CIT Varianter Plugin

This plugin is an implementation of a “Combinatorial Interaction Testing with Constraints” algorithm for the Avocado varianter functionality. It generates an optimal number of variants, which in turn become different test scenarios. To learn more about this algorithm, please take a look to the papers listed below.

To run the example below, use the test included in the avocado code

$ git clone

Please refer to avocado/examples/varianter_cit/params.cit for an example of a input file.

Input file format

The following is the general structure of a input file:

Parameter_1 [Value_1,  Value_2, Value_3, Value_4]
Parameter_2 [Value_1,  Value_2, Value_3, Value_4]
Parameter_3 [Value_1,  Value_2, Value_3, Value_4]

Parameter_1 != Value_1 || Parameter_2 != Value_3
Parameter_3 != Value_2 || Parameter_2 != Value_4 || Parameter_1 != Value_4

The input file has two parts, parameters and constraints.


  • Each line represent one parameter.
  • Each parameter has a name, and a list of values ​​inside brackets.


  • Constraints have to be in Conjunctive normal form.

  • Constraints use these tree operands: !=, OR, AND

  • || represents operand OR and new line represents operand AND.

  • In the example, this is the logic formula

    ((P_1 != V1 OR P_2 != V_3) AND (P_3 != V_2 OR P_2 != V_4 OR P_1 != Value_4))



the algorithm employed here can be CPU intensive. If you want more information on the progress of the combinatorial calculation, add --debug to a command line, such as avocado variants --debug --cit-parameter-file $PATH

Cit varianter plugin runs with two parameters:

  • --cit-parameter-file with path to the input file
  • --cit-order-of-combinations with strength of combination (default is 2)

To see the variants generated by this demo implementation, execute:

$ avocado variants --cit-parameter-file avocado/examples/varianter_cit/params.cit
CIT Variants (28):
Variant red-square-solid-plastic-anodic-6-4-4-2:    /
Variant green-circle-gas-leather-cathodic-7-5-4-1:    /
Variant green-triangle-liquid-leather-anodic-5-4-1-3:    /
Variant green-square-liquid-plastic-anodic-3-1-4-5:    /
Variant red-triangle-solid-leather-anodic-5-2-4-1:    /
Variant black-triangle-gas-leather-anodic-7-1-1-2:    /
Variant green-circle-solid-aluminum-cathodic-7-1-5-4:    /
Variant red-square-gas-plastic-cathodic-6-3-5-3:    /
Variant gold-triangle-solid-leather-anodic-6-5-1-4:    /
Variant gold-triangle-gas-leather-anodic-3-2-5-2:    /
Variant gold-square-gas-plastic-cathodic-5-1-1-1:    /
Variant red-circle-gas-plastic-anodic-1-1-3-3:    /
Variant red-circle-gas-aluminum-cathodic-3-3-1-5:    /
Variant black-triangle-solid-plastic-cathodic-5-5-5-5:    /
Variant gold-triangle-gas-leather-anodic-7-4-2-5:    /
Variant black-triangle-gas-aluminum-cathodic-6-1-2-1:    /
Variant gold-square-liquid-leather-cathodic-3-5-2-3:    /
Variant black-square-solid-aluminum-cathodic-7-2-4-3:    /
Variant black-circle-liquid-aluminum-anodic-1-4-5-1:    /
Variant black-triangle-gas-leather-cathodic-7-3-3-1:    /
Variant green-square-solid-aluminum-cathodic-1-3-2-2:    /
Variant gold-triangle-gas-aluminum-anodic-1-3-4-4:    /
Variant red-square-liquid-plastic-anodic-7-2-2-4:    /
Variant gold-circle-liquid-aluminum-anodic-5-5-3-2:    /
Variant red-triangle-gas-leather-anodic-1-5-1-5:    /
Variant gold-circle-liquid-aluminum-cathodic-5-3-2-4:    /
Variant black-square-solid-plastic-cathodic-3-4-3-4:    /
Variant green-circle-liquid-plastic-cathodic-6-2-3-5:    /


The exact variants generated are not guaranteed to be the same across executions.

