diff --git a/builtin/providers/test/resource_data_dep_test.go b/builtin/providers/test/resource_data_dep_test.go
new file mode 100644
index 0000000000..109b4be661
--- /dev/null
+++ b/builtin/providers/test/resource_data_dep_test.go
@@ -0,0 +1,224 @@
+package test
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/hashicorp/terraform/helper/resource"
+	"github.com/hashicorp/terraform/terraform"
+)
+
+// TestResourceDataDep_alignedCountScaleOut tests to make sure interpolation
+// works (namely without index errors) when a data source and a resource share
+// the same count variable during scale-out with an existing state.
+func TestResourceDataDep_alignedCountScaleOut(t *testing.T) {
+	resource.UnitTest(t, resource.TestCase{
+		Providers: testAccProviders,
+		CheckDestroy: func(s *terraform.State) error {
+			return nil
+		},
+		Steps: []resource.TestStep{
+			{
+				Config: testResourceDataDepConfig(2),
+			},
+			{
+				Config: testResourceDataDepConfig(4),
+				Check:  resource.TestCheckOutput("out", "value_from_api,value_from_api,value_from_api,value_from_api"),
+			},
+		},
+	})
+}
+
+// TestResourceDataDep_alignedCountScaleIn tests to make sure interpolation
+// works (namely without index errors) when a data source and a resource share
+// the same count variable during scale-in with an existing state.
+func TestResourceDataDep_alignedCountScaleIn(t *testing.T) {
+	resource.UnitTest(t, resource.TestCase{
+		Providers: testAccProviders,
+		CheckDestroy: func(s *terraform.State) error {
+			return nil
+		},
+		Steps: []resource.TestStep{
+			{
+				Config: testResourceDataDepConfig(4),
+			},
+			{
+				Config: testResourceDataDepConfig(2),
+				Check:  resource.TestCheckOutput("out", "value_from_api,value_from_api"),
+			},
+		},
+	})
+}
+
+// TestDataResourceDep_alignedCountScaleOut functions like
+// TestResourceDataDep_alignedCountScaleOut, but with the dependencies swapped
+// (resource now depends on data source, a pretty regular use case, but
+// included here to check for regressions).
+func TestDataResourceDep_alignedCountScaleOut(t *testing.T) {
+	resource.UnitTest(t, resource.TestCase{
+		Providers: testAccProviders,
+		CheckDestroy: func(s *terraform.State) error {
+			return nil
+		},
+		Steps: []resource.TestStep{
+			{
+				Config: testDataResourceDepConfig(2),
+			},
+			{
+				Config: testDataResourceDepConfig(4),
+				Check:  resource.TestCheckOutput("out", "test,test,test,test"),
+			},
+		},
+	})
+}
+
+// TestDataResourceDep_alignedCountScaleIn functions like
+// TestResourceDataDep_alignedCountScaleIn, but with the dependencies swapped
+// (resource now depends on data source, a pretty regular use case, but
+// included here to check for regressions).
+func TestDataResourceDep_alignedCountScaleIn(t *testing.T) {
+	resource.UnitTest(t, resource.TestCase{
+		Providers: testAccProviders,
+		CheckDestroy: func(s *terraform.State) error {
+			return nil
+		},
+		Steps: []resource.TestStep{
+			{
+				Config: testDataResourceDepConfig(4),
+			},
+			{
+				Config: testDataResourceDepConfig(2),
+				Check:  resource.TestCheckOutput("out", "test,test"),
+			},
+		},
+	})
+}
+
+// TestResourceResourceDep_alignedCountScaleOut functions like
+// TestResourceDataDep_alignedCountScaleOut, but with a resource-to-resource
+// dependency instead, a pretty regular use case, but included here to check
+// for regressions.
+func TestResourceResourceDep_alignedCountScaleOut(t *testing.T) {
+	resource.UnitTest(t, resource.TestCase{
+		Providers: testAccProviders,
+		CheckDestroy: func(s *terraform.State) error {
+			return nil
+		},
+		Steps: []resource.TestStep{
+			{
+				Config: testResourceResourceDepConfig(2),
+			},
+			{
+				Config: testResourceResourceDepConfig(4),
+				Check:  resource.TestCheckOutput("out", "test,test,test,test"),
+			},
+		},
+	})
+}
+
+// TestResourceResourceDep_alignedCountScaleIn functions like
+// TestResourceDataDep_alignedCountScaleIn, but with a resource-to-resource
+// dependency instead, a pretty regular use case, but included here to check
+// for regressions.
+func TestResourceResourceDep_alignedCountScaleIn(t *testing.T) {
+	resource.UnitTest(t, resource.TestCase{
+		Providers: testAccProviders,
+		CheckDestroy: func(s *terraform.State) error {
+			return nil
+		},
+		Steps: []resource.TestStep{
+			{
+				Config: testResourceResourceDepConfig(4),
+			},
+			{
+				Config: testResourceResourceDepConfig(2),
+				Check:  resource.TestCheckOutput("out", "test,test"),
+			},
+		},
+	})
+}
+
+func testResourceDataDepConfig(count int) string {
+	return fmt.Sprintf(`
+variable count {
+  default = "%d"
+}
+
+resource "test_resource" "foo" {
+  count    = "${var.count}"
+  required = "yes"
+
+  required_map = {
+    "foo" = "bar"
+  }
+}
+
+data "test_data_source" "bar" {
+  count = "${var.count}"
+  input = "${test_resource.foo.*.computed_read_only[count.index]}"
+}
+
+output "out" {
+	value = "${join(",", data.test_data_source.bar.*.output)}"
+}
+`, count)
+}
+
+func testDataResourceDepConfig(count int) string {
+	return fmt.Sprintf(`
+variable count {
+  default = "%d"
+}
+
+data "test_data_source" "foo" {
+  count = "${var.count}"
+  input = "test"
+}
+
+resource "test_resource" "bar" {
+  count    = "${var.count}"
+  required = "yes"
+  optional = "${data.test_data_source.foo.*.output[count.index]}"
+
+  required_map = {
+    "foo" = "bar"
+  }
+}
+
+output "out" {
+  value = "${join(",", test_resource.bar.*.optional)}"
+}
+`, count)
+}
+
+func testResourceResourceDepConfig(count int) string {
+	return fmt.Sprintf(`
+variable count {
+  default = "%d"
+}
+
+resource "test_resource" "foo" {
+  count    = "${var.count}"
+  required = "yes"
+  optional = "test"
+
+  required_map = {
+    "foo" = "bar"
+  }
+}
+
+resource "test_resource" "bar" {
+  count    = "${var.count}"
+  required = "yes"
+  optional = "${test_resource.foo.*.optional[count.index]}"
+
+  required_map = {
+    "foo" = "bar"
+  }
+}
+
+output "out" {
+  value = "${join(",", test_resource.bar.*.optional)}"
+}
+`, count)
+}