diff --git a/tests/hwsim/hostapd.py b/tests/hwsim/hostapd.py
index 879059e66..19b9fad2b 100644
--- a/tests/hwsim/hostapd.py
+++ b/tests/hwsim/hostapd.py
@@ -46,6 +46,8 @@ class Hostapd:
     def __init__(self, ifname):
         self.ifname = ifname
         self.ctrl = wpaspy.Ctrl(os.path.join(hapd_ctrl, ifname))
+        self.mon = wpaspy.Ctrl(os.path.join(hapd_ctrl, ifname))
+        self.mon.attach()
 
     def request(self, cmd):
         logger.debug(self.ifname + ": CTRL: " + cmd)
@@ -109,6 +111,39 @@ class Hostapd:
         if not "OK" in self.ctrl.request("ENABLE"):
             raise Exception("Failed to disable hostapd interface " + self.ifname)
 
+    def dump_monitor(self):
+        while self.mon.pending():
+            ev = self.mon.recv()
+            logger.debug(self.ifname + ": " + ev)
+
+    def wait_event(self, events, timeout):
+        count = 0
+        while count < timeout * 10:
+            count = count + 1
+            time.sleep(0.1)
+            while self.mon.pending():
+                ev = self.mon.recv()
+                logger.debug(self.ifname + ": " + ev)
+                for event in events:
+                    if event in ev:
+                        return ev
+        return None
+
+    def get_status(self):
+        res = self.request("STATUS")
+        lines = res.splitlines()
+        vals = dict()
+        for l in lines:
+            [name,value] = l.split('=', 1)
+            vals[name] = value
+        return vals
+
+    def get_status_field(self, field):
+        vals = self.get_status()
+        if field in vals:
+            return vals[field]
+        return None
+
 def add_ap(ifname, params):
         logger.info("Starting AP " + ifname)
         hapd_global = HostapdGlobal()
@@ -133,6 +168,7 @@ def add_ap(ifname, params):
             else:
                 hapd.set(f, v)
         hapd.enable()
+        return hapd
 
 def add_bss(phy, ifname, confname, ignore_error=False):
     logger.info("Starting BSS phy=" + phy + " ifname=" + ifname)
diff --git a/tests/hwsim/multi-bss-acs.conf b/tests/hwsim/multi-bss-acs.conf
new file mode 100644
index 000000000..4e1db46c0
--- /dev/null
+++ b/tests/hwsim/multi-bss-acs.conf
@@ -0,0 +1,28 @@
+driver=nl80211
+
+hw_mode=g
+channel=0
+ieee80211n=1
+
+interface=wlan3
+ctrl_interface=/var/run/hostapd
+
+ssid=bss-1
+
+bss=wlan3-2
+bssid=02:00:00:00:03:01
+ctrl_interface=/var/run/hostapd
+ssid=bss-2
+wpa=2
+wpa_key_mgmt=WPA-PSK
+rsn_pairwise=CCMP
+wpa_passphrase=12345678
+
+bss=wlan3-3
+bssid=02:00:00:00:03:02
+ctrl_interface=/var/run/hostapd
+ssid=bss-3
+wpa=1
+wpa_key_mgmt=WPA-PSK
+rsn_pairwise=TKIP
+wpa_passphrase=qwertyuiop
diff --git a/tests/hwsim/test_ap_acs.py b/tests/hwsim/test_ap_acs.py
new file mode 100644
index 000000000..d456b8106
--- /dev/null
+++ b/tests/hwsim/test_ap_acs.py
@@ -0,0 +1,68 @@
+#!/usr/bin/python
+#
+# Test cases for automatic channel selection with hostapd
+# Copyright (c) 2013, Jouni Malinen <j@w1.fi>
+#
+# This software may be distributed under the terms of the BSD license.
+# See README for more details.
+
+import logging
+logger = logging.getLogger()
+
+import hostapd
+
+def wait_acs(hapd):
+    ev = hapd.wait_event(["ACS-STARTED", "ACS-COMPLETED", "ACS-FAILED",
+                          "AP-ENABLED"], timeout=5)
+    if not ev:
+        raise Exception("ACS start timed out")
+    if "ACS-STARTED" not in ev:
+        raise Exception("Unexpected ACS event")
+
+    state = hapd.get_status_field("state")
+    if state != "ACS":
+        raise Exception("Unexpected interface state")
+
+    ev = hapd.wait_event(["ACS-COMPLETED", "ACS-FAILED", "AP-ENABLED"],
+                         timeout=20)
+    if not ev:
+        raise Exception("ACS timed out")
+    if "ACS-COMPLETED" not in ev:
+        raise Exception("Unexpected ACS event")
+
+    ev = hapd.wait_event(["AP-ENABLED"], timeout=5)
+    if not ev:
+        raise Exception("AP setup timed out")
+
+    state = hapd.get_status_field("state")
+    if state != "ENABLED":
+        raise Exception("Unexpected interface state")
+
+def test_ap_acs(dev, apdev):
+    """Automatic channel selection"""
+    params = hostapd.wpa2_params(ssid="test-acs", passphrase="12345678")
+    params['channel'] = '0'
+    hapd = hostapd.add_ap(apdev[0]['ifname'], params)
+    wait_acs(hapd)
+
+    freq = hapd.get_status_field("freq")
+    if int(freq) < 2400:
+        raise Exception("Unexpected frequency")
+
+    dev[0].connect("test-acs", psk="12345678", scan_freq=freq)
+
+def test_ap_multi_bss_acs(dev, apdev):
+    """hostapd start with a multi-BSS configuration file using ACS"""
+    ifname = apdev[0]['ifname']
+    hostapd.add_iface(ifname, 'multi-bss-acs.conf')
+    hapd = hostapd.Hostapd(ifname)
+    hapd.enable()
+    wait_acs(hapd)
+
+    freq = hapd.get_status_field("freq")
+    if int(freq) < 2400:
+        raise Exception("Unexpected frequency")
+
+    dev[0].connect("bss-1", key_mgmt="NONE", scan_freq=freq)
+    dev[1].connect("bss-2", psk="12345678", scan_freq=freq)
+    dev[2].connect("bss-3", psk="qwertyuiop", scan_freq=freq)