taxonomy_get_term and taxonomy_vocabulary_load cannot be used in testing

Patch attached for review.

This is the test that was failing because of the data leaking inbetween test runs:

class PathautoTaxonomyTokenTestCase extends PathautoTestHelper {
  protected $vocabularies = array();
  protected $terms = array();

  public static function getInfo() {
    return array(
      'name' => 'Pathauto taxonomy tokens',
      'description' => 'Unit tests for the taxonomy tokens provided by Pathauto.',
      'group' => 'Pathauto',
    );
  }

  function setUp() {
    parent::setUp('taxonomy');
    variable_set('pathauto_taxonomy_pattern', 'category/[vocab-raw]/[cat-raw]');
  }

  /**
   * Test the [termpath] token.
   */
  function testTermPath() {
  }

  /**
   * Test the [catpath] token.
   */
  function testCatPath() {
    $vocab = $this->addVocabulary();
    $term1 = $this->addTerm($vocab);
    $this->assertToken('taxonomy', $term1, 'catpath', $term1->name);

    $term2 = $this->addTerm($vocab, array('parent' => $term1->tid));
    $this->assertToken('taxonomy', $term2, 'catpath', "{$term1->name}/{$term2->name}");

    $term3 = $this->addTerm($vocab, array('parent' => $term2->tid));
    $this->assertToken('taxonomy', $term3, 'catpath', "{$term1->name}/{$term2->name}/{$term3->name}");
  }

  /**
   * Test the [catalias] token.
   */
  function testCatAlias() {
    $vocab = $this->addVocabulary();
    $term1 = $this->addTerm($vocab);
    // *** THIS IS WHERE THE TEST FAILED SINCE IT LOADED OLD DATA FOR BOTH VID 1 and TID 1.
    $this->assertToken('taxonomy', $term1, 'catalias', "category/{$vocab->name}/{$term1->name}");
  }

  function addVocabulary(array $vocabulary = array()) {
    $vocabulary += array(
      'name' => drupal_strtolower($this->randomName(5)),
      'nodes' => array('page' => 'page'),
    );
    taxonomy_save_vocabulary($vocabulary);
    return (object) $vocabulary;
  }

  function addTerm(stdClass $vocabulary, array $term = array()) {
    $term += array(
      'name' => drupal_strtolower($this->randomName(5)),
      'vid' => $vocabulary->vid,
    );
    taxonomy_save_term($term);
    return (object) $term;
  }
}

1. Unfortunately is a bug in the code we'd only see when using tests. You could technically do the same thing in a standalone script that can use the Drupal APIs:

// Add a term
$new_term = array('name' => 'First term');
drupal_write_record('term_data', $term);

$loaded_term = taxonomy_get_term($new_term['tid']);
echo "Loaded term " . $loaded_term->name;
// Will print 'Loaded term First term'

// Delete the term
taxonomy_del_term($loaded_term->tid);

// Add another new term
$new_term = array('name' => 'Second term');
drupal_write_record('term_data', $term);

$loaded_term = taxonomy_get_term($new_term['tid']);
echo "Loaded term " . $loaded_term->name;
// Will print 'Loaded term First term' instead of 'Loaded term Second term'.

2. Well it's either we get this into D6 core, or we have to put anything like this into SimpleTests's core patch. It would be easier to fix it in core. But its not my decision to make.

The point is to clear the *entire* cache, not just for the individual term. This works exactly the same as other similar static caching functions in core:

function node_load($param = array(), $revision = NULL, $reset = NULL) {
  static $nodes = array();

  if ($reset) {
    $nodes = array();
  }

So I don't think it's appropriate for a follow-up.