command: validate configuration, test for it

command/apply_test.go

@@ -48,6 +48,24 @@ func TestApply(t *testing.T) {
 	}
 }
 
+func TestApply_configInvalid(t *testing.T) {
+	p := testProvider()
+	ui := new(cli.MockUi)
+	c := &ApplyCommand{
+		TFConfig: testTFConfig(p),
+		Ui:       ui,
+	}
+
+	args := []string{
+		"-init",
+		testTempFile(t),
+		testFixturePath("apply-config-invalid"),
+	}
+	if code := c.Run(args); code != 1 {
+		t.Fatalf("bad: \n%s", ui.OutputWriter.String())
+	}
+}
+
 func TestApply_plan(t *testing.T) {
 	planPath := testPlanFile(t, new(terraform.Plan))
 	statePath := testTempFile(t)

command/command.go

@@ -55,6 +55,9 @@ func PlanArg(
 	if err != nil {
 		return nil, fmt.Errorf("Error loading config: %s", err)
 	}
+	if err := config.Validate(); err != nil {
+		return nil, fmt.Errorf("Error validating config: %s", err)
+	}
 
 	plan, err := tf.Plan(&terraform.PlanOpts{
 		Config: config,

command/test-fixtures/apply-config-invalid/main.tf

@@ -0,0 +1,3 @@
+resource "test_instance" "foo" {
+    ami = "${var.nope}"
+}