From fceea12adea988f018b6fbab276797e446ca42a1 Mon Sep 17 00:00:00 2001
From: Mitchell Hashimoto <mitchell.hashimoto@gmail.com>
Date: Mon, 30 Jun 2014 21:25:15 -0700
Subject: [PATCH] terraform: some basic validation

---
 terraform/graph.go      | 4 ++++
 terraform/graph_test.go | 6 ++++++
 2 files changed, 10 insertions(+)

diff --git a/terraform/graph.go b/terraform/graph.go
index a464b0c6f6..002b7ae9ce 100644
--- a/terraform/graph.go
+++ b/terraform/graph.go
@@ -77,6 +77,10 @@ type GraphNodeResourceProvider struct {
 //     configured at this point.
 //
 func Graph(opts *GraphOpts) (*depgraph.Graph, error) {
+	if opts.Config == nil {
+		return nil, errors.New("Config is required for Graph")
+	}
+
 	g := new(depgraph.Graph)
 
 	// First, build the initial resource graph. This only has the resources
diff --git a/terraform/graph_test.go b/terraform/graph_test.go
index 04821ed668..cb38bcd65b 100644
--- a/terraform/graph_test.go
+++ b/terraform/graph_test.go
@@ -21,6 +21,12 @@ func TestGraph(t *testing.T) {
 	}
 }
 
+func TestGraph_configRequired(t *testing.T) {
+	if _, err := Graph(new(GraphOpts)); err == nil {
+		t.Fatal("should error")
+	}
+}
+
 func TestGraph_cycle(t *testing.T) {
 	config := testConfig(t, "graph-cycle")