AudioDeviceManager: Avoid overwriting user-specified devices in initialise unless absolutely necessary

This fixes an issue where specifying an audio device type before calling
initialise could cause a different device to become active, even if the
requested device type had usable devices.

With this change in place, a new device type will only be selected if
the current device type has no devices.

modules/juce_audio_devices/audio_io/juce_AudioDeviceManager.cpp

@@ -144,6 +144,10 @@ void AudioDeviceManager::pickCurrentDeviceTypeWithDevices()
             || ! ptr->getDeviceNames (false).isEmpty();
     };
 
+    if (auto* type = findType (currentDeviceType))
+        if (deviceTypeHasDevices (type))
+            return;
+
     const auto iter = std::find_if (availableDeviceTypes.begin(),
                                     availableDeviceTypes.end(),
                                     deviceTypeHasDevices);
@@ -1399,6 +1403,32 @@ public:
             expectEquals (newSetup.inputChannels.countNumberOfSetBits(), 2);
         }
 
+        beginTest ("If a device type has been explicitly set to a type with devices, "
+                   "initialisation should respect this choice");
+        {
+            AudioDeviceManager manager;
+            initialiseManagerWithEmptyDeviceType (manager);
+            manager.setCurrentAudioDeviceType (mockBName, true);
+
+            AudioDeviceManager::AudioDeviceSetup setup;
+            expect (manager.initialise (2, 2, nullptr, true, {}, &setup).isEmpty());
+
+            expectEquals (manager.getCurrentAudioDeviceType(), mockBName);
+        }
+
+        beginTest ("If a device type has been explicitly set to a type without devices, "
+                   "initialisation should pick a type with devices instead");
+        {
+            AudioDeviceManager manager;
+            initialiseManagerWithEmptyDeviceType (manager);
+            manager.setCurrentAudioDeviceType (emptyName, true);
+
+            AudioDeviceManager::AudioDeviceSetup setup;
+            expect (manager.initialise (2, 2, nullptr, true, {}, &setup).isEmpty());
+
+            expectEquals (manager.getCurrentAudioDeviceType(), mockAName);
+        }
+
         beginTest ("Carry out a long sequence of configuration changes");
         {
             AudioDeviceManager manager;