feat: Add support for validating Output Changes

modules/terraform/plan_struct.go

@@ -25,6 +25,9 @@ type PlanStruct struct {
 	// A map that maps full resource addresses (e.g., module.foo.null_resource.test) to the planned actions terraform
 	// will take on that resource.
 	ResourceChangesMap map[string]*tfjson.ResourceChange
+
+	// A map that maps the output name to the planned values of that output
+	OutputChangesMap map[string]*tfjson.Change
 }
 
 // ParsePlanJSON takes in the json string representation of the terraform plan and returns a go struct representation
@@ -36,11 +39,22 @@ func ParsePlanJSON(jsonStr string) (*PlanStruct, error) {
 		return nil, err
 	}
 
+	plan.OutputChangesMap = parseOutputChanges(plan)
 	plan.ResourcePlannedValuesMap = parsePlannedValues(plan)
 	plan.ResourceChangesMap = parseResourceChanges(plan)
 	return plan, nil
 }
 
+// parseOutputChanges takes a plan and returns a maps that maps output names to the planned changes for that output.
+// If there are no changes, this returns an empty map instead of erroring
+func parseOutputChanges(plan *PlanStruct) map[string]*tfjson.Change {
+	out := map[string]*tfjson.Change{}
+	for outputName, change := range plan.RawPlan.OutputChanges {
+		out[outputName] = change
+	}
+	return out
+}
+
 // parseResourceChanges takes a plan and returns a map that maps resource addresses to the planned changes for that
 // resource. If there are no changes, this returns an empty map instead of erroring.
 func parseResourceChanges(plan *PlanStruct) map[string]*tfjson.ResourceChange {
@@ -91,6 +105,18 @@ func parseModulePlannedValues(module *tfjson.StateModule) map[string]*tfjson.Sta
 	return out
 }
 
+// AssertOutputChangesMapKeyExists checks if the given key exists in the map, failing the test if it does not.
+func AssertOutputChangesMapKeyExists(t testing.TestingT, plan *PlanStruct, keyQuery string) {
+	_, hasKey := plan.OutputChangesMap[keyQuery]
+	assert.Truef(t, hasKey, "Given output changes map does not have key %s", keyQuery)
+}
+
+// RequireOutputChangesMapKeyExists checks if the given key exists in the map, failing and halting the test if it does not.
+func RequireOutputChangesMapKeyExists(t testing.TestingT, plan *PlanStruct, keyQuery string) {
+	_, hasKey := plan.OutputChangesMap[keyQuery]
+	require.Truef(t, hasKey, "Given output changes map does not have key %s", keyQuery)
+}
+
 // AssertPlannedValuesMapKeyExists checks if the given key exists in the map, failing the test if it does not.
 func AssertPlannedValuesMapKeyExists(t testing.TestingT, plan *PlanStruct, keyQuery string) {
 	_, hasKey := plan.ResourcePlannedValuesMap[keyQuery]

modules/terraform/plan_struct_test.go

@@ -4,6 +4,7 @@ import (
 	"testing"
 
 	http_helper "github.com/gruntwork-io/terratest/modules/http-helper"
+	tfjson "github.com/hashicorp/terraform-json"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
@@ -12,17 +13,23 @@ const (
 	// NOTE: We pull down the json files from github during test runtime as opposed to checking it in as these source
 	// files are licensed under MPL and we want to avoid a dual license scenario where some source files in terratest
 	// are licensed under a different license.
-	basicJsonUrl      = "https://raw.githubusercontent.com/hashicorp/terraform-json/v0.8.0/testdata/basic/plan.json"
-	deepModuleJsonUrl = "https://raw.githubusercontent.com/hashicorp/terraform-json/v0.8.0/testdata/deep_module/plan.json"
+	basicJsonUrl      = "https://raw.githubusercontent.com/hashicorp/terraform-json/v0.13.0/testdata/basic/plan.json"
+	deepModuleJsonUrl = "https://raw.githubusercontent.com/hashicorp/terraform-json/v0.13.0/testdata/deep_module/plan.json"
 
-	changesJsonUrl = "https://raw.githubusercontent.com/hashicorp/terraform-json/v0.8.0/testdata/has_changes/plan.json"
+	changesJsonUrl = "https://raw.githubusercontent.com/hashicorp/terraform-json/v0.13.0/testdata/has_changes/plan.json"
 )
 
+func validateHTTPSuccess(statusCode int) bool {
+	return statusCode >= 200 && statusCode < 300
+}
+
 func TestPlannedValuesMapWithBasicJson(t *testing.T) {
 	t.Parallel()
 
 	// Retrieve test data from the terraform-json project.
-	_, jsonData := http_helper.HttpGet(t, basicJsonUrl, nil)
+	statusCode, jsonData := http_helper.HttpGet(t, basicJsonUrl, nil)
+	require.True(t, validateHTTPSuccess(statusCode))
+
 	plan, err := ParsePlanJSON(jsonData)
 	require.NoError(t, err)
 
@@ -47,7 +54,9 @@ func TestPlannedValuesMapWithDeepModuleJson(t *testing.T) {
 	t.Parallel()
 
 	// Retrieve test data from the terraform-json project.
-	_, jsonData := http_helper.HttpGet(t, deepModuleJsonUrl, nil)
+	statusCode, jsonData := http_helper.HttpGet(t, deepModuleJsonUrl, nil)
+	require.True(t, validateHTTPSuccess(statusCode))
+
 	plan, err := ParsePlanJSON(jsonData)
 	require.NoError(t, err)
 
@@ -63,7 +72,9 @@ func TestResourceChangesJson(t *testing.T) {
 	t.Parallel()
 
 	// Retrieve test data from the terraform-json project.
-	_, jsonData := http_helper.HttpGet(t, changesJsonUrl, nil)
+	statusCode, jsonData := http_helper.HttpGet(t, changesJsonUrl, nil)
+	require.True(t, validateHTTPSuccess(statusCode))
+
 	plan, err := ParsePlanJSON(jsonData)
 	require.NoError(t, err)
 
@@ -77,5 +88,28 @@ func TestResourceChangesJson(t *testing.T) {
 	barChanges := plan.ResourceChangesMap["null_resource.bar"]
 	require.NotNil(t, barChanges.Change)
 	assert.Equal(t, barChanges.Change.After.(map[string]interface{})["triggers"].(map[string]interface{})["foo_id"].(string), "424881806176056736")
+}
+
+func TestOutputChangesJson(t *testing.T) {
+	t.Parallel()
+
+	// Retrieve test data from the terraform-json project.
+	statusCode, jsonData := http_helper.HttpGet(t, changesJsonUrl, nil)
+	require.True(t, validateHTTPSuccess(statusCode))
+
+	plan, err := ParsePlanJSON(jsonData)
+	require.NoError(t, err)
+
+	// Spot check a few changes to make sure the right address was registered
+	RequireOutputChangesMapKeyExists(t, plan, "foo")
+	fooChanges := plan.OutputChangesMap["foo"]
+	require.NotNil(t, fooChanges)
+	assert.Equal(t, fooChanges.Actions, tfjson.Actions{"create"})
+	assert.Equal(t, fooChanges.After, "bar")
 
+	AssertOutputChangesMapKeyExists(t, plan, "map")
+	mapChanges := plan.OutputChangesMap["map"]
+	require.NotNil(t, mapChanges)
+	assert.Equal(t, mapChanges.Actions, tfjson.Actions{"create"})
+	assert.Equal(t, mapChanges.After.(map[string]interface{}), map[string]interface{}{"foo": "bar", "number": float64(42)})
 }