The dispatch test matched source patterns without checking returned
requests. Load the complete plugin and exercise its request preprocessing
with fixture database rows and the real service-node mapping code.
Check destination filtering, network regeneration, self-dispatch guards,
request contents and hierarchical network errors. Run each case in a fresh
process so lexical option state cannot leak between fixtures.
Assert that a node-targeted makedhcp maps its nodes to their service nodes and
skips the ones serving none of them, that regenerating the networks with -n stays
exempt because a dynamic range is not tied to a node, and that an unmapped
noderange still reaches every service node instead of none.
Also pin the two conditions the loop already had, so restricting the fan-out does
not quietly drop the self dispatch guards.