PCSM-261. Add test case for avgObjSize decoding error (#171)

Co-authored-by: Adnan <chupe@chupe.ba>

Author: sandraromanchenko

tests/test_collections_sharded.py

@@ -98,6 +98,21 @@ def test_clone_document_sharded(t: Testing, phase: Runner.Phase):
 
     t.compare_all_sharded()
 
+@pytest.mark.parametrize("phase", [Runner.Phase.CLONE])
+def test_clone_document_sharded_with_varying_sizes(t: Testing, phase: Runner.Phase):
+    with t.run(phase):
+        t.source["db_1"].create_collection("coll_1")
+        t.source.admin.command("shardCollection", "db_1.coll_1", key={"_id": "hashed"})
+        # insert documents with varying sizes to produce fractional avgObjSize
+        docs = [
+            {"_id": 1, "name": "Alice", "age": 30, "data": "x" * 15},
+            {"_id": 2, "name": "Bob", "age": 25, "data": "y" * 47},
+            {"_id": 3, "name": "Charlie", "age": 35, "data": "z" * 73},
+            {"_id": 4, "name": "Diana", "age": 28, "data": "a" * 22},
+            {"_id": 5, "name": "Eve", "age": 32, "data": "b" * 91},
+        ]
+        t.source["db_1"]["coll_1"].insert_many(docs)
+    t.compare_all_sharded()
 
 @pytest.mark.parametrize("phase", [Runner.Phase.APPLY])
 def test_shard_key_update_duplicate_key_error(t: Testing, phase: Runner.Phase):

topo/topo.go

@@ -127,11 +127,11 @@ type DBStats struct {
 // CollStats represents the result of the [GetCollStats].
 type CollStats struct {
 	// Count is the number of documents in the collection.
-	Count int64 `bson:"count"`
+	Count int64 `bson:"count,truncate"`
 	// Size is the total size of the collection.
-	Size int64 `bson:"size"`
+	Size int64 `bson:"size,truncate"`
 	// AvgObjSize is the average size of documents in the collection.
-	AvgObjSize int64 `bson:"avgObjSize"`
+	AvgObjSize int64 `bson:"avgObjSize,truncate"`
 }
 
 // SayHello runs the db.hello() command and returns the [Hello].

topo/topo_test.go

@@ -6,9 +6,33 @@ import (
 	"testing"
 	"time"
 
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"go.mongodb.org/mongo-driver/v2/bson"
 	"go.mongodb.org/mongo-driver/v2/mongo"
 )
 
+func TestCollStats_DecodeFromFloat64(t *testing.T) {
+	t.Parallel()
+
+	input := bson.M{
+		"count":      0.0,
+		"size":       73179136.0,
+		"avgObjSize": 0.0,
+	}
+
+	data, err := bson.Marshal(input)
+	require.NoError(t, err)
+
+	var stats CollStats
+	err = bson.Unmarshal(data, &stats)
+	require.NoError(t, err)
+
+	assert.Equal(t, int64(0), stats.Count)
+	assert.Equal(t, int64(73179136), stats.Size)
+	assert.Equal(t, int64(0), stats.AvgObjSize)
+}
+
 func TestRunWithRetry_NonTransientError(t *testing.T) {
 	t.Parallel()