1 files changed, 68 insertions, 0 deletions
diff --git a/jstests/core/explain4.js b/jstests/core/explain4.js
new file mode 100644
index 00000000000..d6d3d818a72
--- /dev/null
+++ b/jstests/core/explain4.js
@@ -0,0 +1,68 @@
+// Basic validation of explain output fields.
+
+t = db.jstests_explain4;
+t.drop();
+
+function checkField( explain, name, value ) {
+    assert( explain.hasOwnProperty( name ) );
+    if ( value != null ) {
+        assert.eq( value, explain[ name ], name );
+        // Check that the value is of the expected type.  SERVER-5288
+        assert.eq( typeof( value ), typeof( explain[ name ] ), 'type ' + name );
+    }
+}
+
+function checkNonCursorPlanFields( explain, matches, n ) {
+    checkField( explain, "n", n );
+    checkField( explain, "nscannedObjects", matches );
+    checkField( explain, "nscanned", matches );
+}
+
+function checkPlanFields( explain, matches, n ) {
+    checkField( explain, "cursor", "BasicCursor" );
+    // index related fields do not appear in non-indexed plan
+    assert(!("indexBounds" in explain));
+    checkNonCursorPlanFields( explain, matches, n );
+}
+
+function checkFields( matches, sort, limit ) {
+    cursor = t.find();
+    if ( sort ) {
+        print("sort is {a:1}");
+        cursor.sort({a:1});
+    }
+    if ( limit ) {
+        print("limit = " + limit);
+        cursor.limit( limit );
+    }
+    explain = cursor.explain( true );
+    printjson( explain );
+    checkPlanFields( explain, matches, matches > 0 ? 1 : 0 );
+    checkField( explain, "scanAndOrder", sort );
+    checkField( explain, "millis" );
+    checkField( explain, "nYields" );
+    checkField( explain, "nChunkSkips", 0 );
+    checkField( explain, "isMultiKey", false );
+    checkField( explain, "indexOnly", false );
+    checkField( explain, "server" );
+    checkField( explain, "allPlans" );
+    explain.allPlans.forEach( function( x ) { checkPlanFields( x, matches, matches ); } );
+}
+
+checkFields( 0, false );
+
+// If there's nothing in the collection, there's no point in verifying that a sort
+// is done.
+// checkFields( 0, true );
+
+t.save( {} );
+checkFields( 1, false );
+checkFields( 1, true );
+
+t.save( {} );
+checkFields( 1, false, 1 );
+
+// Check basic fields with multiple clauses.
+t.save( { _id:0 } );
+explain = t.find( { $or:[ { _id:0 }, { _id:1 } ] } ).explain( true );
+checkNonCursorPlanFields( explain, 1, 1 );