fix(auth): Fix incorrect import of partial user metadata. (#445)

* Fix incorrect import of partial user metadata.

* Remove validating metadata for null.

Author: valery-barysok

auth/import_users.go

@@ -143,8 +143,15 @@ func (u *UserToImport) PhoneNumber(phoneNumber string) *UserToImport {
 
 // Metadata setter.
 func (u *UserToImport) Metadata(metadata *UserMetadata) *UserToImport {
-	u.set("createdAt", metadata.CreationTimestamp)
-	return u.set("lastLoginAt", metadata.LastLogInTimestamp)
+	if metadata.CreationTimestamp != 0 {
+		u.set("createdAt", metadata.CreationTimestamp)
+	}
+
+	if metadata.LastLogInTimestamp != 0 {
+		u.set("lastLoginAt", metadata.LastLogInTimestamp)
+	}
+
+	return u
 }
 
 // CustomClaims setter.

auth/user_mgt_test.go

@@ -1184,6 +1184,24 @@ func TestUserToImport(t *testing.T) {
 				"lastLoginAt": int64(150),
 			},
 		},
+		{
+			user: (&UserToImport{}).UID("test").Metadata(&UserMetadata{
+				CreationTimestamp: int64(100),
+			}),
+			want: map[string]interface{}{
+				"localId":   "test",
+				"createdAt": int64(100),
+			},
+		},
+		{
+			user: (&UserToImport{}).UID("test").Metadata(&UserMetadata{
+				LastLogInTimestamp: int64(150),
+			}),
+			want: map[string]interface{}{
+				"localId":     "test",
+				"lastLoginAt": int64(150),
+			},
+		},
 		{
 			user: (&UserToImport{}).UID("test").PasswordHash([]byte("password")),
 			want: map[string]interface{}{