helper/config: can validate array configurations

helper/config/validator.go

@@ -84,6 +84,8 @@ func (v *Validator) Validate(
 }
 
 type validatorKey interface {
+	// Validate validates the given configuration and returns viewed keys,
+	// warnings, and errors.
 	Validate(map[string]string) ([]string, []string, []error)
 }
 
@@ -179,9 +181,11 @@ func (v *nestedValidatorKey) Validate(
 		}
 
 		for k, _ := range m {
+			if k != prefix[:len(prefix)-1] {
 				if !strings.HasPrefix(k, prefix) {
 					continue
 				}
+			}
 
 			used = append(used, k)
 		}

helper/config/validator_test.go

@@ -43,6 +43,31 @@ func TestValidator(t *testing.T) {
 	testInvalid(v, c)
 }
 
+func TestValidator_array(t *testing.T) {
+	v := &Validator{
+		Required: []string{
+			"foo",
+			"nested.*",
+		},
+	}
+
+	var c *terraform.ResourceConfig
+
+	// Valid
+	c = testConfig(t, map[string]interface{}{
+		"foo":    "bar",
+		"nested": []string{"foo", "bar"},
+	})
+	testValid(v, c)
+
+	// Not a nested structure
+	c = testConfig(t, map[string]interface{}{
+		"foo":    "bar",
+		"nested": "baa",
+	})
+	testInvalid(v, c)
+}
+
 func TestValidator_complex(t *testing.T) {
 	v := &Validator{
 		Required: []string{