AUTOMATED TESTING USING PYTHON (ATE)

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YUVARAJA.R - M.TECH EMBEDDED SYSTEMS TECHNOLOGIES
REG NO - 13PEES1005
PROJECT INCHARGE - K.Bhaskar.,B.Tech.,M.E.(Ph.D)
COLLEGE - VEL TECH Dr.RR & Dr.SR TECHNICAL UNIVERSITY
AUTOMATED HARDWARE TESTING
USING PYTHON

ABSTRACT
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Design a Embedded Prototype test hardware
interact with Python software shows presence of
defects in UUT. Python test script can download
the test cases to the target system one by one,
receive test output, compare with specifications
then verify it, and generate log files. Log files inside
test steps results are stored as PASS/FAIL.
It’s a cost effective test system for SS Electronic
hardware manufacturers

TESTING
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Testing is an organized process to verify the
behavior, performance, and reliability of a device
It ensures a device or system to be as defect-free as
possible
Testing is a manufacturing step to ensure that the
manufactured device is defect free.
Manual Testing
Automated Testing

Manual & Automated Testing
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Testing is carried out manually by test engineers.
Consuming a lot of time and effort huge for spending the
time for manual testing.
Automated test equipment need a special fixture to place
the board and test the device using instruments

EXISTING SYSTEM
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Testing is carried out manually by test engineers.
Consuming a lot of time and effort huge for spending the
time for testing.
NI Lab View designing a ATE .But measurements are taken
by reputed instruments or NI PXI only
PXI HW and its software is huge amount.
Certified engineer only able to access the software
Add-on software needed for Test case and Report
generation .

PROPOSED SYSTEM
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 To overcome the existing problem, we construct
Embedded hardware test module to measure the
 Resistance test applied to signal traces (short/open)
 Voltage /current measure with help of analog pins.
 IO pins used to trigger the on/off or control the hw.
 Protocols testing are done by the test hardware.
Tested data packets serially communicated to the
Python scripts
 Python scripts collect the complied data's then
compare with test case input and generate the test
reports..

PROJECT – ENTIRE SYSTEM
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SERIAL INTERFACE

EMBEDDED TEST HW DESIGN
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Atmega 8-bit AVR controller used for Embedded Test
Hardware system.
Necessity to test the every protocols chips, Analog and
Digital IC.
Current, Voltage and Resistance measurements using
10bit ADC
I2C >> | RTC | EEPROM | SENSORS | DEVICES |
UART >> RS232 <<
RS485 >> 75176-IC <<
RS422 >> 75176 TX+ ->>75176 RX+ -<<

PYTHON
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Python is a clear and powerful object-oriented
programming language, comparable to Perl,
Tcl and Java.
It’s a FOSS Programming language.
Runs on many different computers and
operating systems: Windows, MacOS, many
brands of Unix, OS/2
Python Code can be grouped into modules and
packages

HW DESIGN – VOLTAGE ,CURRENT &
RESISTANCE MEASUREMENT
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Voltage measured by using AVR Controller 10bit
ADC .
Constant current probing to the voltage net through
voltage divider circuit. Impedance measured by the
ADC.
Current measurement taken by ACS712 Current
sensor IC.

CURRENT MEASURMENT USING ACS712
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Hall-effect sensor ICs (especially the ratio metric
linear types) are superb devices for 'open-loop'
current-sensing designs

HW DESIGN – PROTOCOLS TESTING-I2C
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I2C (Inter-Integrated Circuit, pronounced "I squared C") is
also a synchronous protocol.I2C uses only 2 wires, one for
the clock (SCL) and one for the data (SDA). That means
that master and slave send data over the same wire, again
controlled by the master.

I2C PROTOCOLS TESTING –SCANNER
METHOD
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Sequence of 7-bit address send to the slave device .
Wire.beginTransmission(address);
ack = Wire.endTransmission();
ACK=‘0’ device found.
>I2C Device found at adress 0x48,0x57,0x67
>[3 device found ]

HW DESIGN – PROTOCOLS TESTING-
UART / RS232 SERIAL
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 Serial communication is the process of sending
data one bit one by one sequentially, over a
communication channel.
UART communication of Full duplex TX and RX
communication through the COM devices.

