What is the reason for connecting a capacitor across a normal blocking diode? is this a snubber circuit?

Question

How would you test a capacitor connected in a circuit without actually disconnecting it from the circuit?

Answer 1

To short the transient spikes so that the diode does not burn out.

Answer 2

What TAT says is true for a flyback or damping diode.  

For a Blocking diode, capacitance is added because the reverse bias capacitance of the diode is too small, by itself, to pass the required AC signal.  The two capacitances in parallel provide sufficient (low) impedance to pass the signal.

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