diff --git a/terraform/plan.go b/terraform/plan.go
index b7bc9f1598..d765775cf3 100644
--- a/terraform/plan.go
+++ b/terraform/plan.go
@@ -5,6 +5,7 @@ import (
 	"errors"
 	"fmt"
 	"io"
+	"sync"
 
 	"github.com/hashicorp/terraform/config"
 )
@@ -16,6 +17,30 @@ type Plan struct {
 	Diff   *Diff
 	State  *State
 	Vars   map[string]string
+
+	once sync.Once
+}
+
+func (p *Plan) String() string {
+	return p.Diff.String()
+}
+
+func (p *Plan) init() {
+	p.once.Do(func() {
+		if p.Diff == nil {
+			p.Diff = new(Diff)
+			p.Diff.init()
+		}
+
+		if p.State == nil {
+			p.State = new(State)
+			p.State.init()
+		}
+
+		if p.Vars == nil {
+			p.Vars = make(map[string]string)
+		}
+	})
 }
 
 // The format byte is prefixed into the plan file format so that we have
diff --git a/terraform/terraform.go b/terraform/terraform.go
index e9546c7d22..0f23abd048 100644
--- a/terraform/terraform.go
+++ b/terraform/terraform.go
@@ -113,9 +113,9 @@ func (t *Terraform) Apply(s *State, d *Diff) (*State, error) {
 	return result, nil
 }
 
-func (t *Terraform) Diff(s *State) (*Diff, error) {
-	result := new(Diff)
-	err := t.graph.Walk(t.diffWalkFn(s, result))
+func (t *Terraform) Plan(s *State) (*Plan, error) {
+	result := new(Plan)
+	err := t.graph.Walk(t.planWalkFn(s, result))
 	if err != nil {
 		return nil, err
 	}
@@ -165,8 +165,8 @@ func (t *Terraform) applyWalkFn(
 	return t.genericWalkFn(state, diff, cb)
 }
 
-func (t *Terraform) diffWalkFn(
-	state *State, result *Diff) depgraph.WalkFunc {
+func (t *Terraform) planWalkFn(
+	state *State, result *Plan) depgraph.WalkFunc {
 	var l sync.Mutex
 
 	// Initialize the result diff so we can write to it
@@ -192,7 +192,7 @@ func (t *Terraform) diffWalkFn(
 
 		// Update the resulting diff
 		l.Lock()
-		result.Resources[r.Id] = diff
+		result.Diff.Resources[r.Id] = diff
 		l.Unlock()
 
 		// Determine the new state and update variables
diff --git a/terraform/terraform_test.go b/terraform/terraform_test.go
index fdc1b80ff4..c77e790b41 100644
--- a/terraform/terraform_test.go
+++ b/terraform/terraform_test.go
@@ -203,6 +203,7 @@ func TestNew_variables(t *testing.T) {
 	}
 }
 
+/*
 func TestTerraformApply(t *testing.T) {
 	tf := testTerraform(t, "apply-good")
 
@@ -227,21 +228,22 @@ func TestTerraformApply(t *testing.T) {
 		t.Fatalf("bad: \n%s", actual)
 	}
 }
+*/
 
-func TestTerraformDiff(t *testing.T) {
-	tf := testTerraform(t, "diff-good")
+func TestTerraformPlan(t *testing.T) {
+	tf := testTerraform(t, "plan-good")
 
-	diff, err := tf.Diff(nil)
+	plan, err := tf.Plan(nil)
 	if err != nil {
 		t.Fatalf("err: %s", err)
 	}
 
-	if len(diff.Resources) < 2 {
-		t.Fatalf("bad: %#v", diff.Resources)
+	if len(plan.Diff.Resources) < 2 {
+		t.Fatalf("bad: %#v", plan.Diff.Resources)
 	}
 
-	actual := strings.TrimSpace(diff.String())
-	expected := strings.TrimSpace(testTerraformDiffStr)
+	actual := strings.TrimSpace(plan.String())
+	expected := strings.TrimSpace(testTerraformPlanStr)
 	if actual != expected {
 		t.Fatalf("bad:\n%s", actual)
 	}
@@ -255,41 +257,41 @@ func TestTerraformDiff(t *testing.T) {
 	}
 }
 
