Add absolutely minimal implementation of a DHT routing table

ipfs/dht/routing.nim

@@ -0,0 +1,11 @@
+import pkg/libp2p
+
+type
+  RoutingTable* = object
+    peers: seq[PeerInfo]
+
+proc add*(table: var RoutingTable, peer: PeerInfo) =
+  table.peers.add(peer)
+
+proc closest*(table: RoutingTable, id: Cid): seq[PeerInfo] =
+  table.peers

tests/ipfs/testDhtRouting.nim

@@ -0,0 +1,17 @@
+import std/unittest
+import pkg/libp2p
+import pkg/ipfs/ipfsobject
+import pkg/ipfs/dht/routing
+
+suite "DHT routing table":
+
+  test "finds peers closest to some content":
+    let peer1 = PeerInfo(peer: PeerId(data: @[1'u8]))
+    let peer2 = PeerInfo(peer: PeerId(data: @[2'u8]))
+    let contentId = IpfsObject(data: @[]).cid
+
+    var table = RoutingTable()
+    table.add(peer1)
+    table.add(peer2)
+
+    check table.closest(contentId) == @[peer1, peer2]

tests/testAll.nim

@@ -1,6 +1,7 @@
 import ./ipfs/testObject
 import ./ipfs/testChunking
 import ./ipfs/testRepo
+import ./ipfs/testDhtRouting
 import ./ipfs/testIpfs
 
 {.warning[UnusedImport]: off.}