config: LoadDir with no matching files errors

config/loader.go

@@ -1,6 +1,7 @@
 package config
 
 import (
+	"fmt"
 	"path/filepath"
 )
 
@@ -35,6 +36,12 @@ func LoadDir(path string) (*Config, error) {
 		return nil, err
 	}
 
+	if len(matches) == 0 {
+		return nil, fmt.Errorf(
+			"No Terraform configuration files found in directory: %s",
+			path)
+	}
+
 	var result *Config
 	for _, f := range matches {
 		c, err := Load(f)

config/loader_test.go

@@ -128,6 +128,13 @@ func TestLoadDir_basic(t *testing.T) {
 	}
 }
 
+func TestLoadDir_noConfigs(t *testing.T) {
+	_, err := LoadDir(filepath.Join(fixtureDir, "dir-empty"))
+	if err == nil {
+		t.Fatal("should error")
+	}
+}
+
 func outputsStr(os map[string]*Output) string {
 	ns := make([]string, 0, len(os))
 	for n, _ := range os {