SERVER-46737 Support let variables for find command

1 files changed, 21 insertions, 1 deletions

diff --git a/jstests/noPassthroughWithMongod/command_let_variables.js b/jstests/noPassthroughWithMongod/command_let_variables.js
index 1b80977f0dd..c5d235dfe68 100644
--- a/jstests/noPassthroughWithMongod/command_let_variables.js
+++ b/jstests/noPassthroughWithMongod/command_let_variables.js
@@ -196,9 +196,29 @@ assert.commandWorked(db.runCommand({
 }));
 assert.eq(targetColl.aggregate({$match: {$expr: {$eq: ["$var", "INNER"]}}}).toArray().length, 1);
 
+// find
+let result = assert
+                 .commandWorked(db.runCommand({
+                     find: coll.getName(),
+                     let : {target_species: "Song Thrush (Turdus philomelos)"},
+                     filter: {$expr: {$eq: ["$Species", "$$target_species"]}},
+                     projection: {_id: 0}
+                 }))
+                 .cursor.firstBatch;
+expectedResults = {
+    Species: "Song Thrush (Turdus philomelos)",
+    population_trends: [
+        {term: {start: 1970, end: 2014}, pct_change: -53, annual: -1.7, trend: "weak decline"},
+        {term: {start: 2009, end: 2014}, pct_change: -4, annual: -0.88, trend: "no change"}
+    ]
+};
+
+assert.eq(result.length, 1);
+assert.eq(expectedResults, result[0]);
+
 // findAndModify
 assert.commandWorked(coll.insert({Species: "spy_bird"}));
-let result = db.runCommand({
+result = db.runCommand({
     findAndModify: coll.getName(),
     let : {target_species: "spy_bird"},
     query: {$expr: {$eq: ["$Species", "$$target_species"]}},