Picture this: It’s 1 AM. I am not even joking:
You’ve just refactored your Terraform module to add the auto-scaling magic. You merge. You deploy. You go to bed. The next morning? Production is literally on fire 🔥 because your “tiny” change accidentally nuked the database.
How to stop “Oops” from becoming “OH NO” …
Test-Driven Chaos Prevention 🧪
Terraform tests (available in v1.6+) let you validate config changes before they touch your infrastructure. Think of them as your code’s personal bouncer, checking IDs at the door.
# valid_string_concat.tftest.hcl
run "did_i_break_everything" {
command = plan
assert {
condition = aws_s3_bucket.bucket.name == "my-glittery-unicorn-bucket"
error_message = "Name mismatch! Abort mission! 🚨"
}
}
Translation: “If the bucket name isn’t ‘my-glittery-unicorn-bucket,’ error and abort.”
How Terraform Tests Save You 🤗
1️⃣ command = plan: Simulate changes without touching real infra. “What if…?” but for adults.
2️⃣ Assertions: Like a clingy ex, they’ll text you 100x if something’s wrong. Example:
assert {
condition = output.bucket_name == "test-bucket"
error_message = "This is NOT the bucket you’re looking for. 👋"
}
3️⃣ Variables & Overrides: Test edge cases without redeploying. Example: “What if someone sets bucket_prefix to 🔥?”
Some Tips !
- Mock Providers (v1.7+): Fake it ’til you make it. Test AWS without paying AWS 👍
- Expect Failure: Want to validate that a config should break? Use
expect_failures. Example:
run "expect_chaos" {
variables { input = 1 } # Odd number → should fail validation
expect_failures = [var.input]
}
Translation: “If this doesn’t fail, I’ve lost faith in humanity.” (I have already tbh)
- Modules in Tests: Reuse setup/teardown logic like a lazy genius. Example: A “test” module that pre-creates a VPC so you can focus on actual work.
module "consul" {
source = "hashicorp/consul/aws"
version = "0.0.5"
servers = 3
}The Takeaway 🚀
Testing is like adding seat belts to your code: boring until you crash !
Use run blocks, assertions, and provider mocking to:
- Avoid “Works on My Machine” syndrome
- Sleep better (no 3 AM “WHY IS S3 DOWN”)
- Brag in PR reviews (“My tests caught 10 bugs. Your move, Karen.”)
TL;DR: Write tests. Save your sanity.
Resources:
[1] https://www.paloaltonetworks.com/blog/prisma-cloud/hashicorp-terraform-cloud-run-tasks-integration
[2] https://developer.hashicorp.com/terraform/language/tests
Rafaela Azevedo 