chore(tmc): use real terraform in e2e tests (#1177)

## Reasons for this change

Before we used a fake terraform binary that mimicked some Terraform
behavior and it supported fully customization of the program's output.
The problem is that the fake terraform misses a lot of important
details:
- `terraform show` gives different error messages depending on different
requirements not met.
- `terraform show` requires an initialized terraform module and then
mimicking this behavior is hard.
- `terraform show` checks the lock files
- etc

if we ignore those details, we miss the opportunity to test those cases
and improve Terramate error messages for such errors.
_The error message improvements are not addressed in this PR_.

## Changes

- Now during the e2e test setup, the Terraform is installed in a temp
directory using the hashicorp official `hc-install` library.
- Tests were updated to use a real project.
- Sandbox library updated to support `copy` and `run` commands.

cmd/terramate/e2etests/_testdata/cloud-sync-drift-plan-file/main.tf

@@ -0,0 +1,13 @@
+/**
+ * Copyright 2023 Terramate GmbH
+ * SPDX-License-Identifier: MPL-2.0
+ */
+
+resource "local_file" "foo" {
+  content  = var.content
+  filename = "${path.module}/foo.bar"
+}
+
+variable "content" {
+  sensitive = true
+}

cmd/terramate/e2etests/_testdata/cloud-sync-drift-plan-file/sanitized.plan.json

@@ -0,0 +1 @@
+{"format_version":"1.2","terraform_version":"1.5.0","variables":{"content":{"value":"REDACTED_SENSITIVE"}},"planned_values":{"root_module":{"resources":[{"address":"local_file.foo","mode":"managed","type":"local_file","name":"foo","provider_name":"registry.terraform.io/hashicorp/local","schema_version":0,"values":{"content":"REDACTED_SENSITIVE","content_base64":null,"directory_permission":"0777","file_permission":"0777","filename":"./foo.bar","sensitive_content":"REDACTED_SENSITIVE","source":null},"sensitive_values":{"content":true}}]}},"resource_changes":[{"address":"local_file.foo","mode":"managed","type":"local_file","name":"foo","provider_name":"registry.terraform.io/hashicorp/local","change":{"actions":["create"],"before":null,"after":{"content":"REDACTED_SENSITIVE","content_base64":null,"directory_permission":"0777","file_permission":"0777","filename":"./foo.bar","sensitive_content":"REDACTED_SENSITIVE","source":null},"after_unknown":{"content_base64sha256":true,"content_base64sha512":true,"content_md5":true,"content_sha1":true,"content_sha256":true,"content_sha512":true,"id":true},"before_sensitive":false,"after_sensitive":{"content":true,"sensitive_content":true}}}],"configuration":{"provider_config":{"local":{"name":"local","full_name":"registry.terraform.io/hashicorp/local"}},"root_module":{"resources":[{"address":"local_file.foo","mode":"managed","type":"local_file","name":"foo","provider_config_key":"local","expressions":{"content":{"references":["var.content"]},"filename":{"references":["path.module"]}},"schema_version":0}],"variables":{"content":{"sensitive":true}}}},"timestamp":"2023-10-12T14:03:39Z"}

cmd/terramate/e2etests/cmd/test/helper.go → cmd/terramate/e2etests/cmd/helper/main.go

@@ -1,7 +1,7 @@
 // Copyright 2023 Terramate GmbH
 // SPDX-License-Identifier: MPL-2.0
 
-// test is a test command that implements behaviors that are
+// helper is a utility command that implements behaviors that are
 // useful when testing terramate run features in a way that reduces
 // dependencies on the environment to run the tests.
 package main
@@ -20,7 +20,7 @@ import (
 	"github.com/hashicorp/terraform-json/sanitize"
 )
 
-func helper() {
+func main() {
 	if len(os.Args) < 2 {
 		log.Fatalf("%s requires at least one subcommand argument", os.Args[0])
 	}

cmd/terramate/e2etests/main_test.go

@@ -4,22 +4,32 @@
 package e2etest
 
 import (
+	"context"
 	"fmt"
-	"io/ioutil"
 	"log"
 	"os"
 	"os/exec"
 	"path/filepath"
 	"runtime"
 	"testing"
+	"time"
 
+	"github.com/hashicorp/go-version"
+	install "github.com/hashicorp/hc-install"
+	"github.com/hashicorp/hc-install/product"
+	"github.com/hashicorp/hc-install/releases"
+	"github.com/hashicorp/hc-install/src"
 	"github.com/terramate-io/terramate/errors"
-	"github.com/terramate-io/terramate/test"
 )
 
+const terraformVersion = "1.5.0"
+
 // terramateTestBin is the path to the terramate binary we compiled for test purposes
 var terramateTestBin string
 
+// terraformTestBin is the path to the installed terraform binary.
+var terraformTestBin string
+
 // testHelperBin is the path to the test binary we compiled for test purposes
 var testHelperBin string
 
@@ -67,7 +77,7 @@ func setupAndRunTests(m *testing.M) (status int) {
 		return 1
 	}
 
-	testCmdPath := filepath.Join(packageDir, "cmd", "test")
+	testCmdPath := filepath.Join(packageDir, "cmd", "helper")
 	testHelperBin, err = buildTestHelper(goBin, testCmdPath, binTmpDir)
 	if err != nil {
 		log.Printf("failed to setup e2e tests: %v", err)
@@ -79,6 +89,21 @@ func setupAndRunTests(m *testing.M) (status int) {
 	EOF
 	)}`, testHelperBin)
 
+	tfExecPath, installer, err := installTerraform()
+	if err != nil {
+		log.Printf("failed to setup Terraform binary")
+		return 1
+	}
+
+	terraformTestBin = tfExecPath
+
+	defer func() {
+		err := installer.Remove(context.Background())
+		if err != nil {
+			log.Printf("failed to remove terraform installation")
+		}
+	}()
+
 	return m.Run()
 }
 
@@ -95,17 +120,6 @@ func buildTestHelper(goBin, testCmdPath, binDir string) (string, error) {
 	if err != nil {
 		return "", fmt.Errorf("failed to build test helper: %v (output: %s)", err, string(out))
 	}
-	data, err := ioutil.ReadFile(outBinPath)
-	if err != nil {
-		return "", errors.E(err, "reading helper binary")
-	}
-
-	tfPath := filepath.Join(binDir, "terraform"+platExeSuffix())
-	err = ioutil.WriteFile(tfPath, data, 0644)
-	if err != nil {
-		return "", errors.E(err, "writing fake terraform binary")
-	}
-	err = test.Chmod(tfPath, 0550)
 	return outBinPath, err
 }
 
@@ -132,6 +146,25 @@ func buildTerramate(goBin, projectRoot, binDir string) (string, error) {
 	return outBinPath, nil
 }
 
+func installTerraform() (string, *install.Installer, error) {
+	ctx, cancel := context.WithTimeout(context.Background(), 1*time.Minute)
+	defer cancel()
+
+	installer := install.NewInstaller()
+	version := version.Must(version.NewVersion(terraformVersion))
+
+	execPath, err := installer.Install(ctx, []src.Installable{
+		&releases.ExactVersion{
+			Product: product.Terraform,
+			Version: version,
+		},
+	})
+	if err != nil {
+		return "", nil, errors.E(err, "installing Terraform")
+	}
+	return execPath, installer, nil
+}
+
 func lookupGoBin() (string, error) {
 	exeSuffix := platExeSuffix()
 	path := filepath.Join(runtime.GOROOT(), "bin", "go"+exeSuffix)