You can enable more verbosity, making each variant to show its content:

$ avocado variants --cit-parameter-file avocado/examples/varianter_cit/params.cit -c
CIT Variants (28):

Variant red-circle-solid-plastic-cathodic-6-3-3-1:    /
    /:coating  => cathodic
    /:color    => red
    /:material => plastic
    /:p10      => 1
    /:p7       => 6
    /:p8       => 3
    /:p9       => 3
    /:shape    => circle
    /:state    => solid

Variant black-circle-liquid-aluminum-anodic-6-5-1-2:    /
    /:coating  => anodic
    /:color    => black
    /:material => aluminum
    /:p10      => 2
    /:p7       => 6
    /:p8       => 5
    /:p9       => 1
    /:shape    => circle
    /:state    => liquid

... Skip 26 more variants ...

To execute tests with those combinations use:

$ avocado run avocado/examples/tests/ --cit-parameter-file avocado/examples/varianter_cit/params.cit
JOB ID     : 6abd9e9f1ff9ed33a353ca8f3ef845cd4cc404a5
JOB LOG    : $HOME/avocado/job-results/job-2018-07-23T08.46-6abd9e9/job.log
 (01/25);black-circle-gas-plastic-anodic-3-3-5-5: PASS (0.04 s)
 (02/25);gold-square-liquid-leather-anodic-3-2-1-4: PASS (0.03 s)
 (03/25);green-square-gas-plastic-cathodic-3-5-4-1: PASS (0.04 s)
 (04/25);gold-circle-solid-leather-anodic-6-4-4-2: PASS (0.04 s)
 (05/25);green-triangle-liquid-aluminum-cathodic-7-4-5-1: PASS (0.04 s)
 (06/25);black-circle-gas-plastic-cathodic-1-4-3-4: PASS (0.04 s)
 (07/25);red-square-gas-leather-anodic-3-4-2-3: PASS (0.04 s)
 (08/25);gold-triangle-solid-leather-anodic-1-3-2-1: PASS (0.04 s)
 (09/25);green-circle-gas-plastic-cathodic-7-1-2-4: PASS (0.04 s)
 (10/25);green-triangle-gas-aluminum-cathodic-6-2-2-5: PASS (0.04 s)
 (11/25);black-circle-liquid-plastic-cathodic-5-5-2-2: PASS (0.03 s)
 (12/25);red-square-solid-aluminum-anodic-5-2-3-1: PASS (0.04 s)
 (13/25);gold-square-solid-leather-anodic-7-5-3-5: PASS (0.04 s)
 (14/25);green-triangle-solid-leather-anodic-1-5-1-3: PASS (0.04 s)
 (15/25);black-circle-liquid-leather-cathodic-6-1-1-1: PASS (0.04 s)
 (16/25);red-triangle-liquid-plastic-anodic-6-3-3-3: PASS (0.04 s)
 (17/25);green-triangle-solid-plastic-cathodic-5-3-4-4: PASS (0.04 s)
 (18/25);red-square-liquid-aluminum-anodic-6-5-5-4: PASS (0.04 s)
 (19/25);red-square-gas-aluminum-cathodic-7-3-1-2: PASS (0.04 s)
 (20/25);red-square-liquid-aluminum-anodic-1-1-4-5: PASS (0.04 s)
 (21/25);gold-circle-gas-plastic-anodic-5-4-1-5: PASS (0.04 s)
 (22/25);gold-circle-solid-leather-anodic-5-1-5-3: PASS (0.04 s)
 (23/25);red-circle-liquid-plastic-cathodic-1-2-5-2: PASS (0.04 s)
 (24/25);green-triangle-solid-aluminum-anodic-3-1-3-2: PASS (0.04 s)
 (25/25);black-circle-solid-aluminum-cathodic-7-2-4-3: PASS (0.03 s)
JOB TIME   : 1.21 s
JOB HTML   : $HOME/avocado/job-results/job-2018-07-23T08.46-6abd9e9/results.html


The publication by Ahmed, Bestoun S., Kamal Z. Zamli, and Chee Peng Lim, entitled “Application of particle swarm optimization to uniform and variable strength covering array construction”, Applied Soft Computing, 12(4), 2012, pp. 1330-1347, contains the basis for the algorithm and implementation of this feature.

Additionally, the publication by Bestoun S. Ahmed, Amador Pahim, Cleber R. Rosa Junior, D. Richard Kuhn and Miroslav Bures, entitled “Towards an Automated Unified Framework to Run Applications for Combinatorial Interaction Testing”, contain a practical use case of this software.