Fixes issue with parent field chain for QueryField

force-app/repository/QueryField.cls

@@ -16,7 +16,7 @@ public without sharing virtual class QueryField {
   public QueryField(List<Schema.SObjectField> parentFieldChain, List<Schema.SObjectField> parentFields) {
     String base = '';
     while (parentFieldChain.isEmpty() == false) {
-      base = parentFieldChain.remove(0).getDescribe().getRelationshipName() + '.';
+      base += parentFieldChain.remove(0).getDescribe().getRelationshipName() + '.';
     }
     List<String> fields = new List<String>();
     for (Schema.SObjectField field : parentFields) {

force-app/repository/QueryFieldTests.cls

@@ -0,0 +1,19 @@
+@IsTest
+private class QueryFieldTests {
+  @IsTest
+  static void parentFieldChainsConcatenatedProperly() {
+    QueryField queryField = new QueryField(
+      new List<Schema.SObjectField>{ Contact.AccountId, Account.OwnerId },
+      new List<Schema.SObjectField>{ User.Email }
+    );
+
+    Assert.areEqual('Account.Owner.Email', queryField.toString());
+  }
+
+  @IsTest
+  static void concatenatesFieldsProperly() {
+    QueryField queryField = new QueryField(new List<Schema.SObjectField>{ Contact.AccountId, Contact.LastName });
+
+    Assert.areEqual('AccountId,LastName', queryField.toString());
+  }
+}

force-app/repository/QueryFieldTests.cls-meta.xml

@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<ApexClass xmlns="http://soap.sforce.com/2006/04/metadata">
+    <apiVersion>62.0</apiVersion>
+    <status>Active</status>
+</ApexClass>