Build a subobject without recopying the contents

dbtests/jsobjtests.cpp

@@ -25,6 +25,16 @@
 #include "dbtests.h"
 
 namespace JsobjTests {
+    class BufBuilderBasic {
+    public:
+        void run() {
+            BufBuilder b( 0 );
+            b.append( "foo" );
+            ASSERT_EQUALS( 4, b.len() );
+            ASSERT( strcmp( "foo", b.buf() ) == 0 );
+        }
+    };
+    
     class BSONElementBasic {
     public:
         void run() {
@@ -571,9 +581,26 @@ namespace JsobjTests {
         
     } // namespace ValueStreamTests
     
+    class SubObjectBuilder {
+    public:
+        void run() {
+            BSONObjBuilder b1;
+            b1.append( "a", "bcd" );
+            BSONObjBuilder b2( b1.subobjStart( "foo" ) );
+            b2.append( "ggg", 44.0 );
+            b2.done();
+            b1.append( "f", 10.0 );
+            BSONObj ret = b1.done();
+            out() << "ret: " << ret << endl;
+            ASSERT( ret.valid() );
+            ASSERT( ret.woCompare( fromjson( "{a:'bcd',foo:{ggg:44},f:10}" ) ) == 0 );
+        }
+    };
+    
     class All : public UnitTest::Suite {
     public:
         All() {
+            add< BufBuilderBasic >();
             add< BSONElementBasic >();
             add< BSONObjTests::Create >();
             add< BSONObjTests::WoCompareBasic >();
@@ -626,6 +653,7 @@ namespace JsobjTests {
             add< ValueStreamTests::LabelDoubleShares >();
             add< ValueStreamTests::LabelMulti >();
             add< ValueStreamTests::Unallowed >();
+            add< SubObjectBuilder >();
         }
     };