1 files changed, 45 insertions, 0 deletions
diff --git a/activerecord/test/cases/adapters/mysql2/datetime_precision_quoting_test.rb b/activerecord/test/cases/adapters/mysql2/datetime_precision_quoting_test.rb
new file mode 100644
index 0000000000..e349c67c93
--- /dev/null
+++ b/activerecord/test/cases/adapters/mysql2/datetime_precision_quoting_test.rb
@@ -0,0 +1,45 @@
+require "cases/helper"
+
+class Mysql2DatetimePrecisionQuotingTest < ActiveRecord::Mysql2TestCase
+  setup do
+    @connection = ActiveRecord::Base.connection
+  end
+
+  test 'microsecond precision for MySQL gte 5.6.4' do
+    stub_version '5.6.4'
+    assert_microsecond_precision
+  end
+
+  test 'no microsecond precision for MySQL lt 5.6.4' do
+    stub_version '5.6.3'
+    assert_no_microsecond_precision
+  end
+
+  test 'microsecond precision for MariaDB gte 5.3.0' do
+    stub_version '5.5.5-10.1.8-MariaDB-log'
+    assert_microsecond_precision
+  end
+
+  test 'no microsecond precision for MariaDB lt 5.3.0' do
+    stub_version '5.2.9-MariaDB'
+    assert_no_microsecond_precision
+  end
+
+  private
+    def assert_microsecond_precision
+      assert_match_quoted_microsecond_datetime(/\.000001\z/)
+    end
+
+    def assert_no_microsecond_precision
+      assert_match_quoted_microsecond_datetime(/\d\z/)
+    end
+
+    def assert_match_quoted_microsecond_datetime(match)
+      assert_match match, @connection.quoted_date(Time.now.change(usec: 1))
+    end
+
+    def stub_version(full_version_string)
+      @connection.stubs(:full_version).returns(full_version_string)
+      @connection.remove_instance_variable(:@version) if @connection.instance_variable_defined?(:@version)
+    end
+end