Repulsion is defined as a force that tends to separate two objects, i.e the force between two like electric charges or magnetic poles.
Example : The two electrons tend to move away from each other as they both have negative charge, defines the repulsion between them.
Repulsion as the true test of electrification:
Electrification is known as the process that produces electric charges on any object.
The force of electrostatic attraction can be observed between two bodies when they are oppositely charged and also when one is charged and the other uncharged.
In the second case, the attraction occurs due to the induced charges on the unloaded body.
however, in the second case, repulsion is observed only when two bodies have like charges and this means that the bodies must be charged.
Hence repulsion is the surest test of electrification as it ensures that both of the bodies are charged.
Therefore, yes, repulsion is a true test of electrification.