1 files changed, 34 insertions, 1 deletions
diff --git a/jstests/aggregation/sources/graphLookup/collation_graphlookup.js b/jstests/aggregation/sources/graphLookup/collation_graphlookup.js
index f3fbcf2ee34..00aa20fc404 100644
--- a/jstests/aggregation/sources/graphLookup/collation_graphlookup.js
+++ b/jstests/aggregation/sources/graphLookup/collation_graphlookup.js
@@ -46,7 +46,8 @@ assert.eq(1, res.length);
 assert.eq("erica", res[0].username);
 assert.eq(2, res[0].friendUsers.length);
 
-// Negative test: ensure that we don't find any friends when the collation is simple.
+// Negative test: The local collation does not have a default collation, and so we use the simple
+// collation. Ensure that we don't find any friends when the collation is simple.
 res = coll.aggregate([
                   {$match: {username: "erica"}},
                   {
@@ -64,6 +65,38 @@ assert.eq(1, res.length);
 assert.eq("erica", res[0].username);
 assert.eq(0, res[0].friendUsers.length);
 
+// Create a foreign collection with a case-insensitive default collation.
+foreignColl.drop();
+assert.commandWorked(db.createCollection(foreignColl.getName(), caseInsensitiveUS));
+assert.commandWorked(foreignColl.insert([{username: "JEREMY"}, {username: "JIMMY"}]));
+
+// Insert some more documents into the local collection.
+assert.commandWorked(coll.insert({username: "fiona", friends: ["jeremy"]}));
+assert.commandWorked(coll.insert({username: "gretchen", friends: ["jimmy"]}));
+
+// Test that $graphLookup uses the simple collation in the case where the collection on which it is
+// run does not have a default collation, and that this collation is used instead of the default
+// collation of the foreign collection. Exercises the fix for SERVER-43350.
+res = coll.aggregate([{$match: {username: {$in: ["erica", "fiona", "gretchen"]}}},
+                  {
+                    $graphLookup: {
+                        from: foreignColl.getName(),
+                        startWith: "$friends",
+                        connectFromField: "friends",
+                        connectToField: "username",
+                        as: "friendUsers"
+                    }
+                  }
+              ])
+              .toArray();
+assert.eq(3, res.length, tojson(res));
+for (let i = 0; i < res.length; ++i) {
+    assert(["erica", "fiona", "gretchen"].includes(res[i].username));
+    assert.eq(0, res[i].friendUsers.length);
+}
+
+// Recreate the local collection with a case-insensitive default collation, and the foreign
+// collection with a case-sensitive default collation.
 coll.drop();
 assert.commandWorked(db.createCollection(coll.getName(), caseInsensitiveUS));
 assert.writeOK(coll.insert({username: "erica", friends: ["jeremy", "jimmy"]}));