func getNode(t *testing.T, nodes map[string]storage.RangeTreeNode, testName string, key roachpb.RKey) (storage.RangeTreeNode, bool) {
if key != nil {
if node, ok := nodes[key.String()]; !ok {
t.Errorf("%s: could not locate node with key %s", testName, key)
} else {
return node, ok
}
}
return storage.RangeTreeNode{}, false
}