An apparatus and method for obtaining samples of pristine formation or formation fluid, using a work string designed for performing other downhole work such as drilling, workover operations, or re-entry operations. An extendable element extends against the formation wall to obtain the pristine formation or fluid sample. While the test tool is in a standby condition, the extendable element is withdrawn within the work string, protected by other structure from damage during operation of the work string. The test apparatus is mounted on a sliding, non-rotating, sleeve on the work string.