A system for testing a subterranean formation penetrated by a well includes a downhole tool configured to be coupled to a work string that includes a tool body having a longitudinal bore for circulating a fluid and at least one aperture configured to receive at least one module. The system further includes a plurality of modules that are each configured to engage the at least one aperture and at least one cavity configured for receiving a probe, and a plurality of probes that each include at least one orifice configured for testing the formation, wherein a first of the plurality of probes has a first configuration and a second of the plurality of probes has a second configuration.