public function testMergeKeywords()
{
// Add a keyword.
$this->cache->mergeKeywords('test')->put('key1', 'newValue', 60);
$this->assertEquals(['key1'], $this->cache->get('keyword[test]'));
$this->assertEquals(['key1'], $this->cache->get('keyword[keyword1]'));
$this->assertEquals(['key1', 'key2'], $this->cache->get('keyword[keyword2]'));
$this->assertEquals(['keyword1', 'keyword2', 'test'], $this->cache->get('keyword_index[key1]'));
// Try existing keywords; should do nothing.
$this->cache->mergeKeywords('keyword3')->forever('key3', 'value3');
$this->assertEquals(['key2', 'key3'], $this->cache->get('keyword[keyword3]'));
$this->assertEquals(['key3', 'key4'], $this->cache->get('keyword[keyword4]'));
$this->assertEquals(['keyword3', 'keyword4'], $this->cache->get('keyword_index[key3]'));
// Try empty; should do nothing.
$this->cache->mergeKeywords([])->forever('key3', 'value3');
$this->assertEquals(['key2', 'key3'], $this->cache->get('keyword[keyword3]'));
$this->assertEquals(['key3', 'key4'], $this->cache->get('keyword[keyword4]'));
$this->assertEquals(['keyword3', 'keyword4'], $this->cache->get('keyword_index[key3]'));
}