Test host verifiers with a randomly selected ssh provider

The bitbucket.org ssh provider seems to be blocking access from the
ci.jenkins.io agents.  That causes tests to fail. Use other ssh providers.

Reduce the load on ssh providers by only testing one in ten times.
Spread the load by using a randomly selected ssh provider instead of
always using the same ssh provider.

(cherry picked from commit 58b1b7b)

Author: MarkEWaite

src/test/java/org/jenkinsci/plugins/gitclient/verifier/KnownHostsFileVerifierTest.java

@@ -2,7 +2,7 @@
 
 import static org.hamcrest.MatcherAssert.assertThat;
 import static org.hamcrest.Matchers.is;
-import static org.jenkinsci.plugins.gitclient.verifier.KnownHostsTestUtil.isKubernetesCI;
+import static org.jenkinsci.plugins.gitclient.verifier.KnownHostsTestUtil.nonGitHubHost;
 import static org.mockito.Mockito.spy;
 import static org.mockito.Mockito.when;
 
@@ -11,7 +11,9 @@
 import java.io.File;
 import java.io.IOException;
 import java.time.Duration;
+import java.util.concurrent.ThreadLocalRandom;
 import org.awaitility.Awaitility;
+import org.junit.Assume;
 import org.junit.Before;
 import org.junit.Rule;
 import org.junit.Test;
@@ -45,12 +47,14 @@ public void assignVerifiers() throws IOException {
 
     @Test
     public void connectWhenHostKeyNotInKnownHostsFileForOtherHostNameThenShouldFail() throws Exception {
+        // Only test 10% of the time to reduce load on ssh providers
+        Assume.assumeTrue(ThreadLocalRandom.current().nextInt(10) == 0);
         fakeKnownHosts = knownHostsTestUtil.createFakeKnownHosts("fake2.ssh", "known_hosts_fake2", FILE_CONTENT);
         KnownHostsFileVerifier knownHostsFileVerifier = spy(new KnownHostsFileVerifier());
         when(knownHostsFileVerifier.getKnownHostsFile()).thenReturn(fakeKnownHosts);
 
         KnownHostsTestUtil.connectToHost(
-                        "bitbucket.org",
+                        nonGitHubHost(),
                         22,
                         fakeKnownHosts,
                         knownHostsFileVerifier.forJGit(StreamBuildListener.fromStdout()),

src/test/java/org/jenkinsci/plugins/gitclient/verifier/KnownHostsTestUtil.java

@@ -17,6 +17,7 @@
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Objects;
+import java.util.concurrent.ThreadLocalRandom;
 import java.util.function.Predicate;
 import org.apache.sshd.client.ClientBuilder;
 import org.apache.sshd.client.SshClient;
@@ -135,14 +136,20 @@ protected static boolean checkKeys(JGitClientSession s) {
         return verified;
     }
 
-    /* Return true if running on a Kubernetes pod on ci.jenkins.io */
+    // Several different git providers with ssh access, use one randomly
+    private static String[] nonGitHubHosts = {
+        // bitbucket.org blocks requests from ci.jenkins.io agents
+        // "bitbucket.org",
+        "git.assembla.com", "gitea.com", "gitlab.com", "vs-ssh.visualstudio.com",
+    };
+
+    /* Return hostname of a non-GitHub ssh provider */
+    public static String nonGitHubHost() {
+        return nonGitHubHosts[ThreadLocalRandom.current().nextInt(nonGitHubHosts.length)];
+    }
+
+    /* Always return false, retained for test compatibility */
     public static boolean isKubernetesCI() {
         return false;
-        //        String kubernetesPort = System.getenv("KUBERNETES_PORT");
-        //        String buildURL = System.getenv("BUILD_URL");
-        //        return kubernetesPort != null
-        //                && !kubernetesPort.isEmpty()
-        //                && buildURL != null
-        //                && buildURL.startsWith("https://ci.jenkins.io/");
     }
 }

src/test/java/org/jenkinsci/plugins/gitclient/verifier/ManuallyProvidedKeyVerifierTest.java

@@ -2,7 +2,7 @@
 
 import static org.hamcrest.MatcherAssert.assertThat;
 import static org.hamcrest.Matchers.is;
-import static org.jenkinsci.plugins.gitclient.verifier.KnownHostsTestUtil.isKubernetesCI;
+import static org.jenkinsci.plugins.gitclient.verifier.KnownHostsTestUtil.nonGitHubHost;
 
 import hudson.model.StreamBuildListener;
 import hudson.model.TaskListener;
@@ -13,7 +13,9 @@
 import java.nio.file.Path;
 import java.time.Duration;
 import java.util.Collections;
+import java.util.concurrent.ThreadLocalRandom;
 import org.awaitility.Awaitility;
+import org.junit.Assume;
 import org.junit.Before;
 import org.junit.Rule;
 import org.junit.Test;
@@ -32,17 +34,19 @@ public class ManuallyProvidedKeyVerifierTest {
     private String hostKey;
 
     @Before
-    public void assignVerifier() {
+    public void assignVerifier() { // For github.com
         hostKey =
                 "|1|7qEjynZk0IodegnbgoPEhWtdgA8=|bGs7a1ktbGWwPuZqqTbAazUAULM= ecdsa-sha2-nistp256 AAAAE2VjZHNhLXNoYTItbmlzdHAyNTYAAAAIbmlzdHAyNTYAAABBBEmKSENjQEezOmxkZMy7opKgwFB9nkt5YRrYMjNuG5N87uRgg6CLrbo5wAdT/y6v0mKV0U2w0WZ2YB/++Tpockg=";
     }
 
     @Test
     public void connectWhenHostKeyProvidedForOtherHostNameThenShouldFail() throws Exception {
+        // Only test 10% of the time to reduce load on ssh providers
+        Assume.assumeTrue(ThreadLocalRandom.current().nextInt(10) == 0);
         HostKeyVerifierFactory verifier = new ManuallyProvidedKeyVerifier(hostKey);
 
         KnownHostsTestUtil.connectToHost(
-                        "bitbucket.org",
+                        nonGitHubHost(),
                         22,
                         new File(testFolder.getRoot() + "/path/to/file/random"),
                         verifier.forJGit(StreamBuildListener.fromStdout()),