How infra-tester Works Internally

infra-tester uses terratest internally to run Terraform tests. Once infra-tester parses the test configuration, for each test:

1. If at least one plan assertion is found, it'll run terraform plan with the input variables if defined.
2. It then runs all the assertions under the plan step.
3. If any of the plan step assertions fails, it skips the apply assertions for the test. This can be considered a "fail fast" mechanism to prevent unnecessary cost and time wastage when the plan tests have failed.
4. If all the plan assertions were successful, it then proceeds to apply assertions.
5. infra-tester runs terraform plan with the input variables if defined. Note that a destroy won't be called before running the apply unless with_clean_state is set to true. This is for efficiency reasons, see test_plan.tests.with_clean_state.
6. Once all the tests are run, infra-tester proceeds to destroy all resources as a final cleanup procedure.

%%{init: {'theme':'neutral'}}%%

flowchart TB
  subgraph TestPlan[<b>Test Plan</b>]
    direction TB
    subgraph Test1[<b>Test 1</b>]
        direction LR
        Plan1(Plan\nResource\nCreation) --> AssertP1(Plan\nAssertions\n1..N<sub>1</sub>) --> Create1(Resource\nCreation) --> Assert1(Assertions\n1..M<sub>1</sub>)
    end
    subgraph Test2[<b>Test 2</b>]
        direction LR
        Plan2(Plan\nResource\nModification) --> AssertP2(Plan\nAssertions\n1..N<sub>2</sub>) --> Create2(Resource\nModification) --> Assert2(Assertions\n1..M<sub>2</sub>)
    end
    subgraph TestN[<b>Test N</b>]
        direction LR
        PlanN(Plan\nResource\nModification) --> AssertPN(Plan\nAssertions\n1..N<sub>k</sub>) --> CreateN(Resource\nModification) --> AssertN(Assertions\n1..M<sub>k</sub>)
    end
    Test1 --> Test2
    Test2 --> dots((...))
    dots((...)) --> TestN
  end
Start:::term --> Test1
TestN --> destroy(Destroy\nResources) --> End:::term