feat: add *WithFilter helper functions

modules/files/files.go

@@ -10,6 +10,17 @@ import (
 	"github.com/mattn/go-zglob"
 )
 
+// DefaultPathFilter is the default filter used by CopyTerraformFolderToDest to determine which files to copy.
+func DefaultPathFilter(path string) bool {
+	if PathIsTerraformVersionFile(path) || PathIsTerraformLockFile(path) {
+		return true
+	}
+	if PathContainsHiddenFileOrFolder(path) || PathContainsTerraformStateOrVars(path) {
+		return false
+	}
+	return true
+}
+
 // FileExists returns true if the given file exists.
 func FileExists(path string) bool {
 	_, err := os.Stat(path)
@@ -38,24 +49,12 @@ func IsExistingDir(path string) bool {
 	return err == nil && fileInfo.IsDir()
 }
 
-// CopyTerraformFolderToDest creates a copy of the given folder and all its contents in a specified folder with a unique name and the given prefix.
+// CopyTerraformFolderToDestWithFilter creates a copy of the given folder and all its contents in a specified folder with a unique name and the given prefix.
 // This is useful when running multiple tests in parallel against the same set of Terraform files to ensure the
 // tests don't overwrite each other's .terraform working directory and terraform.tfstate files. This method returns
-// the path to the dest folder with the copied contents. Hidden files and folders (with the exception of the `.terraform-version` files used
-// by the [tfenv tool](https://github.com/tfutils/tfenv) and `.terraform.lock.hcl` used by Terraform to lock providers versions), Terraform state
-// files, and terraform.tfvars files are not copied to this temp folder, as you typically don't want them interfering with your tests.
+// the path to the dest folder with the copied contents. You can configure which files you want to copy by passing in a filter function.
 // This method is useful when running through a build tool so the files are copied to a destination that is cleaned on each run of the pipeline.
-func CopyTerraformFolderToDest(folderPath string, destRootFolder string, tempFolderPrefix string) (string, error) {
-	filter := func(path string) bool {
-		if PathIsTerraformVersionFile(path) || PathIsTerraformLockFile(path) {
-			return true
-		}
-		if PathContainsHiddenFileOrFolder(path) || PathContainsTerraformStateOrVars(path) {
-			return false
-		}
-		return true
-	}
-
+func CopyTerraformFolderToDestWithFilter(folderPath string, destRootFolder string, tempFolderPrefix string, filter func(string) bool) (string, error) {
 	destFolder, err := CopyFolderToDest(folderPath, destRootFolder, tempFolderPrefix, filter)
 	if err != nil {
 		return "", err
@@ -64,6 +63,22 @@ func CopyTerraformFolderToDest(folderPath string, destRootFolder string, tempFol
 	return destFolder, nil
 }
 
+// CopyTerraformFolderToDest creates a copy of the given folder and all its contents in a specified folder with a unique name and the given prefix.
+// This is useful when running multiple tests in parallel against the same set of Terraform files to ensure the
+// tests don't overwrite each other's .terraform working directory and terraform.tfstate files. This method returns
+// the path to the dest folder with the copied contents. Hidden files and folders (with the exception of the `.terraform-version` files used
+// by the [tfenv tool](https://github.com/tfutils/tfenv) and `.terraform.lock.hcl` used by Terraform to lock providers versions), Terraform state
+// files, and terraform.tfvars files are not copied to this temp folder, as you typically don't want them interfering with your tests.
+// This method is useful when running through a build tool so the files are copied to a destination that is cleaned on each run of the pipeline.
+func CopyTerraformFolderToDest(folderPath string, destRootFolder string, tempFolderPrefix string) (string, error) {
+	return CopyTerraformFolderToDestWithFilter(folderPath, destRootFolder, tempFolderPrefix, DefaultPathFilter)
+}
+
+// CopyTerraformFolderToTempWithFilter calls CopyTerraformFolderToDestWithFilter, passing os.TempDir() as the root destination folder.
+func CopyTerraformFolderToTempWithFilter(folderPath string, tempFolderPrefix string, filter func(string) bool) (string, error) {
+	return CopyTerraformFolderToDestWithFilter(folderPath, os.TempDir(), tempFolderPrefix, filter)
+}
+
 // CopyTerraformFolderToTemp calls CopyTerraformFolderToDest, passing os.TempDir() as the root destination folder.
 func CopyTerraformFolderToTemp(folderPath string, tempFolderPrefix string) (string, error) {
 	return CopyTerraformFolderToDest(folderPath, os.TempDir(), tempFolderPrefix)

