/**
  * Test basic usage works
  */
 public function testGenerate()
 {
     $a = MWCryptHKDF::generateHex(64);
     $b = MWCryptHKDF::generateHex(64);
     $this->assertTrue(strlen($a) == 64, "MWCryptHKDF produced fewer bytes than expected");
     $this->assertTrue(strlen($b) == 64, "MWCryptHKDF produced fewer bytes than expected");
     $this->assertFalse($a == $b, "Two runs of MWCryptHKDF produced the same result.");
 }