diff --git a/builtin/providers/test/provider.go b/builtin/providers/test/provider.go
index 73d347d71..f2c9d376d 100644
--- a/builtin/providers/test/provider.go
+++ b/builtin/providers/test/provider.go
@@ -31,6 +31,7 @@ func Provider() terraform.ResourceProvider {
 			"test_resource_defaults":         testResourceDefaults(),
 			"test_resource_list":             testResourceList(),
 			"test_resource_map":              testResourceMap(),
+			"test_resource_computed_set":     testResourceComputedSet(),
 		},
 		DataSourcesMap: map[string]*schema.Resource{
 			"test_data_source":    testDataSource(),
diff --git a/builtin/providers/test/resource_computed_set.go b/builtin/providers/test/resource_computed_set.go
new file mode 100644
index 000000000..5adf1bd99
--- /dev/null
+++ b/builtin/providers/test/resource_computed_set.go
@@ -0,0 +1,74 @@
+package test
+
+import (
+	"fmt"
+	"math/rand"
+
+	"github.com/hashicorp/terraform/helper/schema"
+)
+
+func testResourceComputedSet() *schema.Resource {
+	return &schema.Resource{
+		Create: testResourceComputedSetCreate,
+		Read:   testResourceComputedSetRead,
+		Delete: testResourceComputedSetDelete,
+		Update: testResourceComputedSetUpdate,
+
+		CustomizeDiff: func(d *schema.ResourceDiff, _ interface{}) error {
+			o, n := d.GetChange("set_count")
+			if o != n {
+				d.SetNewComputed("string_set")
+			}
+			return nil
+		},
+
+		Importer: &schema.ResourceImporter{
+			State: schema.ImportStatePassthrough,
+		},
+
+		Schema: map[string]*schema.Schema{
+			"set_count": {
+				Type:     schema.TypeInt,
+				Optional: true,
+			},
+			"string_set": {
+				Type:     schema.TypeSet,
+				Computed: true,
+				Elem: &schema.Schema{
+					Type: schema.TypeString,
+				},
+				Set: schema.HashString,
+			},
+		},
+	}
+}
+
+func testResourceComputedSetCreate(d *schema.ResourceData, meta interface{}) error {
+	d.SetId(fmt.Sprintf("%x", rand.Int63()))
+	return testResourceComputedSetRead(d, meta)
+}
+
+func testResourceComputedSetRead(d *schema.ResourceData, meta interface{}) error {
+	count := 3
+	v, ok := d.GetOk("set_count")
+	if ok {
+		count = v.(int)
+	}
+
+	var set []interface{}
+	for i := 0; i < count; i++ {
+		set = append(set, fmt.Sprintf("%d", i))
+	}
+
+	d.Set("string_set", schema.NewSet(schema.HashString, set))
+	return nil
+}
+
+func testResourceComputedSetUpdate(d *schema.ResourceData, meta interface{}) error {
+	return testResourceComputedSetRead(d, meta)
+}
+
+func testResourceComputedSetDelete(d *schema.ResourceData, meta interface{}) error {
+	d.SetId("")
+	return nil
+}
diff --git a/builtin/providers/test/resource_computed_set_test.go b/builtin/providers/test/resource_computed_set_test.go
new file mode 100644
index 000000000..806795c1d
--- /dev/null
+++ b/builtin/providers/test/resource_computed_set_test.go
@@ -0,0 +1,52 @@
+package test
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/hashicorp/terraform/helper/resource"
+)
+
+func TestResourceComputedSet_update(t *testing.T) {
+	resource.UnitTest(t, resource.TestCase{
+		Providers:    testAccProviders,
+		CheckDestroy: testAccCheckResourceDestroy,
+		Steps: []resource.TestStep{
+			resource.TestStep{
+				Config: strings.TrimSpace(`
+resource "test_resource_computed_set" "foo" {
+}
+				`),
+				Check: resource.ComposeTestCheckFunc(
+					resource.TestCheckResourceAttr(
+						"test_resource_computed_set.foo", "string_set.#", "3",
+					),
+				),
+			},
+			resource.TestStep{
+				Config: strings.TrimSpace(`
+resource "test_resource_computed_set" "foo" {
+	set_count = 5
+}
+				`),
+				Check: resource.ComposeTestCheckFunc(
+					resource.TestCheckResourceAttr(
+						"test_resource_computed_set.foo", "string_set.#", "5",
+					),
+				),
+			},
+			resource.TestStep{
+				Config: strings.TrimSpace(`
+resource "test_resource_computed_set" "foo" {
+	set_count = 2
+}
+				`),
+				Check: resource.ComposeTestCheckFunc(
+					resource.TestCheckResourceAttr(
+						"test_resource_computed_set.foo", "string_set.#", "2",
+					),
+				),
+			},
+		},
+	})
+}