From 533b8b8b5f499ac06a54baf48be55b72ee3bef0f Mon Sep 17 00:00:00 2001
From: Ben Roberts <beroberts@wayfair.com>
Date: Tue, 21 Nov 2017 12:18:28 -0500
Subject: [PATCH] testDetectsAdditionsToUnionType

---
 src/Utils/FindBreakingChanges.php       |  7 +--
 tests/Utils/FindBreakingChangesTest.php | 59 +++++++++++++++++++++++++
 2 files changed, 63 insertions(+), 3 deletions(-)

diff --git a/src/Utils/FindBreakingChanges.php b/src/Utils/FindBreakingChanges.php
index 3880dcb..c747a71 100644
--- a/src/Utils/FindBreakingChanges.php
+++ b/src/Utils/FindBreakingChanges.php
@@ -433,12 +433,13 @@ class FindBreakingChanges
         Schema $oldSchema, Schema $newSchema
     )
     {
+        $oldTypeMap = $oldSchema->getTypeMap();
         $newTypeMap = $newSchema->getTypeMap();
 
         $typesAddedToUnion = [];
 
-        foreach ($newTypeMap as $typeName => $oldType) {
-            $newType = isset($newTypeMap[$typeName]) ? $newTypeMap[$typeName] : null;
+        foreach ($newTypeMap as $typeName => $newType) {
+            $oldType = isset($oldTypeMap[$typeName]) ? $oldTypeMap[$typeName] : null;
             if (!($oldType instanceof UnionType) || !($newType instanceof UnionType)) {
                 continue;
             }
@@ -450,7 +451,7 @@ class FindBreakingChanges
             foreach ($newType->getTypes() as $type) {
                 if (!isset($typeNamesInOldUnion[$type->name])) {
                     $addedTypeName = $type->name;
-                    $typesRemovedFromUnion[] = ['type' => self::DANGEROUS_CHANGE_TYPE_ADDED_TO_UNION, 'description' => "${addedTypeName} was removed to union type ${typeName}"];
+                    $typesAddedToUnion[] = ['type' => self::DANGEROUS_CHANGE_TYPE_ADDED_TO_UNION, 'description' => "${addedTypeName} was added to union type ${typeName}"];
                 }
             }
         }
diff --git a/tests/Utils/FindBreakingChangesTest.php b/tests/Utils/FindBreakingChangesTest.php
index a15b093..0d461f4 100644
--- a/tests/Utils/FindBreakingChangesTest.php
+++ b/tests/Utils/FindBreakingChangesTest.php
@@ -1326,4 +1326,63 @@ class FindBreakingChangesTest extends \PHPUnit_Framework_TestCase
             FindBreakingChanges::findValuesAddedToEnums($oldSchema, $newSchema)[0]
         );
     }
+
+    public function testDetectsAdditionsToUnionType() {
+        $type1 = new ObjectType([
+            'name' => 'Type1',
+            'fields' => [
+                'field1' => Type::string()
+            ]
+        ]);
+
+        $type1a = new ObjectType([
+            'name' => 'Type1',
+            'fields' => [
+                'field1' => Type::string()
+            ]
+        ]);
+
+        $type2 = new ObjectType([
+            'name' => 'Type2',
+            'fields' => [
+                'field1' => Type::string()
+            ]
+        ]);
+
+        $oldUnionType = new UnionType([
+            'name' => 'UnionType1',
+            'types' => [$type1],
+            'resolveType' => function () {
+            }
+        ]);
+
+        $newUnionType = new UnionType([
+            'name' => 'UnionType1',
+            'types' => [$type1a, $type2],
+            'resolveType' => function () {
+            }
+        ]);
+
+        $oldSchema = new Schema([
+            'query' => $this->queryType,
+            'types' => [
+                $oldUnionType
+            ]
+        ]);
+
+        $newSchema = new Schema([
+            'query' => $this->queryType,
+            'types' => [
+                $newUnionType
+            ]
+        ]);
+
+        $this->assertEquals(
+            [
+               'type' => FindBreakingChanges::DANGEROUS_CHANGE_TYPE_ADDED_TO_UNION,
+               'description' => 'Type2 was added to union type UnionType1'
+            ],
+            FindBreakingChanges::findTypesAddedToUnions($oldSchema, $newSchema)[0]
+        );
+    }
 }
\ No newline at end of file