]
-    assert person.errors.empty?
-    assert person.errors.blank?
+    assert_empty person.errors
+    assert_predicate person.errors, :blank?
     assert_not_includes person.errors, :foo
   end
 
@@ -221,6 +223,13 @@ class ErrorsTest < ActiveModel::TestCase
     assert !person.errors.added?(:name)
   end
 
+  test "added? returns false when checking for an error by symbol and a different error with same message is present" do
+    I18n.backend.store_translations("en", errors: { attributes: { name: { wrong: "is wrong", used: "is wrong" } } })
+    person = Person.new
+    person.errors.add(:name, :wrong)
+    assert !person.errors.added?(:name, :used)
+  end
+
   test "size calculates the number of error messages" do
     person = Person.new
     person.errors.add(:name, "cannot be blank")
@@ -311,7 +320,7 @@ class ErrorsTest < ActiveModel::TestCase
 
   test "generate_message works without i18n_scope" do
     person = Person.new
-    assert !Person.respond_to?(:i18n_scope)
+    assert_not_respond_to Person, :i18n_scope
     assert_nothing_raised {
       person.errors.generate_message(:name, :blank)
     }
@@ -362,7 +371,7 @@ class ErrorsTest < ActiveModel::TestCase
 
     assert_equal 1, person.errors.details.count
     person.errors.clear
-    assert person.errors.details.empty?
+    assert_empty person.errors.details
   end
 
   test "copy errors" do
@@ -375,6 +384,18 @@ class ErrorsTest < ActiveModel::TestCase
     assert_equal [:name], person.errors.details.keys
   end
 
+  test "merge errors" do
+    errors = ActiveModel::Errors.new(Person.new)
+    errors.add(:name, :invalid)
+
+    person = Person.new
+    person.errors.add(:name, :blank)
+    person.errors.merge!(errors)
+
+    assert_equal({ name: ["can't be blank", "is invalid"] }, person.errors.messages)
+    assert_equal({ name: [{ error: :blank }, { error: :invalid }] }, person.errors.details)
+  end
+
   test "errors are marshalable" do
     errors = ActiveModel::Errors.new(Person.new)
     errors.add(:name, :invalid)