From 79dbd07679298e7dea0674aef32d3d8281a2bb97 Mon Sep 17 00:00:00 2001
From: Mitchell Hashimoto <mitchell.hashimoto@gmail.com>
Date: Wed, 16 Jul 2014 18:32:36 -0700
Subject: [PATCH] providers/aws: no empty security groups when flattening ip
 perms

/cc @pearkes - A few things here:

First, this fixes the issue you mentioned to be in chat. Basically: if
there are no security groups, don't put it into flatten, because flatten
will include a "key.#" = "0".

Next, I transformed your test into a "table-driven" test which are really
nice to write and maintain. Basically, as you find bugs or edge cases, you can
just add to the table and you get the test for free. I recommend these
whereever you have a pure input to output sort of data transformation
function.
---
 builtin/providers/aws/structure.go      |  6 ++-
 builtin/providers/aws/structure_test.go | 72 ++++++++++++++++++-------
 2 files changed, 57 insertions(+), 21 deletions(-)

diff --git a/builtin/providers/aws/structure.go b/builtin/providers/aws/structure.go
index 06f61b76e..b8669d97f 100644
--- a/builtin/providers/aws/structure.go
+++ b/builtin/providers/aws/structure.go
@@ -80,7 +80,11 @@ func flattenIPPerms(list []ec2.IPPerm) []map[string]interface{} {
 		n["protocol"] = perm.Protocol
 		n["to_port"] = perm.ToPort
 		n["cidr_blocks"] = perm.SourceIPs
-		n["security_groups"] = flattenSecurityGroups(perm.SourceGroups)
+
+		if v := flattenSecurityGroups(perm.SourceGroups); len(v) > 0 {
+			n["security_groups"] = v
+		}
+
 		result = append(result, n)
 	}
 
diff --git a/builtin/providers/aws/structure_test.go b/builtin/providers/aws/structure_test.go
index c114d06e0..803e4f376 100644
--- a/builtin/providers/aws/structure_test.go
+++ b/builtin/providers/aws/structure_test.go
@@ -56,31 +56,63 @@ func Test_expandIPPerms(t *testing.T) {
 }
 
 func Test_flattenIPPerms(t *testing.T) {
-	rawIp := []ec2.IPPerm{
-		ec2.IPPerm{
-			Protocol:  "icmp",
-			FromPort:  1,
-			ToPort:    -1,
-			SourceIPs: []string{"0.0.0.0/0"},
-			SourceGroups: []ec2.UserSecurityGroup{
-				ec2.UserSecurityGroup{
-					Id: "sg-11111",
+	cases := []struct {
+		Input  []ec2.IPPerm
+		Output []map[string]interface{}
+	}{
+		{
+			Input: []ec2.IPPerm{
+				ec2.IPPerm{
+					Protocol:  "icmp",
+					FromPort:  1,
+					ToPort:    -1,
+					SourceIPs: []string{"0.0.0.0/0"},
+					SourceGroups: []ec2.UserSecurityGroup{
+						ec2.UserSecurityGroup{
+							Id: "sg-11111",
+						},
+					},
+				},
+			},
+
+			Output: []map[string]interface{}{
+				map[string]interface{}{
+					"protocol":        "icmp",
+					"from_port":       1,
+					"to_port":         -1,
+					"cidr_blocks":     []string{"0.0.0.0/0"},
+					"security_groups": []string{"sg-11111"},
+				},
+			},
+		},
+
+		{
+			Input: []ec2.IPPerm{
+				ec2.IPPerm{
+					Protocol:     "icmp",
+					FromPort:     1,
+					ToPort:       -1,
+					SourceIPs:    []string{"0.0.0.0/0"},
+					SourceGroups: nil,
+				},
+			},
+
+			Output: []map[string]interface{}{
+				map[string]interface{}{
+					"protocol":    "icmp",
+					"from_port":   1,
+					"to_port":     -1,
+					"cidr_blocks": []string{"0.0.0.0/0"},
 				},
 			},
 		},
 	}
 
-	toFlatten := make(map[string]interface{})
-	toFlatten["ingress"] = flattenIPPerms(rawIp)
-
-	perms := flatmap.Flatten(toFlatten)
-
-	if perms["ingress.0.protocol"] != "icmp" {
-		t.Fatalf("bad protocol")
-	}
-
-	if perms["ingress.0.security_groups.0"] != "sg-11111" {
-		t.Fatalf("bad security group")
+	for _, tc := range cases {
+		output := flattenIPPerms(tc.Input)
+		if !reflect.DeepEqual(output, tc.Output) {
+			t.Fatalf("Input:\n\n%#v\n\nOutput:\n\n%#v", tc.Input, output)
+		}
 	}
 }