add public testnet electrum server

src/main/java/com/sparrowwallet/sparrow/MainApp.java

@@ -77,7 +77,8 @@ public class MainApp extends Application {
                     createNewWallet = optNewWallet.isPresent() && optNewWallet.get();
                 } else if(Network.get() == Network.MAINNET) {
                     Config.get().setServerType(ServerType.PUBLIC_ELECTRUM_SERVER);
-                    Config.get().setPublicElectrumServer(PublicElectrumServer.values()[new Random().nextInt(PublicElectrumServer.values().length)].getUrl());
+                    List<PublicElectrumServer> servers = PublicElectrumServer.getServers();
+                    Config.get().setPublicElectrumServer(servers.get(new Random().nextInt(servers.size())).getUrl());
                 }
             }
         }

src/main/java/com/sparrowwallet/sparrow/io/Config.java

@@ -384,7 +384,7 @@ public class Config {
     }
 
     public void changePublicServer() {
-        List<String> otherServers = Arrays.stream(PublicElectrumServer.values()).map(PublicElectrumServer::getUrl).filter(url -> !url.equals(getPublicElectrumServer())).collect(Collectors.toList());
+        List<String> otherServers = PublicElectrumServer.getServers().stream().map(PublicElectrumServer::getUrl).filter(url -> !url.equals(getPublicElectrumServer())).collect(Collectors.toList());
         setPublicElectrumServer(otherServers.get(new Random().nextInt(otherServers.size())));
     }
 

src/main/java/com/sparrowwallet/sparrow/net/PublicElectrumServer.java

@@ -1,19 +1,30 @@
 package com.sparrowwallet.sparrow.net;
 
-public enum PublicElectrumServer {
+import com.sparrowwallet.drongo.Network;
-    BLOCKSTREAM_INFO("blockstream.info", "ssl://blockstream.info:700"),
-    ELECTRUM_BLOCKSTREAM_INFO("electrum.blockstream.info", "ssl://electrum.blockstream.info:50002"),
-    LUKECHILDS_CO("bitcoin.lukechilds.co", "ssl://bitcoin.lukechilds.co:50002"),
-    EMZY_DE("electrum.emzy.de", "ssl://electrum.emzy.de:50002"),
-    BITAROO_NET("electrum.bitaroo.net", "ssl://electrum.bitaroo.net:50002");
 
-    PublicElectrumServer(String name, String url) {
+import java.util.Arrays;
+import java.util.List;
+import java.util.stream.Collectors;
+
+public enum PublicElectrumServer {
+    BLOCKSTREAM_INFO("blockstream.info", "ssl://blockstream.info:700", Network.MAINNET),
+    ELECTRUM_BLOCKSTREAM_INFO("electrum.blockstream.info", "ssl://electrum.blockstream.info:50002", Network.MAINNET),
+    LUKECHILDS_CO("bitcoin.lukechilds.co", "ssl://bitcoin.lukechilds.co:50002", Network.MAINNET),
+    EMZY_DE("electrum.emzy.de", "ssl://electrum.emzy.de:50002", Network.MAINNET),
+    BITAROO_NET("electrum.bitaroo.net", "ssl://electrum.bitaroo.net:50002", Network.MAINNET),
+    TESTNET_ARANGUREN_ORG("testnet.aranguren.org", "ssl://testnet.aranguren.org:51002", Network.TESTNET);
+
+    PublicElectrumServer(String name, String url, Network network) {
         this.name = name;
         this.url = url;
+        this.network = network;
     }
 
+    public static final List<Network> SUPPORTED_NETWORKS = List.of(Network.MAINNET, Network.TESTNET);
+
     private final String name;
     private final String url;
+    private final Network network;
 
     public String getName() {
         return name;
@@ -23,6 +34,18 @@ public enum PublicElectrumServer {
         return url;
     }
 
+    public Network getNetwork() {
+        return network;
+    }
+
+    public static List<PublicElectrumServer> getServers() {
+        return Arrays.stream(values()).filter(server -> server.network == Network.get()).collect(Collectors.toList());
+    }
+
+    public static boolean supportedNetwork() {
+        return SUPPORTED_NETWORKS.contains(Network.get());
+    }
+
     public static PublicElectrumServer fromUrl(String url) {
         for(PublicElectrumServer server : values()) {
             if(server.url.equals(url)) {

src/main/java/com/sparrowwallet/sparrow/preferences/ServerPreferencesController.java

