CTS fix: Signature2Test.test_clone()

Previously it would throw a NullPointerException. Fixing that
rendered the Signature cloneable and the test assertions failing.

The test now passes but is of questionable value except to prove
the absence of RuntimeException.

Change-Id: I2a5b160f0914837b37b801e16b8a3717d00fd94e

2 files changed, 11 insertions, 1 deletions

diff --git a/luni/src/main/java/java/security/Signature.java b/luni/src/main/java/java/security/Signature.java
index 7dd7d93..a39d59b 100644
--- a/luni/src/main/java/java/security/Signature.java
+++ b/luni/src/main/java/java/security/Signature.java
@@ -703,7 +703,7 @@ public abstract class Signature extends SignatureSpi {
 
         @Override
         public Object clone() throws CloneNotSupportedException {
-            SignatureSpi spi = (SignatureSpi) spiImpl.clone();
+            SignatureSpi spi = spiImpl != null ? (SignatureSpi) spiImpl.clone() : null;
             return new SignatureImpl(getAlgorithm(), getProvider(), spi);
         }
 
diff --git a/luni/src/test/java/org/apache/harmony/security/tests/java/security/Signature2Test.java b/luni/src/test/java/org/apache/harmony/security/tests/java/security/Signature2Test.java
index 7886e3e..ad084e1 100644
--- a/luni/src/test/java/org/apache/harmony/security/tests/java/security/Signature2Test.java
+++ b/luni/src/test/java/org/apache/harmony/security/tests/java/security/Signature2Test.java
@@ -68,7 +68,17 @@ public class Signature2Test extends junit.framework.TestCase {
      * java.security.Signature#clone()
      */
     public void test_clone() throws Exception {
+        // A Signature may be cloneable according to the API, in practice the implementation isn't
+        // once it has been initialized. Checking for runtime exceptions rather than useful
+        // behavior.
         Signature s = Signature.getInstance("DSA");
+        Signature clone = (Signature) s.clone();
+        assertNotNull(clone);
+        assertEquals(s.getAlgorithm(), clone.getAlgorithm());
+        assertEquals(s.getProvider(), clone.getProvider());
+
+        KeyPair keyPair = getDsaKeys();
+        s.initSign(keyPair.getPrivate());
         try {
             s.clone();
             fail();