Mobly is a Python-based test framework that specializes in supporting test cases that require multiple devices, complex environments, or custom hardware setups. Examples:
- P2P data transfer between two devices
- Conference calls across three phones
- Wearable device interacting with a phone
- Internet-Of-Things devices interacting with each other
- Testing RF characteristics of devices with special equipment
Mobly can support many different types of devices and equipment, and it's easy to plug your own device or custom equipment/service into Mobly.
Mobly comes with a set of libs to control common devices like Android devices.
While developed by Googlers, Mobly is not an official Google product.
Writing and executing simple test cases that use Android devices. We are focusing on Android devices here since they are the most accessible devices. Mobly supports various devices and you can also use your own custom hardware/equipment.
- A computer with 2 USB ports (or a USB hub).
- Mobly package and its system dependencies installed on the computer.
- One or two Android devices with the app SL4A* installed.
- A working adb setup. To check, connect one Android device to the computer
and make sure it has "USB debugging" enabled. Make sure the device shows up
in the list printed by
adb devices.
* You can get SL4A from the
Android repo, under
project <aosp>/external/sl4a
It can be built like a regular system app with mm commands. It needs to be
signed with the build you use on your Android devices.
- adb (1.0.36+ recommended)
- python2.7 or python3.4+
- python-setuptools
If you use Python3, use pip3 and python3 (or python3.x) accordingly
throughout this tutorial.
Mobly is compatible with both python 3.4+ and python 2.7.
You can install the released package from pip
$ pip install mobly
or download the source to use the bleeding edge:
$ python setup.py install
You may need sudo for the above commands if your system has certain permission
restrictions.
Let's start with the simple example of posting "Hello World" on the Android device's screen. Create the following files:
sample_config.json
{
"testbed":
[
{
"_description": "A testbed where adb will find Android devices.",
"name": "SampleTestBed",
"AndroidDevice": "*"
}
],
"logpath": "/tmp/logs"
}hello_world_test.py
from mobly import base_test
from mobly import test_runner
from mobly.controllers import android_device
class HelloWorldTest(base_test.BaseTestClass):
def setup_class(self):
# Registering android_device controller module declares the test's
# dependency on Android device hardware. By default, we expect at least one
# object is created from this.
self.ads = self.register_controller(android_device)
self.dut = self.ads[0]
def test_hello(self):
self.dut.sl4a.makeToast('Hello World!')
if __name__ == "__main__":
test_runner.main()To execute:
$ python hello_world_test.py -c sample_config.json
Expect
A "Hello World!" toast notification appears on your device's screen.
Within SampleTestBed, we used "AndroidDevice" : "*" to tell the test runner to
automatically find all connected Android devices. You can also specify
particular devices by serial number and attach extra attributes to the object:
"AndroidDevice": [
{"serial": "xyz", "phone_number": "123456"},
{"serial": "abc", "label": "golden_device"},
]We have multiple tests written in a test script, and we only want to execute a subset of them.
hello_world_test.py
from mobly import base_test
from mobly import test_runner
from mobly.controllers import android_device
class HelloWorldTest(base_test.BaseTestClass):
def setup_class(self):
self.ads = self.register_controller(android_device)
self.dut = self.ads[0]
def test_hello(self):
self.dut.sl4a.makeToast('Hello World!')
def test_bye(self):
self.dut.sl4a.makeToast('Goodbye!')
if __name__ == "__main__":
test_runner.main()To execute:
$ python hello_world_test.py -c sample_config.json --test_case test_bye
Expect
A "Goodbye!" toast notification appears on your device's screen.
You can dictate what test cases to execute within a test script and their execution order, shown below:
$ python hello_world_test.py -c sample_config.json --test_case test_bye test_hello test_bye
Expect
Toast notifications appear on your device's screen in the following order: "Goodbye!", "Hello World!", "Goodbye!".
You could specify user parameters to be passed into your test class in the config file.
In the following config, we added a user parameter favorite_food.
sample_config.json
{
"testbed":
[
{
"name" : "SampleTestBed",
"AndroidDevice" : "*"
}
],
"logpath" : "/tmp/logs",
"favorite_food" : "Green eggs and ham."
}In the test script, you could access the user parameter:
def test_favorite_food(self):
food = self.user_params.get('favorite_food')
if food:
self.dut.sl4a.makeToast("I'd like to eat %s." % food)
else:
self.dut.sl4a.makeToast("I'm not hungry.")Multiple test beds can be configured in one configuration file.
sample_config.json
{
"testbed":[
{
"name" : "XyzTestBed",
"AndroidDevice" : [{"serial": "xyz", "phone_number": "123456"}]
},
{
"name" : "AbcTestBed",
"AndroidDevice" : [{"serial": "abc", "label": "golden_device"}]
}
],
"logpath" : "/tmp/logs",
"favorite_food": "green eggs and ham"
}You can choose which one to execute on with the command line argument
--test_bed:
$ python hello_world_test.py -c sample_config.json --test_bed AbcTestBed
Expect
A "Hello World!" and a "Goodbye!" toast notification appear on your device's screen.
