Update largeWriteTest

Improves the readability of the test. The assertions are clearer and include descriptive messages, making it easier to identify which assertion fails. This enhances code maintainability, understanding and debugging efficiency.

Author: pedrinhoeu

janusgraph-test/src/test/java/org/janusgraph/graphdb/serializer/SerializerTest.java

@@ -245,8 +245,8 @@ public void largeWriteTest() {
         out.writeObjectNotNull(str.toString());
         ReadBuffer b = out.getStaticBuffer().asReadBuffer();
         if (printStats) log.debug(bufferStats(b));
-        assertEquals(str.toString(), serialize.readObjectNotNull(b, String.class));
-        assertFalse(b.hasRemaining());
+        assertEquals(str.toString(), serialize.readObjectNotNull(b, String.class), "Serialized string does not match the original string");
+        assertFalse(b.hasRemaining(), "The buffer has remaining data after reading");
     }
 
     @Test