fix: String method on the OptionalString (ipfs#153)

* fix: String method on the OptionalString
* test(OptionalString): empty string is preserved

Co-authored-by: Marcin Rataj <lidel@lidel.org>

config/types.go

@@ -360,7 +360,7 @@ func (p OptionalString) String() string {
  if p.value == nil {
  return "default"
  }
- return fmt.Sprintf("%d", p.value)
+ return *p.value
 }
 
 var _ json.Unmarshaler = (*OptionalInteger)(nil)

config/types_test.go

@@ -407,11 +407,13 @@ func TestOptionalString(t *testing.T) {
  t.Fatal("should be the default")
  }
  if val := defaultOptionalString.WithDefault(""); val != "" {
- t.Errorf("optional integer should have been empty, got %s", val)
+ t.Errorf("optional string should have been empty, got %s", val)
+ }
+ if val := defaultOptionalString.String(); val != "default" {
+ t.Fatalf("default optional string should be the 'default' string, got %s", val)
  }
-
  if val := defaultOptionalString.WithDefault("foo"); val != "foo" {
- t.Errorf("optional integer should have been foo, got %s", val)
+ t.Errorf("optional string should have been foo, got %s", val)
  }
 
  var filledStr OptionalString
@@ -420,17 +422,20 @@ func TestOptionalString(t *testing.T) {
  t.Fatal("should not be the default")
  }
  if val := filledStr.WithDefault("bar"); val != "foo" {
- t.Errorf("optional integer should have been foo, got %s", val)
+ t.Errorf("optional string should have been foo, got %s", val)
+ }
+ if val := filledStr.String(); val != "foo" {
+ t.Fatalf("optional string should have been foo, got %s", val)
  }
-
  filledStr = OptionalString{value: makeStringPointer("")}
  if val := filledStr.WithDefault("foo"); val != "" {
- t.Errorf("optional integer should have been 0, got %s", val)
+ t.Errorf("optional string should have been 0, got %s", val)
  }
 
  for jsonStr, goValue := range map[string]OptionalString{
  "null": {},
  "\"0\"": {value: makeStringPointer("0")},
+ "\"\"": {value: makeStringPointer("")},
  `"1"`: {value: makeStringPointer("1")},
  `"-1"`: {value: makeStringPointer("-1")},
  `"qwerty"`: {value: makeStringPointer("qwerty")},