Convert to go modules, further enhance tests

examples/complete/fixtures.us-east-2.tfvars

@@ -1 +1,10 @@
-example = "Hello, world!"
+region = "us-east-2"
+
+namespace = "eg"
+
+environment = "ue2"
+
+stage = "test"
+
+name = "example"
+

examples/complete/outputs.tf

@@ -1,3 +1,8 @@
+output "id" {
+  description = "ID of the created example"
+  value = module.example.id
+}
+
 output "example" {
   description = "Output \"example\" from example module"
   value       = module.example.example

outputs.tf

@@ -1,3 +1,8 @@
+output "id" {
+  description = "ID of the created example"
+  value = module.this.enabled ? module.this.id : null
+}
+
 output "example" {
   description = "Example output"
   value       = module.this.enabled ? local.example : null

test/src/Makefile

@@ -1,50 +1,30 @@
-PACKAGE  = terraform-aws-ecs-container-definition
-GOEXE   ?= /usr/bin/go
-GOPATH   = $(CURDIR)/.gopath
-GOBIN    = $(GOPATH)/bin
-BASE     = $(GOPATH)/src/$(PACKAGE)
-PATH 	:= $(PATH):$(GOBIN)
-
-export TF_DATA_DIR ?= $(CURDIR)/.terraform
 export TF_CLI_ARGS_init ?= -get-plugins=true
-export GOPATH
+export TERRAFORM_VERSION ?= $(shell curl -s https://checkpoint-api.hashicorp.com/v1/check/terraform | jq -r -M '.current_version' | cut -d. -f1-2)
 
+.DEFAULT_GOAL : all
 .PHONY: all
+
 ## Default target
 all: test
 
-ifneq (,$(wildcard /sbin/apk))
-## Install go, if not installed
-$(GOEXE):
-	apk add --update go
-endif
-
-ifneq ($(findstring $(shell uname -s),Linux Darwin),)
-## Install all `dep`, if not installed
-$(GOBIN)/dep:
-	@mkdir -p $(GOBIN)
-	@curl https://raw.githubusercontent.com/golang/dep/master/install.sh | sh
-endif
-
-## Prepare the GOPATH
-$(BASE): $(GOEXE)
-	@mkdir -p $(dir $@)
-	@ln -sf $(CURDIR) $@
-
-## Download vendor dependencies to vendor/
-$(BASE)/vendor: $(BASE) $(GOBIN)/dep
-	cd $(BASE) && dep ensure
-
 .PHONY : init
 ## Initialize tests
-init: $(BASE)/vendor
+init:
+	@exit 0
 
 .PHONY : test
 ## Run tests
 test: init
-	cd $(BASE) && go test -v -timeout 30m -run TestExamplesComplete
+	go mod download
+	go test -v -timeout 60m -run TestExamplesComplete
+
+## Run tests in docker container
+docker/test:
+	docker run --name terratest --rm -it -e AWS_ACCESS_KEY_ID -e AWS_SECRET_ACCESS_KEY -e AWS_SESSION_TOKEN -e GITHUB_TOKEN \
+		-e PATH="/usr/local/terraform/$(TERRAFORM_VERSION)/bin:/go/bin:/usr/local/go/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin" \
+		-v $(CURDIR)/../../:/module/ cloudposse/test-harness:latest -C /module/test/src test
 
 .PHONY : clean
 ## Clean up files
 clean:
-	rm -rf .gopath/ vendor/ $(TF_DATA_DIR)
+	rm -rf ../../examples/complete/*.tfstate*

test/src/examples_complete_test.go

@@ -1,32 +1,81 @@
 package test
 
 import (
+	"math/rand"
+	"strconv"
+	"testing"
+
 	"github.com/gruntwork-io/terratest/modules/terraform"
 	"github.com/stretchr/testify/assert"
-	"testing"
 )
 
 // Test the Terraform module in examples/complete using Terratest.
 func TestExamplesComplete(t *testing.T) {
 	t.Parallel()
 
+	randId := strconv.Itoa(rand.Intn(100000))
+	attributes := []string{randId}
+
+	exampleInput := "Hello, world!"
+
 	terraformOptions := &terraform.Options{
 		// The path to where our Terraform code is located
 		TerraformDir: "../../examples/complete",
 		Upgrade:      true,
 		// Variables to pass to our Terraform code using -var-file options
 		VarFiles: []string{"fixtures.us-east-2.tfvars"},
+		// We always include a random attribute so that parallel tests
+		// and AWS resources do not interfere with each other
+		Vars: map[string]interface{}{
+			"attributes": attributes,
+			"example":    exampleInput,
+		},
 	}
-
 	// At the end of the test, run `terraform destroy` to clean up any resources that were created
 	defer terraform.Destroy(t, terraformOptions)
 
 	// This will run `terraform init` and `terraform apply` and fail the test if there are any errors
 	terraform.InitAndApply(t, terraformOptions)
 
 	// Run `terraform output` to get the value of an output variable
-	outputExample := terraform.Output(t, terraformOptions, "example")
+	id := terraform.Output(t, terraformOptions, "id")
+	example := terraform.Output(t, terraformOptions, "example")
+	random := terraform.Output(t, terraformOptions, "random")
 
 	// Verify we're getting back the outputs we expect
-	assert.Regexp(t, "^Hello world! [0-9]+$", outputExample)
+	// Ensure we get a random number appended
+	assert.Equal(t, exampleInput+" "+random, example)
+	// Ensure we get the attribute included in the ID
+	assert.Equal(t, "eg-ue2-test-example-"+randId, id)
+
+	// ************************************************************************
+	// This steps below are unusual, not generally part of the testing
+	// but included here as an example of testing this specific module.
+	// This module has a random number that is supposed to change
+	// only when the example changes. So we run it again to ensure
+	// it does not change.
+
+	// This will run `terraform apply` a second time and fail the test if there are any errors
+	terraform.Apply(t, terraformOptions)
+
+	id2 := terraform.Output(t, terraformOptions, "id")
+	example2 := terraform.Output(t, terraformOptions, "example")
+	random2 := terraform.Output(t, terraformOptions, "random")
+
+	assert.Equal(t, id, id2, "Expected `id` to be stable")
+	assert.Equal(t, example, example2, "Expected `example` to be stable")
+	assert.Equal(t, random, random2, "Expected `random` to be stable")
+
+	// Then we run change the example and run it a third time and
+	// verify that the random number changed
+	newExample := "Goodbye"
+	terraformOptions.Vars["example"] = newExample
+	terraform.Apply(t, terraformOptions)
+
+	example3 := terraform.Output(t, terraformOptions, "example")
+	random3 := terraform.Output(t, terraformOptions, "random")
+
+	assert.NotEqual(t, random, random3, "Expected `random` to change when `example` changed")
+	assert.Equal(t, newExample+" "+random3, example3, "Expected `example` to use new random number")
+
 }

test/src/go.mod

@@ -0,0 +1,12 @@
+module github.com/cloudposse/terraform-example-module
+
+go 1.13
+
+require (
+	github.com/gruntwork-io/terratest v0.28.15
+	github.com/stretchr/testify v1.6.1
+	golang.org/x/crypto v0.0.0-20200820211705-5c72a883971a // indirect
+	golang.org/x/net v0.0.0-20200822124328-c89045814202 // indirect
+	golang.org/x/sys v0.0.0-20200828194041-157a740278f4 // indirect
+	gopkg.in/yaml.v3 v3.0.0-20200615113413-eeeca48fe776 // indirect
+)