SERVER-33667 Test that readConcern level snapshot is not allowed for agg explain

1 files changed, 29 insertions, 15 deletions

diff --git a/jstests/noPassthrough/agg_explain_read_concern.js b/jstests/noPassthrough/agg_explain_read_concern.js
index 408c1e4cc80..c5b7e2b8621 100644
--- a/jstests/noPassthrough/agg_explain_read_concern.js
+++ b/jstests/noPassthrough/agg_explain_read_concern.js
@@ -24,43 +24,57 @@
     rst.startSet();
     rst.initiate();
 
-    let primary = rst.getPrimary();
-    let testDB = primary.getDB("test");
-    let coll = testDB.agg_explain_read_concern;
+    const primary = rst.getPrimary();
+    const session = primary.getDB("test").getMongo().startSession({causalConsistency: false});
+    const sessionDB = session.getDatabase("test");
+    const coll = sessionDB.agg_explain_read_concern;
 
     // Test that explain is legal with readConcern "local".
     assert.commandWorked(coll.explain().aggregate([], {readConcern: {level: "local"}}));
-    assert.commandWorked(testDB.runCommand(
+    assert.commandWorked(sessionDB.runCommand(
         {aggregate: coll.getName(), pipeline: [], explain: true, readConcern: {level: "local"}}));
-    assert.commandWorked(testDB.runCommand({
+    assert.commandWorked(sessionDB.runCommand({
         explain: {aggregate: coll.getName(), pipeline: [], cursor: {}},
         readConcern: {level: "local"}
     }));
 
     // Test that explain is illegal with other readConcern levels.
-    // TODO SERVER-33354: Add "snapshot" once the aggregate command supports.
-    let nonLocalReadConcerns = ["majority", "available", "linearizable"];
+    const nonLocalReadConcerns = ["majority", "available", "linearizable", "snapshot"];
     nonLocalReadConcerns.forEach(function(readConcernLevel) {
-        assert.throws(() => coll.explain().aggregate([], {readConcern: {level: readConcernLevel}}));
-
-        let cmdRes = testDB.runCommand({
+        let aggCmd = {
             aggregate: coll.getName(),
             pipeline: [],
             explain: true,
             readConcern: {level: readConcernLevel}
-        });
+        };
+        let explainCmd = {
+            explain: {aggregate: coll.getName(), pipeline: [], cursor: {}},
+            readConcern: {level: readConcernLevel}
+        };
+
+        if (readConcernLevel === "snapshot") {
+            if (!sessionDB.serverStatus().storageEngine.supportsSnapshotReadConcern) {
+                return;
+            }
+            aggCmd.txnNumber = NumberLong(0);
+            explainCmd.txnNumber = NumberLong(1);
+
+        } else {
+            assert.throws(
+                () => coll.explain().aggregate([], {readConcern: {level: readConcernLevel}}));
+        }
+
+        let cmdRes = sessionDB.runCommand(aggCmd);
         assert.commandFailedWithCode(cmdRes, ErrorCodes.InvalidOptions, tojson(cmdRes));
         let expectedErrStr = "aggregate command does not support non-local readConcern";
         assert.neq(cmdRes.errmsg.indexOf(expectedErrStr), -1, tojson(cmdRes));
 
-        cmdRes = testDB.runCommand({
-            explain: {aggregate: coll.getName(), pipeline: [], cursor: {}},
-            readConcern: {level: readConcernLevel}
-        });
+        cmdRes = sessionDB.runCommand(explainCmd);
         assert.commandFailedWithCode(cmdRes, ErrorCodes.InvalidOptions, tojson(cmdRes));
         expectedErrStr = "Command does not support read concern";
         assert.neq(cmdRes.errmsg.indexOf(expectedErrStr), -1, tojson(cmdRes));
     });
 
+    session.endSession();
     rst.stopSet();
 }());