function test( v ) {
	if (
		!isNull( v ) &&
		!isNonNegativeInteger( v )
	) {
		return new TypeError( format( 'invalid assignment. `%s` must be a nonnegative integer or null. Value: `%s`.', 'numTicks', v ) );
	}
	return null;
}
Validates `numTicks`.

@private
@param {*} v - value to test
@returns {(Error|null)} error object or null