SERVER-41183 Add test suites for change streams with transactions

5 files changed, 29 insertions, 6 deletions

diff --git a/jstests/change_streams/include_cluster_time.js b/jstests/change_streams/include_cluster_time.js
index 405bf2d5b16..d035a92f517 100644
--- a/jstests/change_streams/include_cluster_time.js
+++ b/jstests/change_streams/include_cluster_time.js
@@ -1,4 +1,9 @@
 // Tests that each change in the stream will include the cluster time at which it happened.
+//
+// This test expects each change stream result to have an operationTime based on the clusterTime in
+// the oplog entry. When operations get bundled into a transaction, their operationTime is instead
+// based on the commit oplog entry, which would cause this test to fail.
+// @tags: [change_stream_does_not_expect_txns]
 (function() {
     "use strict";
 
diff --git a/jstests/change_streams/report_latest_observed_oplog_timestamp.js b/jstests/change_streams/report_latest_observed_oplog_timestamp.js
index 45abd52ada9..56754613b47 100644
--- a/jstests/change_streams/report_latest_observed_oplog_timestamp.js
+++ b/jstests/change_streams/report_latest_observed_oplog_timestamp.js
@@ -1,6 +1,10 @@
 // Tests that an aggregate with a $changeStream stage will report the latest optime read in
 // the oplog by its cursor. This is information is needed in order to correctly merge the results
 // from the various shards on mongos.
+//
+// This test expects operations timestamps from a change stream to strictly increase with each
+// operation, which does not happen when the operations get grouped into a transaction.
+// @tags: [change_stream_does_not_expect_txns]
 (function() {
     "use strict";
 
diff --git a/jstests/change_streams/required_as_first_stage.js b/jstests/change_streams/required_as_first_stage.js
index 9eb15db9e9d..bdc0b43ba0c 100644
--- a/jstests/change_streams/required_as_first_stage.js
+++ b/jstests/change_streams/required_as_first_stage.js
@@ -1,4 +1,9 @@
 // Tests that the $changeStream stage can only be present as the first stage in the pipeline.
+//
+// The passthrough logic that bundles operations into transactions needs to be able identify change
+// stream aggregations so as to avoid running them in a transaction, but that code would fail to
+// recognize the intentionally malformed aggergations that we test here.
+// @tags: [change_stream_does_not_expect_txns]
 (function() {
     "use strict";
 
diff --git a/jstests/change_streams/resume_from_high_water_mark_token.js b/jstests/change_streams/resume_from_high_water_mark_token.js
index bc63fdb33d9..973fc32d9c9 100644
--- a/jstests/change_streams/resume_from_high_water_mark_token.js
+++ b/jstests/change_streams/resume_from_high_water_mark_token.js
@@ -160,18 +160,22 @@
     const otherCollection = assertCreateCollection(db, otherCollName);
     const adminDB = db.getSiblingDB("admin");
 
-    // Open a stream on the test collection. Write one document to the test collection and one to
-    // the unrelated collection, in order to push the postBatchResumeToken (PBRT) past the last
-    // related event.
+    // Open a stream on the test collection, and write a document to it.
     csCursor = testCollection.watch();
     assert.commandWorked(testCollection.insert({_id: docId++}));
-    assert.commandWorked(otherCollection.insert({}));
 
-    // Consume all events. The PBRT of the batch should be greater than the last event, which
-    // guarantees that it is a synthetic high-water-mark token.
+    // Write an event to the unrelated collection in order to advance the PBRT, and then consume all
+    // events. When we see a PBRT that is greater than the timestamp of the last event (stored in
+    // 'relatedEvent'), we know it must be a synthetic high-water-mark token.
+    //
+    // Note that the first insert into the unrelated collection may not be enough to advance the
+    // PBRT; some passthroughs will group the unrelated write into a transaction with the related
+    // write, giving them the same timestamp. We put the unrelated insert into the assert.soon loop,
+    // so that it will eventually get its own transaction with a new timestamp.
     let relatedEvent = null;
     let hwmToken = null;
     assert.soon(() => {
+        assert.commandWorked(otherCollection.insert({}));
         if (csCursor.hasNext()) {
             relatedEvent = csCursor.next();
         }
diff --git a/jstests/change_streams/shell_helper.js b/jstests/change_streams/shell_helper.js
index f63eba06df7..a044ba76e50 100644
--- a/jstests/change_streams/shell_helper.js
+++ b/jstests/change_streams/shell_helper.js
@@ -1,6 +1,11 @@
 // Test change streams related shell helpers and options passed to them. Note that, while we only
 // call the DBCollection.watch helper in this file, it will be redirected to the DB.watch or
 // Mongo.watch equivalents in the whole_db and whole_cluster passthroughs.
+//
+// This test expects each change stream result to have an operationTime based on the clusterTime in
+// the oplog entry. When operations get bundled into a transaction, their operationTime is instead
+// based on the commit oplog entry, which would cause this test to fail.
+// @tags: [change_stream_does_not_expect_txns]
 (function() {
     "use strict";