terraform: test case for cascading input variables (variable to

variable)

terraform/context_test.go

@@ -1474,6 +1474,31 @@ func TestContextPlan_moduleInput(t *testing.T) {
 	}
 }
 
+func TestContextPlan_moduleInputFromVar(t *testing.T) {
+	m := testModule(t, "plan-module-input-var")
+	p := testProvider("aws")
+	p.DiffFn = testDiffFn
+	ctx := testContext(t, &ContextOpts{
+		Module: m,
+		Providers: map[string]ResourceProviderFactory{
+			"aws": testProviderFuncFixed(p),
+		},
+		Variables: map[string]string{
+			"foo": "52",
+		},
+	})
+
+	plan, err := ctx.Plan(nil)
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	actual := strings.TrimSpace(plan.String())
+	expected := strings.TrimSpace(testTerraformPlanModuleInputVarStr)
+	if actual != expected {
+		t.Fatalf("bad:\n%s", actual)
+	}
+}
 func TestContextPlan_moduleOrphans(t *testing.T) {
 	m := testModule(t, "plan-modules-remove")
 	p := testProvider("aws")

terraform/terraform_test.go

@@ -528,6 +528,23 @@ STATE:
 <no state>
 `
 
+const testTerraformPlanModuleInputVarStr = `
+DIFF:
+
+CREATE: aws_instance.bar
+  foo:  "" => "2"
+  type: "" => "aws_instance"
+
+module.child:
+  CREATE: aws_instance.foo
+    foo:  "" => "52"
+    type: "" => "aws_instance"
+
+STATE:
+
+<no state>
+`
+
 const testTerraformPlanModuleOrphansStr = `
 DIFF:
 

terraform/test-fixtures/plan-module-input-var/child/main.tf

@@ -0,0 +1,5 @@
+variable "input" {}
+
+resource "aws_instance" "foo" {
+    foo = "${var.input}"
+}

terraform/test-fixtures/plan-module-input-var/main.tf

@@ -0,0 +1,10 @@
+variable "foo" {}
+
+module "child" {
+    input = "${var.foo}"
+    source = "./child"
+}
+
+resource "aws_instance" "bar" {
+    foo = "2"
+}