For #9935 - Use the searchengine deferred

app/src/main/java/org/mozilla/fenix/components/searchengine/FenixSearchEngineProvider.kt

@@ -61,7 +61,8 @@ open class FenixSearchEngineProvider(
     private val fallBackProvider =
         AssetsSearchEngineProvider(fallbackLocationService)
 
-    private val fallbackEngines = async { fallBackProvider.loadSearchEngines(context) }
+    @VisibleForTesting(otherwise = VisibleForTesting.PRIVATE)
+    open val fallbackEngines = async { fallBackProvider.loadSearchEngines(context) }
     private val fallbackRegion = async { fallbackLocationService.determineRegion() }
 
     @VisibleForTesting(otherwise = VisibleForTesting.PRIVATE)
@@ -213,7 +214,11 @@ open class FenixSearchEngineProvider(
         }
 
         if (!prefs.contains(installedEnginesKey)) {
-            val defaultSet = baseSearchEngines.await()
+            val searchEngines =
+                if (baseSearchEngines.isCompleted) baseSearchEngines
+                else fallbackEngines
+
+            val defaultSet = searchEngines.await()
                 .list
                 .map { it.identifier }
                 .toSet()

app/src/test/java/org/mozilla/fenix/components/searchengine/FenixSearchEngineProviderTest.kt

@@ -119,6 +119,21 @@ class FakeFenixSearchEngineProvider(context: Context) : FenixSearchEngineProvide
             )
         }
 
+    override val fallbackEngines: Deferred<SearchEngineList>
+        get() {
+            val google = mockSearchEngine(id = "google-b-1-m", n = "Google")
+
+            return CompletableDeferred(
+                SearchEngineList(
+                    listOf(
+                        google,
+                        mockSearchEngine("bing", "Bing"),
+                        mockSearchEngine("amazondotcom", "Amazon.com")
+                    ), default = google
+                )
+            )
+        }
+
     override val bundledSearchEngines = CompletableDeferred(
         SearchEngineList(
             listOf(