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Tests ensure LibreNMS works as expected, now and in the future. New OS should provide as much test data as needed and added test data for existing OS is welcome.

Saved snmp data can be found in tests/snmpsim/*.snmprec and saved database data can be found in tests/data/*.json. Please review this for any sensitive data before submitting. When replacing data, make sure it is modified in a consistent manner.

We utilise snmpsim to do unit testing. For OS discovery, we can mock snmpsim, but for other tests you will need it installed and functioning. We run snmpsim during our integration tests, but not by default when running lnms dev:check. You can install snmpsim with the command pip3 install snmpsim.

Capturing test data

If test data already exists

If test data already exists, but is for a different device/configuration with the same OS. Then you should use the --variant (-v) option to specify a different variant of the OS, this will be tested completely separate from other variants. If there is only one variant, please do not specify one.

1. Collect SNMP data

./scripts/collect-snmp-data.php is provided to make it easy to collect data for tests. Running collect-snmp-data.php with the --hostname (-h) allows you to capture all data used to discover and poll a device already added to LibreNMS. Make sure to re-run the script if you add additional support. Check the command-line help for more options.

2. Save test data

After you have collected snmp data, run ./scripts/save-test-data.php with the --os (-o) option to dump the post discovery and post poll database entries to json files. This step requires snmpsim, if you are having issues, the maintainers may help you generate it from the snmprec you created in the previous step.

Generally, you will only need to collect data once. After you have the data you need in the snmprec file, you can just use save-test-data.php to update the database dump (json) after that.

Running tests

Note: To run tests, ensure you have executed ./scripts/composer_wrapper.php install from your LibreNMS root directory. This will read composer.json and install any dependencies required.

After you have saved your test data, you should run lnms dev:check verify they pass.

To run the full suite of tests enable database and snmpsim reliant tests: lnms dev:check unit --db --snmpsim

Specific OS

lnms dev:check unit -o osname

Specific Module

lnms dev:check unit -m modulename

Using snmpsim for testing

You can run snmpsim to access test data by running

lnms dev:simulate

You may then run snmp queries against it using the os (and variant) as the community and as the host.

snmpget -v 2c -c ios_c3560e sysDescr.0

Snmprec format

Snmprec files are simple files that store the snmp data. The data format is simple with three columns: numeric oid, type code, and data. Here is an example snippet.|4|Pulse Secure,LLC,MAG-2600,8.0R14 (build 41869)|6|

During testing LibreNMS will use any info in the snmprec file for snmp calls. This one provides sysDescr (., 4 = Octet String) and sysObjectID (., 6 = Object Identifier), which is the minimum that should be provided for new snmprec files.

To look up the numeric OID and type of an string OID with snmptranslate:

snmptranslate -On -Td SNMPv2-MIB::sysDescr.0

List of SNMP data types:

Type Value
Integer32 2
IpAddress 64
Counter32 65
Gauge32 66
TimeTicks 67
Opaque 68
Counter64 70

Hex encoded strings (4x) should be used for any strings that contain line returns.

New discovery/poller modules

New discovery or poller modules should define database capture parameters in /tests/module_tables.yaml.

Example workflow

If the base os (.snmprec) already contains test data for the module you are testing or that data conflicts with your new data, you must use a variant to store your test data (-v).

Add initial detection

  1. Add device to LibreNMS. It is generic and device_id = 42
  2. Run ./scripts/collect-snmp-data.php -h 42, initial snmprec will be created
  3. Add initial detection for example-os
  4. Run discovery to make sure it detects properly ./discovery.php -h 42
  5. Add any additional os items like version, hardware, features, or serial.
  6. If there is additional snmp data required, run ./scripts/collect-snmp-data.php -h 42
  7. Run ./scripts/save-test-data.php -o example-os to update the dumped database data.
  8. Review data. If you modified the snmprec or code (don't modify json manually) run ./scripts/save-test-data.php -o example-os -m os
  9. Run lnms dev:check unit --db --snmpsim
  10. If the tests succeed submit a pull request

Additional module support or test data

  1. Add code to support module or support already exists.
  2. ./scripts/collect-snmp-data.php -h 42 -m <module>, this will add more data to the snmprec file
  3. Review data. If you modified the snmprec (don't modify json manually) run ./scripts/save-test-data.php -o example-os -m <module>
  4. Run lnms dev:check unit --db --snmpsim
  5. If the tests succeed submit a pull request

JSON Application Test Writing Using ./scripts/json-app-tool.php

  1. First you will need a good example JSON output produced via SNMP extend in question.
  2. Read the help via ./scripts/json-app-tool.php -h.
  3. Generate the SNMPrec data via ./scripts/json-app-tool.php -a appName -s > ./tests/snmpsim/linux_appName-v1.snmprec. If the SNMP extend name OID different than the application name, then you will need to pass the -S flag for over riding that.
  4. Generate the test JSON data via ./scripts/json-app-tool.php -a appName -t > ./tests/data/linux_appName-v1.json.
  5. Update the generated './tests/data/linux_appName-v1.json' making sure that all the expected metrics are present. This assumes that everything under .data in the JSON will be collapsed and used.

During test runs if it does not appear to be detecting the app and it has a different app name and SNMP extend name OID, make sure that -S is set properly and that 'includes/discovery/' has been updated.