Added test for bootstrap random host selection.

src/main/java/org/qortal/repository/Bootstrap.java

@@ -368,10 +368,7 @@ public class Bootstrap {
     }
 
     private void downloadToPath(Path path) throws DataException {
-        // Select a random host from bootstrapHosts
+        String bootstrapHost = this.getRandomHost();
-        String[] hosts = Settings.getInstance().getBootstrapHosts();
-        int index = new SecureRandom().nextInt(hosts.length);
-        String bootstrapHost = hosts[index];
         String bootstrapFilename = this.getFilename();
         String bootstrapUrl = String.format("%s/%s", bootstrapHost, bootstrapFilename);
 
@@ -420,6 +417,14 @@ public class Bootstrap {
         }
     }
 
+    public String getRandomHost() {
+        // Select a random host from bootstrapHosts
+        String[] hosts = Settings.getInstance().getBootstrapHosts();
+        int index = new SecureRandom().nextInt(hosts.length);
+        String bootstrapHost = hosts[index];
+        return bootstrapHost;
+    }
+
     public void importFromPath(Path path) throws InterruptedException, DataException, IOException {
 
         ReentrantLock blockchainLock = Controller.getInstance().getBlockchainLock();

src/test/java/org/qortal/test/BootstrapTests.java

@@ -22,6 +22,7 @@ import java.nio.file.NoSuchFileException;
 import java.nio.file.Path;
 import java.nio.file.Paths;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.List;
 
 import static org.junit.Assert.*;
@@ -181,6 +182,28 @@ public class BootstrapTests extends Common {
         repository.saveChanges();
     }
 
+    @Test
+    public void testGetRandomHost() {
+        String[] bootstrapHosts = Settings.getInstance().getBootstrapHosts();
+        List<String> uniqueHosts = new ArrayList<>();
+
+        for (int i=0; i<1000; i++) {
+            Bootstrap bootstrap = new Bootstrap();
+            String randomHost = bootstrap.getRandomHost();
+            assertNotNull(randomHost);
+
+            if (!uniqueHosts.contains(randomHost)){
+                uniqueHosts.add(randomHost);
+            }
+        }
+
+        // Ensure we have more than one bootstrap host in the settings
+        assertTrue(Arrays.asList(bootstrapHosts).size() > 1);
+
+        // Ensure that all have been given the opportunity to be used
+        assertEquals(uniqueHosts.size(), Arrays.asList(bootstrapHosts).size());
+    }
+
     private void deleteBootstraps() throws IOException {
         try {
             Path path = Paths.get(String.format("%s%s", Settings.getInstance().getBootstrapFilenamePrefix(), "bootstrap-archive.7z"));