modules/test-structure/test_structure.go

@@ -43,6 +43,37 @@ func SkipStageEnvVarSet() bool {
 	return false
 }
 
+// CopyTerraformFolderToTempWithFilter copies the given root folder to a randomly-named temp folder and return the path to the
+// given terraform modules folder within the new temp root folder. This is useful when running multiple tests in
+// parallel against the same set of Terraform files to ensure the tests don't overwrite each other's .terraform working
+// directory and terraform.tfstate files. To ensure relative paths work, we copy over the entire root folder to a temp
+// folder, and then return the path within that temp folder to the given terraform module dir, which is where the actual
+// test will be running.
+// For example, suppose you had the target terraform folder you want to test in "/examples/terraform-aws-example"
+// relative to the repo root. If your tests reside in the "/test" relative to the root, then you will use this as
+// follows:
+//
+//	// Root folder where terraform files should be (relative to the test folder)
+//	rootFolder := ".."
+//
+//	// Relative path to terraform module being tested from the root folder
+//	terraformFolderRelativeToRoot := "examples/terraform-aws-example"
+//
+//	// Copy the terraform folder to a temp folder
+//	tempTestFolder := test_structure.CopyTerraformFolderToTemp(t, rootFolder, terraformFolderRelativeToRoot)
+//
+//	// Make sure to use the temp test folder in the terraform options
+//	terraformOptions := &terraform.Options{
+//			TerraformDir: tempTestFolder,
+//	}
+//
+// Note that if any of the SKIP_<stage> environment variables is set, we assume this is a test in the local dev where
+// there are no other concurrent tests running and we want to be able to cache test data between test stages, so in that
+// case, we do NOT copy anything to a temp folder, and return the path to the original terraform module folder instead.
+func CopyTerraformFolderToTempWithFilter(t testing.TestingT, rootFolder string, terraformModuleFolder string, filter func(string) bool) string {
+	return CopyTerraformFolderToDestWithFilter(t, rootFolder, terraformModuleFolder, os.TempDir(), filter)
+}
+
 // CopyTerraformFolderToTemp copies the given root folder to a randomly-named temp folder and return the path to the
 // given terraform modules folder within the new temp root folder. This is useful when running multiple tests in
 // parallel against the same set of Terraform files to ensure the tests don't overwrite each other's .terraform working
@@ -74,7 +105,7 @@ func CopyTerraformFolderToTemp(t testing.TestingT, rootFolder string, terraformM
 	return CopyTerraformFolderToDest(t, rootFolder, terraformModuleFolder, os.TempDir())
 }
 
-// CopyTerraformFolderToDest copies the given root folder to a randomly-named temp folder and return the path to the
+// CopyTerraformFolderToDestWithFilter copies the given root folder to a randomly-named temp folder and return the path to the
 // given terraform modules folder within the new temp root folder. This is useful when running multiple tests in
 // parallel against the same set of Terraform files to ensure the tests don't overwrite each other's .terraform working
 // directory and terraform.tfstate files. To ensure relative paths work, we copy over the entire root folder to a temp
@@ -105,7 +136,7 @@ func CopyTerraformFolderToTemp(t testing.TestingT, rootFolder string, terraformM
 // Note that if any of the SKIP_<stage> environment variables is set, we assume this is a test in the local dev where
 // there are no other concurrent tests running and we want to be able to cache test data between test stages, so in that
 // case, we do NOT copy anything to a temp folder, and return the path to the original terraform module folder instead.
-func CopyTerraformFolderToDest(t testing.TestingT, rootFolder string, terraformModuleFolder string, destRootFolder string) string {
+func CopyTerraformFolderToDestWithFilter(t testing.TestingT, rootFolder string, terraformModuleFolder string, destRootFolder string, filter func(string) bool) string {
 	if SkipStageEnvVarSet() {
 		logger.Logf(t, "A SKIP_XXX environment variable is set. Using original examples folder rather than a temp folder so we can cache data between stages for faster local testing.")
 		return filepath.Join(rootFolder, terraformModuleFolder)
@@ -119,7 +150,7 @@ func CopyTerraformFolderToDest(t testing.TestingT, rootFolder string, terraformM
 		t.Fatal(files.DirNotFoundError{Directory: fullTerraformModuleFolder})
 	}
 
-	tmpRootFolder, err := files.CopyTerraformFolderToDest(rootFolder, destRootFolder, cleanName(t.Name()))
+	tmpRootFolder, err := files.CopyTerraformFolderToDestWithFilter(rootFolder, destRootFolder, cleanName(t.Name()), filter)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -132,6 +163,41 @@ func CopyTerraformFolderToDest(t testing.TestingT, rootFolder string, terraformM
 	return tmpTestFolder
 }
 
+// CopyTerraformFolderToDest copies the given root folder to a randomly-named temp folder and return the path to the
+// given terraform modules folder within the new temp root folder. This is useful when running multiple tests in
+// parallel against the same set of Terraform files to ensure the tests don't overwrite each other's .terraform working
+// directory and terraform.tfstate files. To ensure relative paths work, we copy over the entire root folder to a temp
+// folder, and then return the path within that temp folder to the given terraform module dir, which is where the actual
+// test will be running.
+// For example, suppose you had the target terraform folder you want to test in "/examples/terraform-aws-example"
+// relative to the repo root. If your tests reside in the "/test" relative to the root, then you will use this as
+// follows:
+//
+//	// Destination for the copy of the files.  In this example we are using the Azure Dev Ops variable
+//	// for the folder that is cleaned after each pipeline job.
+//	destRootFolder := os.Getenv("AGENT_TEMPDIRECTORY")
+//
+//	// Root folder where terraform files should be (relative to the test folder)
+//	rootFolder := ".."
+//
+//	// Relative path to terraform module being tested from the root folder
+//	terraformFolderRelativeToRoot := "examples/terraform-aws-example"
+//
+//	// Copy the terraform folder to a temp folder
+//	tempTestFolder := test_structure.CopyTerraformFolderToTemp(t, rootFolder, terraformFolderRelativeToRoot, destRootFolder)
+//
+//	// Make sure to use the temp test folder in the terraform options
+//	terraformOptions := &terraform.Options{
+//			TerraformDir: tempTestFolder,
+//	}
+//
+// Note that if any of the SKIP_<stage> environment variables is set, we assume this is a test in the local dev where
+// there are no other concurrent tests running and we want to be able to cache test data between test stages, so in that
+// case, we do NOT copy anything to a temp folder, and return the path to the original terraform module folder instead.
+func CopyTerraformFolderToDest(t testing.TestingT, rootFolder string, terraformModuleFolder string, destRootFolder string) string {
+	return CopyTerraformFolderToDestWithFilter(t, rootFolder, terraformModuleFolder, destRootFolder, files.DefaultPathFilter)
+}
+
 func cleanName(originalName string) string {
 	parts := strings.Split(originalName, "/")
 	return parts[len(parts)-1]