python-periphery/tests/test_pwm.py at master · xrombik/python-periphery · GitHub

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import sys
import periphery
from .asserts import AssertRaises

if sys.version_info[0] == 3:
    raw_input = input

pwm_channel = None
pwm_pin = None


def test_arguments():
    print("Starting arguments test...")

    # Invalid open types
    with AssertRaises(TypeError):
        periphery.PWM("foo", 0)
    with AssertRaises(TypeError):
        periphery.PWM(0, "foo")

    print("Arguments test passed.")


def test_open_close():
    print("Starting open/close test...")

    # Open non-existent PWM channel
    with AssertRaises(ValueError):
        periphery.PWM(9999, pwm_pin)

    # Open non-existent PWM pin
    with AssertRaises(periphery.PWMError):
        periphery.PWM(pwm_channel, 9999)

    # Open legitimate PWM channel/pin
    pwm = periphery.PWM(pwm_channel, pwm_pin)
    assert pwm.channel == pwm_channel
    assert pwm.pin == pwm_pin

    # Set period, check period and frequency
    pwm.period = 1e-3
    assert (pwm.period - 1e-3) < 1e-4
    assert (pwm.frequency - 1000) < 100
    pwm.period = 5e-4
    assert (pwm.period - 5e-4) < 1e-5
    assert (pwm.frequency - 2000) < 100
    # Set frequency, check frequency and period
    pwm.frequency = 1000
    assert (pwm.frequency - 1000) < 100
    assert (pwm.period - 1e-3) < 1e-4
    pwm.frequency = 2000
    assert (pwm.frequency - 2000) < 100
    assert (pwm.period - 5e-4) < 1e-5
    # Set duty cycle, check duty cycle
    pwm.duty_cycle = 0.25
    assert (pwm.duty_cycle - 0.25) < 1e-3
    pwm.duty_cycle = 0.50
    assert (pwm.duty_cycle - 0.50) < 1e-3
    pwm.duty_cycle = 0.75
    assert (pwm.duty_cycle - 0.75) < 1e-3
    # Set polarity, check polarity
    pwm.polarity = "normal"
    assert pwm.polarity == "normal"
    pwm.polarity = "inversed"
    assert pwm.polarity == "inversed"
    # Set enabled, check enabled
    pwm.enabled = True
    assert pwm.enabled == True
    pwm.enabled = False
    assert pwm.enabled == False
    # Use enable()/disable(), check enabled
    pwm.enable()
    assert pwm.enabled == True
    pwm.disable()
    assert pwm.enabled == False

    # Set invalid polarity
    with AssertRaises(ValueError):
        pwm.polarity = "foo"

    pwm.close()

    print("Open/close test passed.")


def test_interactive():
    print("Starting interactive test...")

    pwm = periphery.PWM(pwm_channel, pwm_pin)

    print("Starting interactive test. Get out your oscilloscope, buddy!")
    raw_input("Press enter to continue...")

    # Set initial parameters and enable PWM
    pwm.duty_cycle = 0.0
    pwm.frequency = 1e3
    pwm.polarity = "normal"
    pwm.enabled = True

    # Set 1 kHz frequency, 0.25 duty cycle
    pwm.frequency = 1e3
    pwm.duty_cycle = 0.25
    assert raw_input("Frequency is 1 kHz, duty cycle is 25%? y/n ") == "y"

    # Set 1 kHz frequency, 0.50 duty cycle
    pwm.frequency = 1e3
    pwm.duty_cycle = 0.50
    assert raw_input("Frequency is 1 kHz, duty cycle is 50%? y/n ") == "y"

    # Set 2 kHz frequency, 0.25 duty cycle
    pwm.frequency = 2e3
    pwm.duty_cycle = 0.25
    assert raw_input("Frequency is 2 kHz, duty cycle is 25%? y/n ") == "y"

    # Set 2 kHz frequency, 0.50 duty cycle
    pwm.frequency = 2e3
    pwm.duty_cycle = 0.50
    assert raw_input("Frequency is 2 kHz, duty cycle is 50%? y/n ") == "y"

    pwm.duty_cycle = 0.0
    pwm.enabled = False

    pwm.close()

    print("Interactive test passed.")


if __name__ == "__main__":
    if len(sys.argv) < 3:
        print("Usage: python -m tests.test_pwm <PMW channel> <PWM pin number>")
        print("")
        print("Hint: for BeagleBone Black, enable PWM2 (A=P8.19, B=8.13) with")
        print("    echo BB-PWM2 > /sys/devices/platform/bone_capemgr/slots")
        print("monitor P8.19, and run this test:")
        print("    python -m tests.test_pwm 0 0")
        sys.exit(1)

    pwm_channel = int(sys.argv[1])
    pwm_pin = int(sys.argv[2])

    print("Starting PMW tests...")

    test_arguments()
    test_open_close()
    test_interactive()

    print("All PWM tests passed.")