Stack-Level Testing

Stack-level testing refers to testing specific stacks. Their tests live within the stack’s folder itself and are meant to be ran independently.

Structure

Let’s say you have terraform stack named demo:

app/stacks/demo
├── main.tf
├── outputs.tf
└── variables.tf

We can use terraspace new test run from the root of the terraspace project to create a app/stacks/demo/test/spec/main_spec.rb test.

terraspace new test demo --type stack

The structure will look something like this:

app/stacks/demo/test
└── spec
    ├── fixtures
    │   └── stack
    │       ├── main.tf
    │       └── outputs.tf
    └── main_spec.rb

Test Code

Here’s an example of the generate spec.

app/stacks/demo/test/spec/main_spec.rb:

describe "main" do
  before(:all) do
    stack_path = File.expand_path("../..", __dir__) # the source of the stack to test is 2 levels up
    ts_root = File.expand_path("../../..", stack_path) # original Terraspace.root
    # Build terraspace project to use as a test harness
    # Will be located at: /tmp/terraspace/test-harnesses/demo-harness
    terraspace.build_test_harness(
      name:    "demo-harness",
      modules: "#{ts_root}/app/modules", # include all modules in folder
      stacks:  {demo: stack_path},
      # override demo stack tfvars for testing
      tfvars:  {demo: "#{stack_path}/spec/fixtures/tfvars/demo.tfvars"},
      # create config if needed. The folder will be copied over
      # config:  "#{stack_path}/spec/fixtures/config",
    )
    terraspace.up("demo")
  end
  after(:all) do
    terraspace.down("demo")
  end

  it "successful deploy" do
    # Replace with your own test
    expect(true).to be true
    # Example
    # pp terraspace.outputs
    # output_value = terraspace.output("demo", "some-output")
    # expect(output_value).to include("some-value")
    # More useful helpers:
    # pp terraspace.state['resources']
    # pp terraspace.state_resource('random_pet.this')
    # pp terraspace.state_resource('module.bucket')
  end
end

Run Tests

To run the test, you should be within in the module folder itself.

cd app/stacks/demo
bundle
terraspace test

The test process will:

  1. Generate a test harness, which is a terraspace project
  2. Run terraspace up to create actual resources
  3. Run your test logic
  4. Run terraspace down to destroy the resources

In this section:

    More tools: