Minor refactorings

Author: patrickfav

src/main/java/at/favre/lib/bytes/MutableBytes.java

@@ -51,8 +51,7 @@ public boolean isMutable() {
      * @throws IndexOutOfBoundsException if newArray.length > internal length
      */
     public MutableBytes overwrite(byte[] newArray) {
-        overwrite(newArray, 0);
-        return this;
+        return overwrite(newArray, 0);
     }
 
     /**
@@ -87,8 +86,7 @@ public MutableBytes setByteAt(int index, byte newByte) {
      * @return this instance
      */
     public MutableBytes wipe() {
-        fill((byte) 0);
-        return this;
+        return fill((byte) 0);
     }
 
     /**
@@ -108,8 +106,7 @@ public MutableBytes fill(byte fillByte) {
      * @return this instance
      */
     public MutableBytes secureWipe() {
-        secureWipe(new SecureRandom());
-        return this;
+        return secureWipe(new SecureRandom());
     }
 
     /**

src/test/java/at/favre/lib/bytes/ABytesTest.java

@@ -27,7 +27,7 @@
 
 import static org.junit.Assert.*;
 
-abstract class ABytesTest {
+public abstract class ABytesTest {
     byte[] example_bytes_empty;
 
     byte[] example_bytes_one;

src/test/java/at/favre/lib/bytes/MutableBytesTest.java

@@ -106,7 +106,8 @@ public void setByteAtTest() {
 
         for (int i = 0; i < b.length(); i++) {
             byte old = b.byteAt(i);
-            b.setByteAt(i, (byte) 0);
+            MutableBytes bcopy = b.setByteAt(i, (byte) 0);
+            assertSame(b, bcopy);
             if (old != 0) {
                 assertNotEquals(old, b.byteAt(i));
             }