1 files changed, 61 insertions, 0 deletions
diff --git a/jstests/core/count6.js b/jstests/core/count6.js
new file mode 100644
index 00000000000..44c5fa33bc7
--- /dev/null
+++ b/jstests/core/count6.js
@@ -0,0 +1,61 @@
+// Some correctness checks for fast and normal count modes, including with skip and limit.
+
+t = db.jstests_count6;
+
+function checkCountForObject( obj ) {
+    t.drop();
+    t.ensureIndex( {b:1,a:1} );
+    
+    function checkCounts( query, expected ) {
+        assert.eq( expected, t.count( query ) , "A1" );
+        assert.eq( expected, t.find( query ).skip( 0 ).limit( 0 ).count( true ) , "A2" );
+        // Check proper counts with various skip and limit specs.
+        for( var skip = 1; skip <= 2; ++skip ) {
+            for( var limit = 1; limit <= 2; ++limit ) {
+                assert.eq( Math.max( expected - skip, 0 ), t.find( query ).skip( skip ).count( true ) , "B1" );
+                assert.eq( Math.min( expected, limit ), t.find( query ).limit( limit ).count( true ) , "B2" );
+                assert.eq( Math.min( Math.max( expected - skip, 0 ), limit ), t.find( query ).skip( skip ).limit( limit ).count( true ) , "B4" );
+
+                // Check limit(x) = limit(-x)
+                assert.eq( t.find( query ).limit( limit ).count( true ),
+                           t.find( query ).limit( -limit ).count( true ) , "C1" );
+                assert.eq( t.find( query ).skip( skip ).limit( limit ).count( true ),
+                           t.find( query ).skip( skip ).limit( -limit ).count( true ) , "C2" );
+            }
+        }
+
+        // Check limit(0) has no effect
+        assert.eq( expected, t.find( query ).limit( 0 ).count( true ) , "D1" );
+        assert.eq( Math.max( expected - skip, 0 ),
+                   t.find( query ).skip( skip ).limit( 0 ).count( true ) , "D2" );
+        assert.eq( expected, t.getDB().runCommand({ count: t.getName(),
+                        query: query, limit: 0 }).n , "D3" );
+        assert.eq( Math.max( expected - skip, 0 ),
+                   t.getDB().runCommand({ count: t.getName(),
+                               query: query, limit: 0, skip: skip }).n , "D4" );
+    }
+
+    for( var i = 0; i < 5; ++i ) {
+        checkCounts( {a:obj.a,b:obj.b}, i );
+        checkCounts( {b:obj.b,a:obj.a}, i );
+        t.insert( obj );    
+    }
+
+    t.insert( {a:true,b:true} );
+    t.insert( {a:true,b:1} );
+    t.insert( {a:false,b:1} );
+    t.insert( {a:false,b:true} );
+    t.insert( {a:false,b:false} );
+
+    checkCounts( {a:obj.a,b:obj.b}, i );
+    checkCounts( {b:obj.b,a:obj.a}, i );
+
+    // Check with no query
+    checkCounts( {}, 10 );
+}
+
+// Check fast count mode.
+checkCountForObject( {a:true,b:false} );
+
+// Check normal count mode.
+checkCountForObject( {a:1,b:0} );