core: basic test of EvalVariableBlock

This previously lacked tests altogether. This new test verifies the
"happy path", ensuring that both literal and computed values pass through
correctly into the VariableValues map.

terraform/eval_variable.go

@@ -114,7 +114,6 @@ type EvalVariableBlock struct {
 	VariableValues map[string]interface{}
 }
 
-// TODO: test
 func (n *EvalVariableBlock) Eval(ctx EvalContext) (interface{}, error) {
 	// Clear out the existing mapping
 	for k, _ := range n.VariableValues {

terraform/eval_variable_test.go

@@ -3,6 +3,8 @@ package terraform
 import (
 	"reflect"
 	"testing"
+
+	"github.com/hashicorp/terraform/config"
 )
 
 func TestCoerceMapVariable(t *testing.T) {
@@ -140,3 +142,78 @@ func TestCoerceMapVariable(t *testing.T) {
 		}
 	}
 }
+
+func TestEvalVariableBlock(t *testing.T) {
+	rc, err := config.NewRawConfig(map[string]interface{}{
+		"known":      "foo",
+		"known_list": []interface{}{"foo"},
+		"known_map": map[string]interface{}{
+			"foo": "foo",
+		},
+		"known_list_of_maps": []map[string]interface{}{
+			map[string]interface{}{
+				"foo": "foo",
+			},
+		},
+		"computed_map": map[string]interface{}{},
+		"computed_list_of_maps": []map[string]interface{}{
+			map[string]interface{}{},
+		},
+		// No computed_list right now, because that isn't currently supported:
+		// EvalVariableBlock assumes the final step of the path will always
+		// be a map.
+	})
+	if err != nil {
+		t.Fatalf("config.NewRawConfig failed: %s", err)
+	}
+
+	cfg := NewResourceConfig(rc)
+	cfg.ComputedKeys = []string{
+		"computed",
+		"computed_map.foo",
+		"computed_list_of_maps.0.foo",
+	}
+
+	n := &EvalVariableBlock{
+		VariableValues: map[string]interface{}{
+			// Should be cleared out on Eval
+			"should_be_deleted": true,
+		},
+		Config: &cfg,
+	}
+
+	ctx := &MockEvalContext{}
+	val, err := n.Eval(ctx)
+	if err != nil {
+		t.Fatalf("n.Eval failed: %s", err)
+	}
+	if val != nil {
+		t.Fatalf("n.Eval returned non-nil result: %#v", val)
+	}
+
+	got := n.VariableValues
+	want := map[string]interface{}{
+		"known":      "foo",
+		"known_list": []interface{}{"foo"},
+		"known_map": map[string]interface{}{
+			"foo": "foo",
+		},
+		"known_list_of_maps": []interface{}{
+			map[string]interface{}{
+				"foo": "foo",
+			},
+		},
+		"computed": config.UnknownVariableValue,
+		"computed_map": map[string]interface{}{
+			"foo": config.UnknownVariableValue,
+		},
+		"computed_list_of_maps": []interface{}{
+			map[string]interface{}{
+				"foo": config.UnknownVariableValue,
+			},
+		},
+	}
+	if !reflect.DeepEqual(got, want) {
+		t.Errorf("Incorrect variables\ngot:  %#v\nwant: %#v", got, want)
+	}
+}