In this example, we use one Android device to discover another Android device via bluetooth. This test demonstrates several essential elements in test writing, like logging and asserts.
sample_config.json
{
"testbed":[
{
"name" : "TwoDeviceTestBed",
"AndroidDevice" : [{"serial": "xyz", "label": "dut"},
{"serial": "abc", "label": "discoverer"}]
}
],
"logpath" : "/tmp/logs",
"bluetooth_name": "MagicBluetooth",
"bluetooth_timeout": 5
}sample_test.py
from mobly import base_test
from mobly import test_runner
from mobly.controllerse import android_device
class HelloWorldTest(base_test.BaseTestClass):
def setup_class(self):
# Registering android_device controller module, and declaring that the test
# requires at least two Android devices.
self.ads = self.register_controller(android_device, min_number=2)
self.dut = android_device.get_device(self.ads, label="dut")
self.discoverer = android_device.get_device(self.ads, label="discoverer")
self.dut.ed.clear_all_events()
self.discoverer.ed.clear_all_events()
def setup_test(self):
# Make sure bluetooth is on
self.dut.sl4a.bluetoothToggleState(True)
self.discoverer.sl4a.bluetoothToggleState(True)
self.dut.ed.pop_event(event_name='BluetoothStateChangedOn',
timeout=10)
self.discoverer.ed.pop_event(event_name='BluetoothStateChangedOn',
timeout=10)
if (not self.dut.sl4a.bluetoothCheckState() or
not self.discoverer.sl4a.bluetoothCheckState()):
asserts.abort_class('Could not turn on Bluetooth on both devices.')
# Set the name of device #1 and verify the name properly registered.
self.dut.sl4a.bluetoothSetLocalName(self.bluetooth_name)
asserts.assert_equal(self.dut.sl4a.bluetoothGetLocalName(),
self.bluetooth_name,
'Failed to set bluetooth name to %s on %s' %
(self.bluetooth_name, self.dut.serial))
def test_bluetooth_discovery(self):
# Make dut discoverable.
self.dut.sl4a.bluetoothMakeDiscoverable()
scan_mode = self.dut.sl4a.bluetoothGetScanMode()
asserts.assert_equal(
scan_mode, 3, # 3 signifies CONNECTABLE and DISCOVERABLE
'Android device %s failed to make blueooth discoverable.' %
self.dut.serial)
# Start the discovery process on #discoverer.
self.discoverer.ed.clear_all_events()
self.discoverer.sl4a.bluetoothStartDiscovery()
self.discoverer.ed.pop_event(
event_name='BluetoothDiscoveryFinished',
timeout=self.bluetooth_timeout)
# The following log entry demonstrates AndroidDevice log object, which
# prefixes log entries with "[AndroidDevice|<serial>] "
self.discoverer.log.info('Discovering other bluetooth devices.')
# Get a list of discovered devices
discovered_devices = self.discoverer.sl4a.bluetoothGetDiscoveredDevices()
self.discoverer.log.info('Found devices: %s', discovered_devices)
matching_devices = [d for d in discovered_devices
if d.get('name') == self.bluetooth_name]
if not matching_devices:
asserts.fail('Android device %s did not discover %s.' %
(self.discoverer.serial, self.dut.serial))
self.discoverer.log.info('Discovered at least 1 device named '
'%s: %s', self.bluetooth_name, matching_devices)
if __name__ == "__main__":
test_runner.main()One will notice that this is not the most robust test (another nearby device could be using the same name), but in the interest of simplicity, we've limited the number of RPCs sent to each Android device to just two:
- For
self.dut, we asked it to make itself discoverable and checked that it did it. - For
self.discoverer, we asked it to start scanning for nearby bluetooth devices, and then we pulled the list of devices seen.
There's potentially a lot more we could do to write a thorough test (e.g., check the hardware address, see whether we can pair devices, transfer files, etc.).
You'll notice above that we've used self.{device_alias}.ed.pop_event(). The
ed attribute of an Android device object is an EventDispatcher, which provides
APIs to interact with async events.
For example, pop_event is a function which will block until either a
specified event is seen or the call times out, and by using it we avoid the use
of busy loops that constantly check the device state. For more, see the APIs in
mobly.controllers.android_device_lib.event_dispatcher.