add test: ReadOnlyFieldTest

src/main/java/component/SignatureInfo.java

@@ -17,11 +17,18 @@ public class SignatureInfo implements TlvComponentBase, IEncodingAble {
     private SignatureType signatureType;
     private KeyLocator keyLocator;
 
+    public SignatureInfo(){
+        signatureType=new SignatureType();
+        keyLocator=new KeyLocator();
+    }
+
     /**
      * 根据签名值类型创建一个 SignatureInfo
      * @param value
      */
     public SignatureInfo(SignatureAlgorithm value){
+        signatureType=new SignatureType();
+        keyLocator=new KeyLocator();
         this.buildSignatureInfoBySignatureTypeValue(value);
     }
 
@@ -172,7 +179,12 @@ public class SignatureInfo implements TlvComponentBase, IEncodingAble {
         boolean findSignatureType=false;
         int elementSize=block.getSubElements().length();
         for (int i=0;i<elementSize;i++) {
-            Block cacheBlock=block.getSubElements().getBlock(i);
+            Block cacheBlock= null;
+            try {
+                cacheBlock = block.getSubElements().getBlock(i);
+            } catch (BlockException e) {
+                throw new ComponentException("SignatureInfo.wireDecode:"+e.getMessage());
+            }
             int type= 0;
             try {
                 type = cacheBlock.getType().getVlIntValue2Int();