1. Install using pip command
      sudo pip install jsnapy
2. Install using pip command from github
      sudo pip install git+https://github.com/Juniper/jsnapy.git 
3. Updating using pip command
      sudo pip install -U git+https://github.com/Juniper/jsnapy.git 
4. Download or clone the source code from this git repository
      git clone https://github.com/Juniper/jsnapy
   Or Untar jsnapy-master.zip (if downloaded zip folder)
      unzip jsnapy-master.zip
   Go to jsnapy-master folder and install by:
      sudo python setup.py sdist
      sudo pip install dist/jsnapy-x.x.tar.gz

# for one device, can be given like this:
    hosts:
      - device: router 
        username : abc
        passwd: pqr
    tests:
      - test_no_diff.yml 

test_command_version:
  - command: show interfaces terse lo* 
  - iterate:
      xpath: physical-interface
      id: './name'
      tests:
        - no-diff: oper-status       # element in which test is performed
          err: "Test Failed!! oper-status  got changed, before it was <{{pre['oper-status']}}>, now it is <{{post['oper-status']}}>"
          info: "Test Passed!! oper-status is same, before it is <{{pre['oper-status']}}> now it is <{{post['oper-status']}}> 

1. jsnapy --snap pre -f config_check.yml (for taking pre snapshot)
2. jsnapy --snap post -f config_check.yml (for taking post snapshot after some modification)
3. jsnapy --check pre post -f config_check.yml

(venv)sh-3.2# jsnapy --check pre post -f config_single_check.yml 
*************************Performing test on Device: 10.209.16.204*************************
Tests Included: test_command_version 
*************************Command is show interfaces terse lo**************************
----------------------Performing no-diff Test Operation----------------------
Test succeeded!! oper_status is same, before it is <['up']> now it is <['up']> 
Final result of no-diff: PASSED 
------------------------------- Final Result!! -------------------------------
Total No of tests passed: 1
Total No of tests failed: 0 
Overall Tests passed!!! 

1. config file   
   can give either:
    - full file path  
    - only file name, in this case JSNAPy will first look in present working 
      directory, if file is not present then it will take file path from "config_file_path" 
      in jsnapy.cfg file. Default config file path is "/etc/jsnapy"
2. test file: 
    - full file path  
    - only file name, in this case it will take path from "test_file_path" in jsnapy.cfg file. 
      Default test file path is "/etc/jsnapy/testfiles"
3. snap file:
    - full file path
    - tag, in this case file name is formed automatically (<devicename>_<tag>_<command/rpc>.<xml/text>)
      Snap files will be taken from "snapshot_path" in jsnapy.cfg file. 
      Default path is "/etc/jsnapy/snapshots"

jsnap2py -i test_interface.conf

jsnap2py -i test_interface.conf -o interface.yml