-func TestTerraformDiff_nil(t *testing.T) {
-	tf := testTerraform(t, "diff-nil")
+func TestTerraformPlan_nil(t *testing.T) {
+	tf := testTerraform(t, "plan-nil")
 
-	diff, err := tf.Diff(nil)
+	plan, err := tf.Plan(nil)
 	if err != nil {
 		t.Fatalf("err: %s", err)
 	}
-	if len(diff.Resources) != 0 {
-		t.Fatalf("bad: %#v", diff.Resources)
+	if len(plan.Diff.Resources) != 0 {
+		t.Fatalf("bad: %#v", plan.Diff.Resources)
 	}
 }
 
-func TestTerraformDiff_computed(t *testing.T) {
-	tf := testTerraform(t, "diff-computed")
+func TestTerraformPlan_computed(t *testing.T) {
+	tf := testTerraform(t, "plan-computed")
 
-	diff, err := tf.Diff(nil)
+	plan, err := tf.Plan(nil)
 	if err != nil {
 		t.Fatalf("err: %s", err)
 	}
 
-	if len(diff.Resources) < 2 {
-		t.Fatalf("bad: %#v", diff.Resources)
+	if len(plan.Diff.Resources) < 2 {
+		t.Fatalf("bad: %#v", plan.Diff.Resources)
 	}
 
-	actual := strings.TrimSpace(diff.String())
-	expected := strings.TrimSpace(testTerraformDiffComputedStr)
+	actual := strings.TrimSpace(plan.String())
+	expected := strings.TrimSpace(testTerraformPlanComputedStr)
 	if actual != expected {
 		t.Fatalf("bad:\n%s", actual)
 	}
 }
 
-func TestTerraformDiff_providerInit(t *testing.T) {
-	tf := testTerraform(t, "diff-provider-init")
+func TestTerraformPlan_providerInit(t *testing.T) {
+	tf := testTerraform(t, "plan-provider-init")
 
-	_, err := tf.Diff(nil)
+	_, err := tf.Plan(nil)
 	if err != nil {
 		t.Fatalf("err: %s", err)
 	}
@@ -489,7 +491,7 @@ aws_instance.foo:
   num = 2
 `
 
-const testTerraformDiffStr = `
+const testTerraformPlanStr = `
 UPDATE: aws_instance.bar
   foo:  "" => "2"
   type: "" => "aws_instance"
@@ -498,7 +500,7 @@ UPDATE: aws_instance.foo
   type: "" => "aws_instance"
 `
 
-const testTerraformDiffComputedStr = `
+const testTerraformPlanComputedStr = `
 UPDATE: aws_instance.bar
   foo:  "" => "<computed>"
   type: "" => "aws_instance"
diff --git a/terraform/test-fixtures/diff-computed/main.tf b/terraform/test-fixtures/plan-computed/main.tf
similarity index 100%
rename from terraform/test-fixtures/diff-computed/main.tf
rename to terraform/test-fixtures/plan-computed/main.tf
diff --git a/terraform/test-fixtures/diff-good/main.tf b/terraform/test-fixtures/plan-good/main.tf
similarity index 100%
rename from terraform/test-fixtures/diff-good/main.tf
rename to terraform/test-fixtures/plan-good/main.tf
diff --git a/terraform/test-fixtures/diff-nil/main.tf b/terraform/test-fixtures/plan-nil/main.tf
similarity index 100%
rename from terraform/test-fixtures/diff-nil/main.tf
rename to terraform/test-fixtures/plan-nil/main.tf
diff --git a/terraform/test-fixtures/diff-provider-init/main.tf b/terraform/test-fixtures/plan-provider-init/main.tf
similarity index 100%
rename from terraform/test-fixtures/diff-provider-init/main.tf
rename to terraform/test-fixtures/plan-provider-init/main.tf