function testIsValidRequiredField()
 {
     $f = new Tracker_FormElement_Field_FloatTestVersion();
     $f->setReturnValue('isRequired', true);
     $a = new MockTracker_Artifact();
     $this->assertTrue($f->isValid($a, 2));
     $this->assertTrue($f->isValid($a, 789));
     $this->assertTrue($f->isValid($a, 1.23));
     $this->assertTrue($f->isValid($a, -1.45));
     $this->assertTrue($f->isValid($a, 0));
     $this->assertTrue($f->isValid($a, 0.0));
     $this->assertTrue($f->isValid($a, '56.789'));
     $this->assertFalse($f->isValid($a, 'toto'));
     $this->assertFalse($f->isValid($a, '12toto'));
     $this->assertFalse($f->isValidRegardingRequiredProperty($a, ''));
     $this->assertFalse($f->isValidRegardingRequiredProperty($a, null));
 }