What should be the value of the 'tests' attribute according to the JUnit result xml format

For my own unit test framework, I am implementing the ability to output JUnit xml format.

I found this specification: http://ift.tt/1v2CVtF

But I am puzzled by the tests attribute:

<testsuites ...
    tests=""    <!-- total number of successful tests from all testsuites. -->
    ...
  <testsuite ...
      tests=""     <!-- The total number of tests in the suite, required. -->

According to that documentation, this attribute should be implemented differently on the testsuites and testsuite element, as it should only count the number of successful tests on the testsuites element, where it should count all tests on the testsuite element.

Is that the case, or is this documentation misguiding?