merge `bittorrent-client` into this module

When I started the WebTorrent project I thought there were going to
need to be two separate client implementations (bittorrent-client and
webtorrent-client) that would get tied together in a higher-level
module.

Fortunately, this was not necessary because of the awesome “browser”
field support in browserify. By substituting just a few modules, we can
make the same module (webtorrent) work in node AND the browser, with
the same codebase!

So, from now on, you can just `require(‘webtorrent’)` in node or the
browser, and it will just work. You can also `npm install webtorrent`
if you want to use bittorrent in a node app or script. Lastly, you can
`npm install webtorrent -g` if you want to use webtorrent as a command
line app (it installs a `webtorrent` command).

1 files changed, 113 insertions, 0 deletions

diff --git a/test/rarity-map.js b/test/rarity-map.js
new file mode 100644
index 0000000..5e04ddc
--- /dev/null
+++ b/test/rarity-map.js
@@ -0,0 +1,113 @@
+var RarityMap = require('../lib/rarity-map')
+var BitField = require('bitfield')
+var Swarm = require('bittorrent-swarm')
+var EventEmitter = require('events').EventEmitter
+var test = require('tape')
+var hat = require('hat')
+
+var infoHash = 'd2474e86c95b19b8bcfdb92bc12c9d44667cfa36'
+var peerId1 = '-WW0001-' + hat(48)
+
+test('Rarity map usage', function (t) {
+  t.plan(16)
+
+  var swarm = new Swarm(infoHash, peerId1)
+  var numPieces = 4
+  swarm.wires = [ new EventEmitter(), new EventEmitter() ]
+  swarm.wires.forEach(function (wire) {
+    wire.peerPieces = new BitField(numPieces)
+  })
+  var rarityMap = new RarityMap(swarm, numPieces)
+
+  function validateInitial () {
+    // note that getRarestPiece will return a random piece since they're all equal
+    // so repeat the test several times to reasonably ensure its correctness.
+    var piece = rarityMap.getRarestPiece()
+    t.ok(piece >= 0 && piece < numPieces)
+
+    piece = rarityMap.getRarestPiece()
+    t.ok(piece >= 0 && piece < numPieces)
+
+    piece = rarityMap.getRarestPiece()
+    t.ok(piece >= 0 && piece < numPieces)
+
+    piece = rarityMap.getRarestPiece()
+    t.ok(piece >= 0 && piece < numPieces)
+  }
+
+  // test initial / empty case
+  validateInitial()
+
+  rarityMap.recalculate()
+
+  // test initial / empty case after recalc
+  validateInitial()
+
+  function setPiece (wire, index) {
+    wire.peerPieces.set(index)
+    wire.emit('have', index)
+  }
+
+  setPiece(swarm.wires[0], 0)
+  setPiece(swarm.wires[1], 0)
+
+  setPiece(swarm.wires[0], 1)
+  setPiece(swarm.wires[1], 3)
+
+  // test rarest piece after setting pieces and handling 'have' events
+  var piece = rarityMap.getRarestPiece()
+  t.equal(piece, 2)
+
+  rarityMap.recalculate()
+
+  // test rarest piece after recalc to ensure its the same
+  piece = rarityMap.getRarestPiece()
+  t.equal(piece, 2)
+
+  function addWire () {
+    var wire = new EventEmitter()
+    wire.peerPieces = new BitField(numPieces)
+    wire.peerPieces.set(1)
+    wire.peerPieces.set(2)
+    swarm.wires.push(wire)
+    swarm.emit('wire', wire)
+  }
+
+  addWire()
+  addWire()
+
+  // test rarest piece after adding wires
+  piece = rarityMap.getRarestPiece()
+  t.equal(piece, 3)
+
+  rarityMap.recalculate()
+
+  // test rarest piece after adding wires and recalc
+  piece = rarityMap.getRarestPiece()
+  t.equal(piece, 3)
+
+  function removeWire (index) {
+    var wire = swarm.wires.splice(index, 1)[0]
+    wire.emit('close')
+  }
+
+  removeWire(3)
+  removeWire(1)
+
+  // test rarest piece after removing wires
+  piece = rarityMap.getRarestPiece()
+  t.equal(piece, 3)
+
+  rarityMap.recalculate()
+
+  // test rarest piece after removing wires and recalc
+  piece = rarityMap.getRarestPiece()
+  t.equal(piece, 3)
+
+  // test piece filter func
+  piece = rarityMap.getRarestPiece(function (i) { return i <= 1 })
+  t.equal(piece, 0)
+
+  piece = rarityMap.getRarestPiece(function (i) { return i === 1 || i === 2 })
+  t.equal(piece, 2)
+})