HW DESIGN – PROTOCOLS TESTING – RS422
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 The RS422 Standard defines a serial communications standard.
RS422 is a high speed and long distance data transmission. Each signal
is carried by a pair of wires and is thus a differential data transmission
system.

HW DESIGN – PROTOCOLS TESTING – RS485
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 RS-485 is a superset of RS-422; thus, all RS-422 devices
may be controlled by RS-485. RS-485 hardware may be
used for serial communication with up to 4000 feet of
cable.
The main difference is that up to 32 transmitter receiver
pairs may be present on the line at one time. RS485
Differential communication A <-> B Signal lines.

SOFTWARE DESIGN - PYTHON
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An open source software used to Automate the
Hardware Testing
UNITTEST module supports test automation,
sharing of setup and shutdown code for tests,
aggregation of tests into collections, and
independence of the tests from the reporting
framework.
PySerial module supports serial communication
between device to pc data transmission.
File handling function used to generate the log
file report.

UNIT TEST MODULE CONCEPTS
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 Test Fixture : It represents the preparation needed to
perform one or more tests, and any associate cleanup
actions. This may involve, for example, creating temporary
or proxy databases, directories, or starting a server
process.
 Test Case: is the smallest unit of testing. It checks for a
specific response to a particular set of inputs. Unit test
provides a base class, Test Case which may be used to
create new test cases.
 Test Suite: Test suite is a collection of test cases, test
suites, or both. It is used to aggregate tests that should be
executed together.

REQUIREMENTS & TEST CASE
RELATIONSHIP
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UUT CODE SAMPLE
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Def ScaledInput(data):
rc = NO_ERR
scaled_data = data
if data >= DATA_MIN and data <= DATA_MAX:
scaled_data = (data * data_scale) + data_offset
if scaled_data > SCALE_MAX:
scaled_data = SCALE_MAX
rc = ERR_MAXSCALE
elif scaled_data < SCALE_MIN:
scaled_data = SCALE_MIN
rc = ERR_MINSCALE
else:
rc = ERR_OVER
return (rc, scaled_data)
Function code getting one input argument
Function Returning two o/p values

Function with argument code table
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A unit test is constructed such that all possible inputs are
used to force the execution to traverse all possible paths. In
the case of ScaledInput(), we can see that there are three
obvious input test cases. Too low,
Too high,
Within range.

PYSERIAL MODULE
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This module encapsulates the access for the serial
port. The module named “serial” automatically
selects the appropriate backend
Same class based interface on all supported
platforms.
Access to the port settings through Python
properties.
Support for different byte sizes, stop bits, parity and
flow control with RTS/CTS and/or Xon/Xoff.
Working with or without receive timeout.

PY SERIAL COM PORT CODE
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class AHT_Serial(object):
def __init__(self, serial_port='COM3',
baud_rate=9600,read_timeout=5):
self.serial = serial.Serial(serial_port, baud_rate)
self.serial.timeout = read_timeout
def read_line(self):
"""Reads the serial buffer"""
return self.serial.readline()
Rxvalue=AHT_Serial.readline()

FILE HANDLING IN PYTHON
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Python generally divide files into two categories, text file
and binary file. Text files are simple text where as the
binary files contain binary data which is only readable by
computer.
File opening
To open a file we use open() function. It requires two
arguments, first the file path or file name, second which
mode it should open. Modes are like
“r” -> open read only,
“w” -> open with write power, means if the file exists
then delete all content and open it to write
“a” -> open in append mode

LOG FILE GENERATION CODE
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class fileHand(object):
tMess=""
curTime=[]
def fileWrite(self,varlnk):
lp=0
tMess=""
varlnk=list(varlnk)
selfvarcall=fileHand()
tm=selfvarcall.write_dummy()
for lp in varlnk:
print(lp)
tMess+=time.ctime()+" >> "+ "Voltage test{}n".format(lp)
fileOpen = open('LogfileV1.2.txt','w',encoding='utf-8',errors='ignore')
fileOpen.write("########## AHT LOG FILE ############"'n')
fileOpen.close()
return 'writed'

