1 files changed, 16 insertions, 4 deletions
diff --git a/activerecord/test/cases/core_test.rb b/activerecord/test/cases/core_test.rb
index 6e7ae2efb4..36e3d543cd 100644
--- a/activerecord/test/cases/core_test.rb
+++ b/activerecord/test/cases/core_test.rb
@@ -30,13 +30,18 @@ class CoreTest < ActiveRecord::TestCase
     assert_equal %(#<Topic id: 1, title: "The First Topic">), Topic.all.merge!(select: "id, title", where: "id = 1").first.inspect
   end
 
+  def test_inspect_instance_with_non_primary_key_id_attribute
+    topic = topics(:first).becomes(TitlePrimaryKeyTopic)
+    assert_match(/id: 1/, topic.inspect)
+  end
+
   def test_inspect_class_without_table
     assert_equal "NonExistentTable(Table doesn't exist)", NonExistentTable.inspect
   end
 
   def test_pretty_print_new
     topic = Topic.new
-    actual = "".dup
+    actual = +""
     PP.pp(topic, StringIO.new(actual))
     expected = <<~PRETTY
       #<Topic:0xXXXXXX
@@ -65,7 +70,7 @@ class CoreTest < ActiveRecord::TestCase
 
   def test_pretty_print_persisted
     topic = topics(:first)
-    actual = "".dup
+    actual = +""
     PP.pp(topic, StringIO.new(actual))
     expected = <<~PRETTY
       #<Topic:0x\\w+
@@ -93,7 +98,7 @@ class CoreTest < ActiveRecord::TestCase
 
   def test_pretty_print_uninitialized
     topic = Topic.allocate
-    actual = "".dup
+    actual = +""
     PP.pp(topic, StringIO.new(actual))
     expected = "#<Topic:XXXXXX not initialized>\n"
     assert actual.start_with?(expected.split("XXXXXX").first)
@@ -106,8 +111,15 @@ class CoreTest < ActiveRecord::TestCase
         "inspecting topic"
       end
     end
-    actual = "".dup
+    actual = +""
     PP.pp(subtopic.new, StringIO.new(actual))
     assert_equal "inspecting topic\n", actual
   end
+
+  def test_pretty_print_with_non_primary_key_id_attribute
+    topic = topics(:first).becomes(TitlePrimaryKeyTopic)
+    actual = +""
+    PP.pp(topic, StringIO.new(actual))
+    assert_match(/id: 1/, actual)
+  end
 end