JAVA-2305: Report correct maximum document size in BsonSerializationException

Author: jyemin

bson/src/main/org/bson/BsonBinaryWriter.java

@@ -373,8 +373,8 @@ private void writeCurrentName() {
     private void backpatchSize() {
         int size = bsonOutput.getPosition() - getContext().startPosition;
         if (size > maxDocumentSizeStack.peek()) {
-            throw new BsonSerializationException(format("Size %d is larger than MaxDocumentSize %d.", size,
-                                                        binaryWriterSettings.getMaxDocumentSize()));
+            throw new BsonSerializationException(format("Document size of %d is larger than maximum of %d.", size,
+                    maxDocumentSizeStack.peek()));
         }
         bsonOutput.writeInt32(bsonOutput.getPosition() - size, size);
     }

bson/src/test/unit/org/bson/BsonBinaryWriterTest.java

@@ -49,20 +49,29 @@ public void tearDown() {
         writer.close();
     }
 
-    @Test(expected = BsonSerializationException.class)
+    @Test
     public void shouldThrowWhenMaxDocumentSizeIsExceeded() {
-        writer.writeStartDocument();
-        writer.writeBinaryData("b", new BsonBinary(new byte[1024]));
-        writer.writeEndDocument();
+        try {
+            writer.writeStartDocument();
+            writer.writeBinaryData("b", new BsonBinary(new byte[1024]));
+            writer.writeEndDocument();
+            fail();
+        } catch (BsonSerializationException e) {
+            assertEquals("Document size of 1037 is larger than maximum of 1024.", e.getMessage());
+        }
     }
 
-    @Test(expected = BsonSerializationException.class)
+    @Test
     public void shouldThrowIfAPushedMaxDocumentSizeIsExceeded() {
-        writer.writeStartDocument();
-        writer.pushMaxDocumentSize(10);
-        writer.writeStartDocument("doc");
-        writer.writeString("s", "123456789");
-        writer.writeEndDocument();
+        try {
+            writer.writeStartDocument();
+            writer.pushMaxDocumentSize(10);
+            writer.writeStartDocument("doc");
+            writer.writeString("s", "123456789");
+            writer.writeEndDocument();
+        } catch (BsonSerializationException e) {
+            assertEquals("Document size of 22 is larger than maximum of 10.", e.getMessage());
+        }
     }
 
     @Test