MainWindow.gd

@@ -174,6 +174,7 @@ func _ready() -> void:
 	music_player_container.connect("play_next_song", play_next_song)
 	music_player_container.connect("update_song_list", update_song_list)
 	settings_window.connect("server_changed", server_updated)
+	settings_window.visibility_changed.connect(_on_settings_window_visibility_changed)
 	sync_window.connect("sync_started", _on_sync_started)
 	sync_window.connect("sync_finished", _on_sync_finished)
 	
@@ -277,6 +278,12 @@ func play_next_song() -> void:
 #"/music/rand"
 #"/music/addQue"
 #"/music/info"
+# The cache size can be changed in the settings. Waiting until the settings are closed
+# avoids starting downloads while the user is still clicking the number up and down.
+func _on_settings_window_visibility_changed() -> void:
+	if !settings_window.visible && !Playlist.is_song_downloading && Playlist.should_preload_more_songs():
+		fetch_song()
+
 func fetch_song() -> void:
 	print("fetch_song")
 	Playlist.is_song_downloading = true

tests/integration/test_main_window.gd

@@ -158,3 +158,59 @@ func test_cache_keeps_filling_after_a_failed_download() -> void:
 
     assert_int(Playlist.get_preloaded_songs()).is_equal(3)
     assert_bool(Playlist.is_song_downloading).is_false()
+
+
+func _open_settings() -> void:
+    _press("SettingsButton")
+
+
+func _close_settings() -> void:
+    (_window.get_node("SettingsWindow") as Control).visible = false
+
+
+func _press_settings_button(unique_name: String) -> void:
+    (_window.get_node("SettingsWindow").get_node("%" + unique_name) as Button).pressed.emit()
+
+
+func test_raising_cache_size_does_not_download_while_settings_are_open() -> void:
+    var downloads_before: int = _server.count("/music/rand")
+    _open_settings()
+
+    _press_settings_button("IncreaseCacheButton")
+    _press_settings_button("IncreaseCacheButton")
+
+    assert_int(Playlist.number_of_tracks_to_preload).is_equal(3)
+    assert_int(_server.count("/music/rand")).is_equal(downloads_before)
+
+
+func test_closing_settings_fills_cache_to_new_size() -> void:
+    _open_settings()
+    _press_settings_button("IncreaseCacheButton")
+    _press_settings_button("IncreaseCacheButton")
+
+    _close_settings()
+
+    assert_int(Playlist.get_preloaded_songs()).is_equal(3)
+
+
+func test_changing_cache_size_back_and_forth_downloads_only_what_is_needed() -> void:
+    var downloads_before: int = _server.count("/music/rand")
+    _open_settings()
+    for i: int in 5:
+        _press_settings_button("IncreaseCacheButton")
+        _press_settings_button("LowerCacheButton")
+    _press_settings_button("IncreaseCacheButton")
+
+    _close_settings()
+
+    assert_int(_server.count("/music/rand") - downloads_before).is_equal(1)
+    assert_int(Playlist.get_preloaded_songs()).is_equal(2)
+
+
+func test_closing_settings_with_full_cache_downloads_nothing() -> void:
+    var downloads_before: int = _server.count("/music/rand")
+    _open_settings()
+
+    _close_settings()
+
+    assert_int(_server.count("/music/rand")).is_equal(downloads_before)