@@ -15,6 +15,7 @@ import com.sparrowwallet.sparrow.io.Storage;
 import com.sparrowwallet.sparrow.net.*;
 import javafx.application.Platform;
 import javafx.beans.value.ChangeListener;
+import javafx.collections.FXCollections;
 import javafx.fxml.FXML;
 import javafx.scene.control.*;
 import javafx.scene.text.Font;
@@ -186,15 +187,16 @@ public class ServerPreferencesController extends PreferencesDetailController {
             }
         });
         ServerType serverType = config.getServerType() != null ?
-                (config.getServerType() == ServerType.PUBLIC_ELECTRUM_SERVER && Network.get() != Network.MAINNET ? ServerType.BITCOIN_CORE : config.getServerType()) :
+                (config.getServerType() == ServerType.PUBLIC_ELECTRUM_SERVER && !PublicElectrumServer.supportedNetwork() ? ServerType.BITCOIN_CORE : config.getServerType()) :
                     (config.getCoreServer() == null && config.getElectrumServer() != null ? ServerType.ELECTRUM_SERVER :
-                        (config.getCoreServer() != null || Network.get() != Network.MAINNET ? ServerType.BITCOIN_CORE : ServerType.PUBLIC_ELECTRUM_SERVER));
+                        (config.getCoreServer() != null || !PublicElectrumServer.supportedNetwork() ? ServerType.BITCOIN_CORE : ServerType.PUBLIC_ELECTRUM_SERVER));
-        if(Network.get() != Network.MAINNET) {
+        if(!PublicElectrumServer.supportedNetwork()) {
             serverTypeSegmentedButton.getButtons().remove(publicElectrumToggle);
             serverTypeToggleGroup.getToggles().remove(publicElectrumToggle);
         }
         serverTypeToggleGroup.selectToggle(serverTypeToggleGroup.getToggles().stream().filter(toggle -> toggle.getUserData() == serverType).findFirst().orElse(null));
 
+        publicElectrumServer.setItems(FXCollections.observableList(PublicElectrumServer.getServers()));
         publicElectrumServer.getSelectionModel().selectedItemProperty().addListener(getPublicElectrumServerListener(config));
 
         publicUseProxy.selectedProperty().bindBidirectional(useProxy.selectedProperty());
@@ -326,7 +328,8 @@ public class ServerPreferencesController extends PreferencesDetailController {
 
         PublicElectrumServer configPublicElectrumServer = PublicElectrumServer.fromUrl(config.getPublicElectrumServer());
         if(configPublicElectrumServer == null) {
-            publicElectrumServer.setValue(PublicElectrumServer.values()[new Random().nextInt(PublicElectrumServer.values().length)]);
+            List<PublicElectrumServer> servers = PublicElectrumServer.getServers();
+            publicElectrumServer.setValue(servers.get(new Random().nextInt(servers.size())));
         } else {
             publicElectrumServer.setValue(configPublicElectrumServer);
         }

src/main/resources/com/sparrowwallet/sparrow/preferences/server.fxml

@@ -85,17 +85,7 @@
                 <CopyableLabel text="Using a public server means it can see your transactions."/>
             </Field>
             <Field text="URL:">
-                <ComboBox fx:id="publicElectrumServer">
+                <ComboBox fx:id="publicElectrumServer" />
-                    <items>
-                        <FXCollections fx:factory="observableArrayList">
-                            <PublicElectrumServer fx:constant="BLOCKSTREAM_INFO" />
-                            <PublicElectrumServer fx:constant="ELECTRUM_BLOCKSTREAM_INFO" />
-                            <PublicElectrumServer fx:constant="LUKECHILDS_CO" />
-                            <PublicElectrumServer fx:constant="EMZY_DE" />
-                            <PublicElectrumServer fx:constant="BITAROO_NET" />
-                        </FXCollections>
-                    </items>
-                </ComboBox>
             </Field>
             <Field text="Use Proxy:">
                 <UnlabeledToggleSwitch fx:id="publicUseProxy"/>