TEST RESULT REPORT
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############################ AHT LOG FILE ############################
Wed Apr 27 10:16:52 2016 >> Testing Started....
Wed Apr 27 10:16:52 2016 >> Tester Initialization done..
Wed Apr 27 10:16:52 2016 >> TH Version 1.0
Wed Apr 27 10:16:52 2016 >> Test Sequence Started -> || PS UNIT || I2C Protocols ||
Wed Apr 27 10:16:52 2016 >> Test Case Loaded Successfully
##########################################################################
Wed Apr 27 10:16:52 2016 >> Voltage test 3.3V => 3.25V =>Pass
Wed Apr 27 10:16:53 2016 >> Voltage test 5v => 4.85V =>Pass
Wed Apr 27 10:16:53 2016 >> Resistance test 3.3V => 120E =>Pass
Wed Apr 27 10:16:54 2016 >> Resistance test 5V => 0E =>Fail
Wed Apr 27 10:16:54 2016 >> Current Test 3.3V => .55A =>Pass
Wed Apr 27 10:16:55 2016 >> Current Test 5V => .85A =>Pass
Wed Apr 27 10:16:56 2016 >> I2C Test Device Found=> 0x30,0x48,0x54 =>Pass
Wed Apr 27 10:16:56 2016 >> RTC INC Test => - =>Pass
Wed Apr 27 10:16:57 2016 >> Temp Test =>29.1c =>Pass
Wed Apr 27 10:16:58 2016 >> EEPROM Test => - =>Pass
Wed Apr 27 10:16:58 2016 >> RS232 Test => ABCD =>Pass
Wed Apr 27 10:16:58 2016 >> RS422- RS485 => ABCD =>Pass
###########################################################################
Wed Apr 27 10:16:59 2016 >> Test Sequence Stopped >>FAIL

ADVANTAGES
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Boards, components and interface cable separately
tested in modes of test case.
Manual testing has been reduced
Locating the Hardware(components) and software
bugs using test reports.
Low Cost (Pursuing software’s are Open source)
Reduced human efforts

DISADVANTAGES
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Embedded controllers are single task at a instant.
So measuring data goes to the pc with delay. Output
data packets compared with test case help of
Python Script. So report generating time taken
more.

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Automatic hardware testing using Python is a ATE
technique to increase throughput without a
corresponding increase in cost, by performing tests on
protocols are handling and test without error. It has been
quantitatively to reduce test cost more effectively than
low-cost ATE. Because it reduces all test cost
contributors, and not only capital cost of ATE.
 In this paper, we described the AHT using python
strategy adopted for hardware testing and protocols
testing without measuring instruments .
CONCULSION

FUTURE ENHANCEMENT
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In this project in future we can add a FPGA or CPLD
used to get the data packets at instant of time
without delay.
Parallel Testing method introduces to test the
multiple boards at same instant time.

BASE PAPERS
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 [1] Jambunatha, K .,Design and implement Automated Procedure to upgrade remote
network devices using Python, Advance Computing Conference (IACC), 2015 IEEE
International, Bangalore, June 2015.
 [2] H.J. Zainzinger and S.A. Austria, "Testing embedded systems by using C++ script
interpreter," in Proceedings of the 11 th Asian Test Symposium(ATS’02), 2002, pp.380 –
385
 [3] Kovacevic, M.; Kovacevic, B.; Pekovic, V.; Stefanovic, D., Framework for automatic
testing of Set-top boxes., Telecommunications Forum Telfor (TELFOR), 22ndYear: 2014
 [4] Karmore, S.P.; Mabajan, A.R., Universal methodology for embedded system testing.,
Computer Science & Education (ICCSE), 2013 8th International Conference on Year:
2013,IEEE Conference Publications, 26-28 April 2013
 [5] Kim H. Pries, Jon M. Quigley-Testing Complex and Embedded Systems-CRC Press
(2010)
 [6] Python software Foundation https://www.python.org/

INTERNATIONAL CONFERENCE
CERTIFICATE
32

AUTOMATED TESTING USING PYTHON (ATE)

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