DRIVERS-3006 Consolidate CSOT change stream timeout tests

source/client-side-operations-timeout/tests/change-streams.yml

@@ -84,7 +84,7 @@ tests:
               command:
                 aggregate: *collectionName
                 maxTimeMS: { $$type: ["int", "long"] }
-  
+
   # If maxAwaitTimeMS is not set, timeoutMS should be refreshed for the getMore and the getMore should not have a
   # maxTimeMS field. This test requires a high timeout because the server applies a default 1000ms maxAwaitTime. To
   # ensure that the driver is refreshing the timeout between commands, the test blocks aggregate and getMore commands
@@ -170,10 +170,8 @@ tests:
                 collection: *collectionName
                 maxTimeMS: 1
 
-  # The timeout should be applied to the entire resume attempt, not individually to each command. The test creates a
-  # change stream with timeoutMS=200 which returns an empty initial batch and then sets a fail point to block both
-  # getMore and aggregate for 120ms each and fail with a resumable error. When the resume attempt happens, the getMore
-  # and aggregate block for longer than 200ms total, so it times out.
+  # If a resume is required for a next call on a change stream, the timeout MUST apply to the entirety of the initial
+  # getMore and all commands sent as part of the resume attempt.
   - description: "timeoutMS applies to full resume attempt in a next call"
     operations:
       - name: createChangeStream
@@ -225,7 +223,14 @@ tests:
                 aggregate: *collectionName
                 maxTimeMS: { $$type: ["int", "long"] }
 
-  - description: "change stream can be iterated again if previous iteration times out"
+  # [resumption] If a next call fails with a timeout error, drivers MUST NOT
+  # invalidate the change stream. The subsequent next call MUST perform a resume
+  # attempt to establish a new change stream on the server.
+  #
+  # [refresh] If a resume is required for a next call on a change stream, the
+  # timeout MUST apply to the entirety of the initial getMore and all commands
+  # sent as part of the resume attempt.
+  - description: "change stream iteration succeeds after a timeout error"
     operations:
       - name: createChangeStream
         object: *collection
@@ -248,14 +253,27 @@ tests:
               failCommands: ["getMore"]
               blockConnection: true
               blockTimeMS: 250
-      # The original aggregate didn't return any events so this should do a getMore and return a timeout error.
+      # Iterate until timeout.
       - name: iterateUntilDocumentOrError
         object: *changeStream
         expectError:
           isTimeoutError: true
-      # The previous iteration attempt timed out so this should re-create the change stream. We use iterateOnce rather
-      # than iterateUntilDocumentOrError because there haven't been any events and we only want to assert that the
-      # cursor was re-created.
+      # Block the resume aggregate for 150ms. If the timeout were exhausted from
+      # the previous call, this would fail immediately. With a fresh 200ms
+      # timeout, the 150ms delay should be acceptable.
+      - name: failPoint
+        object: testRunner
+        arguments:
+          client: *failPointClient
+          failPoint:
+            configureFailPoint: failCommand
+            mode: { times: 1 }
+            data:
+              failCommands: ["aggregate"]
+              blockConnection: true
+              blockTimeMS: 150
+      # A final iteration should succeed because the timeout is refreshed and
+      # the change stream was not invalidated.
       - name: iterateOnce
         object: *changeStream
     expectEvents:
@@ -267,27 +285,24 @@ tests:
               command:
                 aggregate: *collectionName
                 maxTimeMS: { $$type: ["int", "long"] }
-          # The iterateUntilDocumentOrError operation should send a getMore.
+          # The first iterateUntilDocumentOrError sends a getMore that times
+          # out.
           - commandStartedEvent:
               commandName: getMore
               databaseName: *databaseName
               command:
                 getMore: { $$type: ["int", "long"] }
                 collection: *collectionName
-          # The iterateOnce operation should re-create the cursor via an aggregate and then send a getMore to iterate
-          # the new cursor.
+          # The iterateOnce operation re-creates the cursor via an aggregate
+          # [resumption]. The aggregate is blocked for 150ms but succeeds
+          # because the timeout was refreshed to a fresh 200ms, proving the
+          # timeout is not shared with the previous timed-out call [refresh].
           - commandStartedEvent:
               commandName: aggregate
               databaseName: *databaseName
               command:
                 aggregate: *collectionName
                 maxTimeMS: { $$type: ["int", "long"] }
-          - commandStartedEvent:
-              commandName: getMore
-              databaseName: *databaseName
-              command:
-                getMore: { $$type: ["int", "long"] }
-                collection: *collectionName
 
   # The timeoutMS value should be refreshed for getMore's. This is a failure test. The createChangeStream operation
   # sets timeoutMS=200 and the getMore blocks for 250ms, causing iteration to fail with a timeout error.