1 files changed, 2 insertions, 2 deletions
diff --git a/activerecord/test/cases/adapters/sqlite3/sqlite3_adapter_test.rb b/activerecord/test/cases/adapters/sqlite3/sqlite3_adapter_test.rb
index 9a812e325e..cf0c37f70c 100644
--- a/activerecord/test/cases/adapters/sqlite3/sqlite3_adapter_test.rb
+++ b/activerecord/test/cases/adapters/sqlite3/sqlite3_adapter_test.rb
@@ -165,7 +165,7 @@ module ActiveRecord
             data binary
           )
         eosql
-        str = "\x80".force_encoding("ASCII-8BIT")
+        str = "\x80".dup.force_encoding("ASCII-8BIT")
         binary = DualEncoding.new name: "いただきます！", data: str
         binary.save!
         assert_equal str, binary.data
@@ -174,7 +174,7 @@ module ActiveRecord
       end
 
       def test_type_cast_should_not_mutate_encoding
-        name = "hello".force_encoding(Encoding::ASCII_8BIT)
+        name = "hello".dup.force_encoding(Encoding::ASCII_8BIT)
         Owner.create(name: name)
         assert_equal Encoding::ASCII_8BIT, name.encoding
       ensure