Fix issue 208

documentdb_tests/compatibility/tests/core/operator/expressions/misc/sampleRate/test_smoke_sampleRate.py

@@ -1,7 +1,7 @@
 """
 Smoke test for $sampleRate expression.
 
-Tests basic $sampleRate expression functionality.
+Tests basic $sampleRate match expression functionality.
 """
 
 import pytest
@@ -12,11 +12,9 @@
 pytestmark = pytest.mark.smoke
 
 
-def test_smoke_sampleRate(collection):
-    """Test basic $sampleRate expression behavior."""
-    collection.insert_many(
-        [{"_id": 1, "value": 10}, {"_id": 2, "value": 20}, {"_id": 3, "value": 30}]
-    )
+def test_smoke_sampleRate_rate_one(collection):
+    """Test $sampleRate: 1.0 returns all documents (deterministic upper boundary)."""
+    collection.insert_many([{"_id": 1, "val": "a"}, {"_id": 2, "val": "b"}, {"_id": 3, "val": "c"}])
 
     result = execute_command(
         collection,
@@ -27,5 +25,22 @@ def test_smoke_sampleRate(collection):
         },
     )
 
-    expected = [{"_id": 1, "value": 10}, {"_id": 2, "value": 20}, {"_id": 3, "value": 30}]
-    assertSuccess(result, expected, msg="Should support $sampleRate expression")
+    expected = [{"_id": 1, "val": "a"}, {"_id": 2, "val": "b"}, {"_id": 3, "val": "c"}]
+    assertSuccess(result, expected, msg="$sampleRate: 1.0 should return all documents")
+
+
+def test_smoke_sampleRate_rate_zero(collection):
+    """Test $sampleRate: 0.0 returns no documents (deterministic lower boundary)."""
+    collection.insert_many([{"_id": 1, "val": "a"}, {"_id": 2, "val": "b"}, {"_id": 3, "val": "c"}])
+
+    result = execute_command(
+        collection,
+        {
+            "aggregate": collection.name,
+            "pipeline": [{"$match": {"$sampleRate": 0.0}}],
+            "cursor": {},
+        },
+    )
+
+    expected = []
+    assertSuccess(result, expected, msg="$sampleRate: 0.0 should return no documents")