graph: update format for v1.7 (#424)

tfexec/graph.go

diff --git a/tfexec/graph.go b/tfexec/graph.go
index 1b28aa5..0f8b0ee 100644
--- a/tfexec/graph.go
+++ b/tfexec/graph.go
@@ -60,7 +60,7 @@
 	args := []string{"graph"}
 
 	if c.plan != "" {
-		// plan was a positional arguement prior to Terraform 0.15.0. Ensure proper use by checking version.
+		// plan was a positional argument prior to Terraform 0.15.0. Ensure proper use by checking version.
 		if err := tf.compatible(ctx, tf0_15_0, nil); err == nil {
 			args = append(args, "-plan="+c.plan)
 		} else {

tfexec/internal/e2etest/graph_test.go

diff --git a/tfexec/internal/e2etest/graph_test.go b/tfexec/internal/e2etest/graph_test.go
index 715e189..aea432f 100644
--- a/tfexec/internal/e2etest/graph_test.go
+++ b/tfexec/internal/e2etest/graph_test.go
@@ -96,8 +96,9 @@
 `
 	}
 
-	// 1.1.0+
-	return `digraph {
+	if v.GreaterThanOrEqual(v1_1) && v.LessThan(v1_7) {
+		// 1.1.0 - 1.7.0
+		return `digraph {
 	compound = "true"
 	newrank = "true"
 	subgraph "root" {
@@ -110,4 +111,13 @@
 }
 
 `
+	}
+
+	// 1.7.0+
+	return `digraph G {
+  rankdir = "RL";
+  node [shape = rect, fontname = "sans-serif"];
+  "null_resource.foo" [label="null_resource.foo"];
+}
+`
 }

tfexec/internal/e2etest/providers_schema_test.go

diff --git a/tfexec/internal/e2etest/providers_schema_test.go b/tfexec/internal/e2etest/providers_schema_test.go
index 97979fc..cafce80 100644
--- a/tfexec/internal/e2etest/providers_schema_test.go
+++ b/tfexec/internal/e2etest/providers_schema_test.go
@@ -22,6 +22,7 @@
 	v0_15_0 = version.Must(version.NewVersion("0.15.0"))
 	v1_0    = version.Must(version.NewVersion("1.0.0"))
 	v1_1    = version.Must(version.NewVersion("1.1.0"))
+	v1_7    = version.Must(version.NewVersion("1.7.0"))
 )
 
 func TestProvidersSchema(t *testing.T) {