Verified SSH credentials plugin by test and example

Fixes #13

demos/credentials/README.md

@@ -44,3 +44,45 @@ we consider the `Impl` suffix as a common pattern to flag implementation class.
 => symbol name is `usernamePassword` 
 
 
+## Examples
+
+A list of some of the more common credentials. 
+
+### SSH Credentials
+
+Example that uses the [SSH credentials plugin](https://plugins.jenkins.io/ssh-credentials)
+
+```yaml
+credentials:
+  system:
+    ? name: "test.com"
+      description: "test.com domain"
+      specifications:
+        - hostnameSpecification:
+            includes:
+              - "*.test.com"
+    : - usernamePassword:
+          scope:    SYSTEM
+          id:       sudo_password
+          username: root
+          password: ${SUDO_PASSWORD}
+    ? # "global"
+      - basicSSHUserPrivateKey:
+          scope: SYSTEM
+          id: ssh_with_passprase
+          username: ssh_root
+          passphrase: ${SSH_KEY_PASSWORD}
+          description: "SSH passphrase with private key file"
+          privateKeySource:
+            fileOnMaster:
+              keyStoreFile: /docker/secret/id_rsa_2
+      - basicSSHUserPrivateKey:
+          scope: SYSTEM
+          id: ssh_with_passprase_provided
+          username: ssh_root
+          passphrase: ${SSH_KEY_PASSWORD}
+          description: "SSH passphrase with private key file. Private key provided"
+          privateKeySource:
+            directEntry:
+              privateKey: ${SSH_PRIVATE_KEY}
+```

src/test/java/org/jenkinsci/plugins/casc/SystemCredentialsTest.java

@@ -1,5 +1,6 @@
 package org.jenkinsci.plugins.casc;
 
+import com.cloudbees.jenkins.plugins.sshcredentials.impl.BasicSSHUserPrivateKey;
 import com.cloudbees.plugins.credentials.CredentialsProvider;
 import com.cloudbees.plugins.credentials.common.CertificateCredentials;
 import com.cloudbees.plugins.credentials.common.UsernamePasswordCredentials;
@@ -26,6 +27,7 @@ public class SystemCredentialsTest {
     public void configure_system_credentials() throws Exception {
         System.setProperty("SUDO_PASSWORD", "1234");
         System.setProperty("SSH_KEY_PASSWORD", "ABCD");
+        System.setProperty("SSH_PRIVATE_KEY", "s3cr3t");
 
         ConfigurationAsCode.configure(getClass().getResourceAsStream("SystemCredentialsTest.yml"));
 
@@ -39,5 +41,11 @@ public void configure_system_credentials() throws Exception {
         final CertificateCredentials cert = certs.get(0);
         assertEquals("ABCD", cert.getPassword().getPlainText());
 
+        List<BasicSSHUserPrivateKey> sshPrivateKeys = CredentialsProvider.lookupCredentials(BasicSSHUserPrivateKey.class, j.jenkins, ACL.SYSTEM, Collections.EMPTY_LIST);
+        assertEquals(2, sshPrivateKeys.size());
+        final BasicSSHUserPrivateKey sshUserPrivateKey = sshPrivateKeys.get(0);
+        assertEquals("ABCD", sshUserPrivateKey.getPassphrase().getPlainText());
+
+
     }
 }

src/test/resources/org/jenkinsci/plugins/casc/SystemCredentialsTest.yml

@@ -19,4 +19,26 @@ credentials:
           keyStoreSource:
             fileOnMaster:
               keyStoreFile: /docker/secret/id_rsa
+      - basicSSHUserPrivateKey:
+          scope: SYSTEM
+          id: ssh_with_passprase
+          username: ssh_root
+          passphrase: ${SSH_KEY_PASSWORD}
+          description: "SSH passphrase with private key file"
+          privateKeySource:
+            fileOnMaster:
+              keyStoreFile: /docker/secret/id_rsa_2
+      - basicSSHUserPrivateKey:
+          scope: SYSTEM
+          id: ssh_with_passprase_provided
+          username: ssh_root
+          passphrase: ${SSH_KEY_PASSWORD}
+          description: "SSH passphrase with private key file. Private key provided"
+          privateKeySource:
+            directEntry:
+              privateKey: ${SSH_PRIVATE_KEY}
+
+
+
+