Add unplugging test.

tests/mal_unplugging.c

+// This test just plays a constant sine wave tone. Mainly intended to check how physically
+// unplugging a device while it's playing works.
+#define MINI_AL_IMPLEMENTATION
+#include "../mini_al.h"
+#include <stdio.h>
+
+mal_sine_wave g_sineWave;
+mal_event g_stopEvent;
+
+void on_log(mal_context* pContext, mal_device* pDevice, const char* message)
+{
+    (void)pContext;
+    (void)pDevice;
+    printf("%s\n", message);
+}
+
+void on_stop(mal_device* pDevice)
+{
+    (void)pDevice;
+    printf("STOPPED\n");
+    mal_event_signal(&g_stopEvent);
+}
+
+mal_uint32 on_send(mal_device* pDevice, mal_uint32 frameCount, void* pFramesOut)
+{
+    mal_assert(pDevice != NULL);
+    mal_assert(pDevice->channels == 1);
+    (void)pDevice;
+
+    //printf("TESTING: %d\n", frameCount);
+    return (mal_uint32)mal_sine_wave_read(&g_sineWave, frameCount, (float*)pFramesOut);
+}
+
+int main()
+{
+    mal_backend backend = mal_backend_alsa;
+
+    mal_result result = mal_sine_wave_init(0.25f, 400, 48000, &g_sineWave);
+    if (result != MAL_SUCCESS) {
+        printf("Failed to initialize sine wave.\n");
+        return -1;
+    }
+
+    mal_context_config contextConfig = mal_context_config_init(on_log);
+    mal_device_config deviceConfig = mal_device_config_init_playback(mal_format_f32, 1, 48000, on_send);
+    deviceConfig.onStopCallback = on_stop;
+
+    mal_device device;
+    result = mal_device_init_ex(&backend, 1, &contextConfig, mal_device_type_playback, NULL, &deviceConfig, NULL, &device);
+    if (result != MAL_SUCCESS) {
+        return result;
+    }
+
+    mal_event_init(device.pContext, &g_stopEvent);
+
+    result = mal_device_start(&device);
+    if (result != MAL_SUCCESS) {
+        mal_device_uninit(&device);
+        return result;
+    }
+
+
+    printf("Unplug the device...\n");
+    mal_event_wait(&g_stopEvent);
+
+    printf("Plug in the device and hit Enter to attempt to restart the device...\n");
+    getchar();
+
+    // To restart the device, first try mal_device_start(). If it fails, re-initialize from the top.
+    result = mal_device_start(&device);
+    if (result != MAL_SUCCESS) {
+        printf("Failed to restart. Attempting to reinitialize...\n");
+        mal_device_uninit(&device);
+        
+        result = mal_device_init_ex(&backend, 1, &contextConfig, mal_device_type_playback, NULL, &deviceConfig, NULL, &device);
+        if (result != MAL_SUCCESS) {
+            printf("Failed to reinitialize.\n");
+            return -1;
+        }
+
+        result = mal_device_start(&device);
+        if (result != MAL_SUCCESS) {
+            printf("Failed to start device.\n");
+            mal_device_uninit(&device);
+            return -1;
+        }
+    }
+
+    printf("Press Enter to quit...");
+    getchar();
+
+    mal_device_uninit(&device);
+    return 0;
+}
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