Would this circuit work? NPN & PNP transistors ~in parallel:
This doesn't satisfy everything that Dwayne speaks of, but for a simple tester it should serve your purposes.







simulate this circuit &ndash; Schematic created using CircuitLab
Q1 can be either an NPN or a PNP. This is really just testing the polarity of the base terminal by assuming that current will flow out of the base in a pnp and into the base for an npn.

This will dimly light the LEDs depending on the base current the transistor can handle. If you need more brightness, I would go ahead and use an op-amp or a comparator to detect current flow between the voltage divider and Q1. That might look like this:







simulate this circuit
Note that this circuit doesn't detect if there's a short in your transistor or not so it's still a rudimentary transistor checker.