How to: Use actions and guards#

Actions and Guards provide a way to split the test based on the data which you use. That approach allows you to reuse/combine/change the data for each test separately. It lets you to test login with different credentials, or iteration through boundary values and equivalent classes.

Overview#

GraphWalker keeps a context for each model plus a global context. A context is a set of variables.

GraphWalker has two way to interact with the data from the context:

  1. Actions allow you to initialize and update the data from the context.

  2. Guard allows you to block (guard) edges until a condition is met.

Each model has a unique set of variables, so if you want to use variables across models you must save them in the global context. Every variable of the form global.<variable-name> is saved in the global context (e.g. global.count, global.isLoggedIn).

Note

Throughout the documentation the data from the context is usually referred as graph data or just data.

Actions#

An action is a piece of JavaScript code executed by GraphWalker. You can place action on the model level which will be executed before any step from that model or on an edge which will be executed when an edge is reached.

Examples:

{
    "actions": [
        "global.count++;",
        "isUserLoggedIn = false;"
    ]
}

Note

Each action must end with ; (e.g. count++; is a valid action while count++ is not).

Guards#

A guard is a piece of JavaScript code which if evaluates as false marks an edge as unreachable, the guard can use the variables from the context of the current model of the global context.

Examples:

{
    "guard": "isUserLoggedIn == false",
}

{
    "guard": "global.count > 10",
}

Log In Example#

Let’s consider the model below which has a login test (v_logged_in) and a logout test (v_logged_out). Note that the two vertices could reference another models with the rest of the functionality, for logged in users respectively logged out users, but for the simplicity of the example we are using only two vertices.

Model visualization:

../_images/login-model.png

Screenshot taken from the Model-Editor.#

Model source:

{
    "name": "Simple login example",
    "models": [
        {
            "name": "LoginModel",
            "generator": "random(vertex_coverage(100))",
            "startElementId": "v_0",
            "actions": [
                "isUserLoggedIn = false;"
            ],
            "vertices": [
                {
                    "id": "v_0",
                    "name": "v_start"
                },
                {
                    "id": "v_1",
                    "name": "v_app"
                },
                {
                    "id": "v_2",
                    "name": "v_logged_in"
                },
                {
                    "id": "v_3",
                    "name": "v_logged_out"
                }
            ],
            "edges": [
                {
                    "id": "e_0",
                    "name": "e_open_app",
                    "sourceVertexId": "v_0",
                    "targetVertexId": "v_1"
                },
                {
                    "id": "e_1",
                    "name": "e_log_in",
                    "guard": "isUserLoggedIn == false",
                    "actions": [
                        "isUserLoggedIn = true;"
                    ],
                    "sourceVertexId": "v_1",
                    "targetVertexId": "v_1"
                },
                {
                    "id": "e_2",
                    "name": "e_log_out",
                    "guard": "isUserLoggedIn == true",
                    "actions": [
                        "isUserLoggedIn = false;"
                    ],
                    "sourceVertexId": "v_1",
                    "targetVertexId": "v_1"
                },
                {
                    "id": "e_3",
                    "name": "e_for_user_logged_in",
                    "guard": "isUserLoggedIn == true",
                    "sourceVertexId": "v_1",
                    "targetVertexId": "v_2"
                },
                {
                    "id": "e_4",
                    "name": "e_for_user_not_logged_in",
                    "guard": "isUserLoggedIn == false",
                    "sourceVertexId": "v_1",
                    "targetVertexId": "v_3"
                }
            ]
        }
    ]
}

The idea is that:

  • At first isUserLoggedIn is set to false by the models actions.

  • Go on v_start which is the starting point.

  • Go on e_open_app and launch the application.

  • Now we are on the v_app vertex.

And from here there are two paths:

  1. Not Logged In Path:

  • Now we can go on e_for_user_not_logged_in edge for which the guard condition (isUserLoggedIn == false) is met.

  • Now we are on v_logded_out where we have some test which don’t need a logged in user.

  1. Logged In Path:

  • Go on the e_log_in edge, witch will set isUserLoggedIn to true.

  • Now we can go on e_for_user_logged_in edge because the guard condition (isUserLoggedIn == true) is met.

  • Now we are on v_logded_in where we have some test for a logged in user.

And, by the way…

You can download the model: login.json.

And use the init command to generate a project from the model (for python or c#):

altwalker init action-example -m login.json -l python

altwalker init action-example -m login.json -l c#

And then you can run the example.

If you need help with the init command check out the Quickstart section.