The Variables System in API Fortress

When an API Fortress test is executed, a variable stack is built. Every variable in the scope is accessible through API Fortress expressions and components.

The contribution to the variable stack happens in this order:

  • Global Vault
  • Project Vault
  • Test’s global variables
  • Test’s input set variables
  • Selected environment variables (also referred to as “Overrides”)
  • SET components within the test

The order is important because during the run-down if a variable is redefined, then it gets rewritten.
Say, for example, the the “domain” variable is declared in the Global Vault. Then this variable needs not to be redeclared in the other 5 stages to retain its original value.
Given the nature of these variables stores, a strategy naturally arises.

Global Vault

This is a place to store variables that live across the whole organization. Variables in this area are critical and generally stable.

Example: assume your whole organization has two domains performing two different things, and that’s all the testing you will do with API Fortress. Then two ideal domain_1 and domain_2 variables would be probably be placed here.

Project Vault

In this vault, you will store variables that serve as a common ground for all tests within a project.

Following our previous example, assuming the two services need to use two different authentication tokens, then this is the place where an auth_token variable should be stored.

Test Global

This is where you store variables that are specific to the test but are not related to a specific scenario.

For example, if you’re testing the /api/products API, then you can store the endpoint as a variable in the Test Global.

Test Input Set

This is where you store variables that are specific to a scenario.

For example, if you’re testing the /api/product/:id API, the ID is specific to a scenario, so that should be a variable in the input set. The ability to have multiple input sets in a set allows you to run a test against multiple scenarios.

Environment / Overrides

An environment (or override) is a set of variables that represent a temporary change in the premises of a test.

For example if, as a default, the domain variable reflects a production environment, but you occasionally want to run the test against a staging environment, this is where you redefine the variable. Being “environment” the last step prior to test execution, it will win over the default.

Note:
 as a general rule of thumb, we strongly advocate for not relying on environments for the test to function properly. Tests should be self-sufficient and already be able to run before the environment stage, which should be used to change the value to certain variables, not defining new ones.
 

SET Component

Finally, the SET component allows you to create variables during test execution. This is useful when a certain variable acquires a value based on what happens during the test, such as a key in a payload, or a computed value.