Get valid pair by priority

lib/ex_ice/priv/checklist.ex

@@ -25,8 +25,10 @@ defmodule ExICE.Priv.Checklist do
   @spec get_valid_pair(t()) :: CandidatePair.t() | nil
   def get_valid_pair(checklist) do
     checklist
-    |> Enum.find({nil, nil}, fn {_id, pair} -> pair.valid? end)
-    |> elem(1)
+    |> Stream.map(fn {_id, pair} -> pair end)
+    |> Stream.filter(fn pair -> pair.valid? end)
+    |> Enum.sort_by(fn pair -> pair.priority end, :desc)
+    |> Enum.at(0)
   end
 
   @spec find_pair(t(), CandidatePair.t()) :: CandidatePair.t() | nil

test/candidate_test.exs

@@ -4,7 +4,6 @@ defmodule ExICE.CandidateTest do
   alias ExICE.Candidate
 
   test "candidate's foundation" do
-    # FIXME socket shouldn't be nil
     ip = {192, 168, 1, 1}
     port = 12_345
 

test/priv/checklist_test.exs

@@ -0,0 +1,52 @@
+defmodule ExICE.Priv.ChecklistTest do
+  use ExUnit.Case, async: true
+
+  alias ExICE.Priv.{Candidate, CandidatePair, Checklist}
+
+  test "get_valid_pair/1" do
+    local_addr = {192, 168, 0, 1}
+    local_port = 8445
+    remote_addr = {192, 168, 0, 2}
+    remote_port = 8445
+    remote_srflx_addr = {192, 168, 0, 3}
+    remote_srflx_port = 8445
+
+    local_host_cand =
+      Candidate.Host.new(
+        address: local_addr,
+        port: local_port,
+        base_address: local_addr,
+        base_port: local_port,
+        socket: nil
+      )
+
+    remote_host_cand =
+      ExICE.Candidate.new(:host,
+        address: local_addr,
+        port: local_port,
+        base_address: local_addr,
+        base_port: local_port
+      )
+
+    remote_srflx_cand =
+      ExICE.Candidate.new(:srflx,
+        address: remote_srflx_addr,
+        port: remote_srflx_port,
+        base_address: remote_addr,
+        base_port: remote_port
+      )
+
+    host_pair =
+      CandidatePair.new(local_host_cand, remote_host_cand, :controlling, :succeeded, valid?: true)
+
+    srflx_pair =
+      CandidatePair.new(local_host_cand, remote_srflx_cand, :controlling, :succeeded,
+        valid?: true
+      )
+
+    checklist = %{host_pair.id => host_pair, srflx_pair.id => srflx_pair}
+
+    assert host_pair.priority > srflx_pair.priority
+    assert Checklist.get_valid_pair(checklist) == host_pair
+  end
+end