diff --git a/examples/gtk3/libnice_simple_test.nim b/examples/gtk3/libnice_simple_test.nim
new file mode 100644
index 0000000..f177026
--- /dev/null
+++ b/examples/gtk3/libnice_simple_test.nim
@@ -0,0 +1,122 @@
+# nim c libnice_simple_test.nim
+#
+#  Test code for libnice.
+#  If test succeeded, it prints "Test success".
+#  You don't need to run 2 processes of this program to test.
+
+when (compiles do: import gintro/gtk):
+  import gintro/[gtk, glib, gobject, gio, nice]
+else:
+  import gintro/[dummygtk, glib, gobject, gio, nice] # For system has glib but no gtk
+
+import strformat
+
+const
+  ltestMessage = "some test message"
+  rtestMessage = "random text for test"
+
+var
+  gloop: glib.MainLoop
+  lagent, ragent: nice.Agent
+  lstreamId, rstreamId: int
+  gatheringCount, recvCount: int
+
+proc toIntVal(i: int): Value =
+  let gtype = typeFromName("gint")
+  discard init(result, gtype)
+  setInt(result, i)
+
+proc cbCandidateGatheringDone(agent: nice.Agent; streamId: int) =
+  proc copyCandidates(src, dst: nice.Agent; srcStreamId, dstStreamId: int) =
+    var
+      ufrag: string
+      password: string
+
+    doAssert src.getLocalCredentials(srcStreamId, ufrag, password)
+    doAssert dst.setRemoteCredentials(dstStreamId, ufrag, password)
+    var cands: seq[Candidate] = src.getLocalCandidates(srcStreamId, 1)
+    for c in cands.mitems:
+      c.setStreamID(dstStreamId.uint32)
+      c.setComponentID(1)
+    doAssert cands.len != 0
+    doAssert dst.setRemoteCandidates(dstStreamId, 1, cands) > 0
+
+  doAssert agent == lagent or agent == ragent
+  doAssert gatheringCount in (0..1)
+
+  if gatheringCount == 1:
+    copyCandidates(lagent, ragent, lstreamId, rstreamId)
+    copyCandidates(ragent, lagent, rstreamId, lstreamId)
+
+  inc gatheringCount
+
+proc cbComponentStateChanged(agent: nice.Agent; streamId: int; componentId: int; state: int) =
+  doAssert agent == lagent or agent == ragent
+
+  let stat = ComponentState(state)
+  echo &"SIGNAL: state changed {streamId}, {componentId}, {stat}"
+
+  case stat
+  of ComponentState.ready:
+    if agent == lagent:
+      doAssert agent.send(streamId, componentId, ltestMessage.len, ltestMessage.cstring) == ltestMessage.len
+    else:
+      doAssert agent.send(streamId, componentId, rtestMessage.len, rtestMessage.cstring) == rtestMessage.len
+  of ComponentState.failed:
+    gloop.quit
+  else:
+    discard
+
+proc cbNiceRecv(agent: nice.Agent; streamID: cuint; componentID: cuint; len: cuint; buf: cstring) =
+  doAssert agent.impl == lagent.impl or agent.impl == ragent.impl
+  if agent.impl == lagent.impl:
+    doAssert len == rtestMessage.len
+    doAssert equalMem(buf, rtestMessage.cstring, len)
+    echo "lagent received test message"
+  else:
+    doAssert len == ltestMessage.len
+    doAssert equalMem(buf, ltestMessage.cstring, len)
+    echo "ragent received test message"
+
+  doAssert recvCount in (0..1)
+  if recvCount == 1:
+    gloop.quit
+  inc recvCount
+
+proc main =
+  gio.networkingInit()
+
+  
+  gloop = newMainLoop(nil, false)
+
+  lagent = nice.newAgent(glib.getContext(gloop), nice.CompatibilityRfc5245)
+  ragent = nice.newAgent(glib.getContext(gloop), nice.CompatibilityRfc5245)
+
+  doAssert lagent != nil and ragent != nil
+
+  lagent.setProperty("controlling-mode", toIntVal(0))
+  ragent.setProperty("controlling-mode", toIntVal(1))
+
+  lagent.connect("candidate-gathering-done", cbCandidateGatheringDone)
+  ragent.connect("candidate-gathering-done", cbCandidateGatheringDone)
+  lagent.connect("component-state-changed", cbComponentStateChanged)
+  ragent.connect("component-state-changed", cbComponentStateChanged)
+
+  lstreamId = lagent.addStream(1)
+  rstreamId = ragent.addStream(1)
+  doAssert lstreamId != 0 and rstreamId != 0
+
+  lagent.attachRecv(lstreamId.cuint, 1, getContext(gloop), cbNiceRecv)
+  ragent.attachRecv(rstreamId.cuint, 1, getContext(gloop), cbNiceRecv)
+
+  doAssert gatherCandidates(lagent, lstreamId)
+  doAssert gatherCandidates(ragent, rstreamId)
+
+  gloop.run
+
+  doAssert gatheringCount == 2
+  doAssert recvCount == 2
+
+  echo "Test success"
+
+main()