add affirmative test case for #4762

builder/amazon/common/ami_config.go

@@ -73,8 +73,8 @@ func (c *AMIConfig) Prepare(ctx *interpolate.Context) []error {
 		errs = append(errs, fmt.Errorf("AMIName must be between 3 and 128 characters long"))
 	}
 
-	var IsValidName = regexp.MustCompile(`^[a-zA-Z().-/_]+$`).MatchString
-	if !IsValidName(c.AMIName) {
+	amiNameRe := regexp.MustCompile(`^[a-zA-Z().\-/_]+$`)
+	if !amiNameRe.MatchString(c.AMIName) {
 		errs = append(errs, fmt.Errorf("AMIName should only contain letters, numbers, '(', ')', '.', '-', '/' and '_'"))
 	}
 

builder/amazon/common/ami_config_test.go

@@ -96,4 +96,10 @@ func TestAMINameValidation(t *testing.T) {
 	if err := c.Prepare(nil); err == nil {
 		t.Fatal("shouldn't be able to have an ami name with invalid characters")
 	}
+
+	c.AMIName = "foo().-/_bar"
+	if err := c.Prepare(nil); err != nil {
+		t.Fatal("expected 'foobar' to be a valid ami name")
+	}
+
 }