Improve GPRS test scripts

Catch some errors and add a script for removing contexts.

test/activate-context

@@ -35,4 +35,8 @@ for path in properties["Modems"]:
 	context = dbus.Interface(bus.get_object('org.ofono', path),
 					'org.ofono.PrimaryDataContext')
 
-	context.SetProperty("Active", dbus.Boolean(1))
+	try:
+		context.SetProperty("Active", dbus.Boolean(1))
+	except dbus.DBusException, e:
+		print "Error activating %s: %s" % (path, str(e))
+		exit(2)

test/create-context

@@ -32,6 +32,10 @@ for path in properties["Modems"]:
 	context = dbus.Interface(bus.get_object('org.ofono', path),
 					'org.ofono.PrimaryDataContext')
 
-	context.SetProperty("AccessPointName", sys.argv[1])
+	try:
+		context.SetProperty("AccessPointName", sys.argv[1])
+	except IndexError:
+		print "Usage: %s <apn_name>" % sys.argv[0]
+		exit(1)
 
 	print "Setting APN of %s to %s" % (path, sys.argv[1])

test/deactivate-context

@@ -33,4 +33,8 @@ for path in properties["Modems"]:
 	context = dbus.Interface(bus.get_object('org.ofono', path),
 					'org.ofono.PrimaryDataContext')
 
-	context.SetProperty("Active", dbus.Boolean(0))
+	try:
+		context.SetProperty("Active", dbus.Boolean(0))
+	except dbus.DBusException, e:
+		print "Error activating %s: %s" % (path, str(e))
+		exit(2)

test/remove-contexts

@@ -0,0 +1,28 @@
+#!/usr/bin/python
+
+import dbus
+
+bus = dbus.SystemBus()
+
+manager = dbus.Interface(bus.get_object('org.ofono', '/'),
+						'org.ofono.Manager')
+
+properties = manager.GetProperties()
+
+for path in properties["Modems"]:
+	modem = dbus.Interface(bus.get_object('org.ofono', path),
+							'org.ofono.Modem')
+
+	properties = modem.GetProperties()
+
+	if "org.ofono.DataConnectionManager" not in properties["Interfaces"]:
+		continue
+
+	connmgr = dbus.Interface(bus.get_object('org.ofono', path),
+					'org.ofono.DataConnectionManager')
+
+	properties = connmgr.GetProperties()
+
+	for path in properties["PrimaryContexts"]:
+		connmgr.RemoveContext(path)
+		print"Removed: [ %s ]" % (path)