Use internal cache for group names

Author: Art4

src/Redmine/Api/Group.php

@@ -23,6 +23,8 @@ class Group extends AbstractApi
 {
     private $groups = [];
 
+    private $groupNames = null;
+
     /**
      * List groups.
      *
@@ -50,17 +52,17 @@ final public function list(array $params = []): array
      */
     final public function listNames(): array
     {
-        if (empty($this->groups)) {
-            $this->groups = $this->list();
+        if ($this->groupNames !== null) {
+            return $this->groupNames;
         }
 
-        $list = [];
+        $this->groupNames = [];
 
-        foreach ($this->groups['groups'] as $e) {
-            $list[(int) $e['id']] = $e['name'];
+        foreach ($this->list()['groups'] as $group) {
+            $this->groupNames[(int) $group['id']] = $group['name'];
         }
 
-        return $list;
+        return $this->groupNames;
     }
 
     /**

tests/Unit/Api/Group/ListNamesTest.php

@@ -61,4 +61,37 @@ public static function getListNamesData(): array
             ],
         ];
     }
+
+    public function testListNamesCallsHttpClientOnlyOnce()
+    {
+        $client = AssertingHttpClient::create(
+            $this,
+            [
+                'GET',
+                '/groups.json',
+                'application/json',
+                '',
+                200,
+                'application/json',
+                <<<JSON
+                {
+                    "groups": [
+                        {
+                            "id": 1,
+                            "name": "Group 1"
+                        }
+                    ]
+                }
+                JSON,
+            ]
+        );
+
+        // Create the object under test
+        $api = new Group($client);
+
+        // Perform the tests
+        $this->assertSame([1 => 'Group 1'], $api->listNames());
+        $this->assertSame([1 => 'Group 1'], $api->listNames());
+        $this->assertSame([1 => 'Group 1'], $api->listNames());
+    }
 }