1 files changed, 43 insertions, 0 deletions
diff --git a/jstests/noPassthrough/oplog_writes_only_permitted_on_standalone.js b/jstests/noPassthrough/oplog_writes_only_permitted_on_standalone.js
new file mode 100644
index 00000000000..bb2af0f0ee7
--- /dev/null
+++ b/jstests/noPassthrough/oplog_writes_only_permitted_on_standalone.js
@@ -0,0 +1,43 @@
+/**
+ * Tests that oplog writes are forbidden on replica set members. In standalone mode, it is permitted
+ * to insert oplog entries.
+ * @tags: [
+ *   requires_persistence,
+ *   requires_replication,
+ * ]
+ */
+(function() {
+    "use strict";
+
+    const rst = new ReplSetTest({nodes: 1});
+    rst.startSet();
+    rst.initiate();
+
+    let conn = rst.getPrimary();
+    assert.writeOK(conn.getDB("test").coll.insert({_id: 0, a: 0}));
+
+    let oplog = conn.getDB("local").oplog.rs;
+
+    // Construct a valid oplog entry.
+    const lastOplogEntry = oplog.find().sort({ts: -1}).limit(1).toArray()[0];
+    const highestTS = lastOplogEntry.ts;
+    const toInsert = Object.extend(lastOplogEntry, {
+        op: "u",
+        ns: "test.coll",
+        o: {$set: {a: 1}},
+        o2: {_id: 0},
+        ts: Timestamp(highestTS.getTime(), highestTS.getInc() + 1)
+    });
+
+    jsTestLog("Test that oplog writes are banned when replication is enabled.");
+    assert.writeErrorWithCode(oplog.insert(toInsert), ErrorCodes.InvalidNamespace);
+
+    jsTestLog("Restart the node in standalone mode.");
+    rst.stop(0, undefined /*signal*/, undefined /*opts*/, {forRestart: true});
+    conn = rst.start(0, {noReplSet: true, noCleanData: true});
+
+    jsTestLog("Test that oplog writes are permitted in standalone mode.");
+    assert.writeOK(conn.getDB("local").oplog.rs.insert(toInsert));
+
+    rst.stopSet();
+}());