snapshot of https://github.com/grpc/grpc-go.git (master, 2026-09-15; blobs > 131072B omitted)

balancer/endpointsharding/endpointsharding_test.go

@@ -0,0 +1,83 @@
+/*
+ *
+ * Copyright 2025 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package endpointsharding
+
+import (
+	"fmt"
+	"testing"
+
+	"google.golang.org/grpc/internal/grpctest"
+	"google.golang.org/grpc/resolver"
+)
+
+type s struct {
+	grpctest.Tester
+}
+
+func Test(t *testing.T) {
+	grpctest.RunSubTests(t, s{})
+}
+
+func (s) TestRotateEndpoints(t *testing.T) {
+	ep := func(addr string) resolver.Endpoint {
+		return resolver.Endpoint{Addresses: []resolver.Address{{Addr: addr}}}
+	}
+	endpoints := []resolver.Endpoint{ep("1"), ep("2"), ep("3"), ep("4"), ep("5")}
+	testCases := []struct {
+		rval int
+		want []resolver.Endpoint
+	}{
+		{
+			rval: 0,
+			want: []resolver.Endpoint{ep("1"), ep("2"), ep("3"), ep("4"), ep("5")},
+		},
+		{
+			rval: 1,
+			want: []resolver.Endpoint{ep("2"), ep("3"), ep("4"), ep("5"), ep("1")},
+		},
+		{
+			rval: 2,
+			want: []resolver.Endpoint{ep("3"), ep("4"), ep("5"), ep("1"), ep("2")},
+		},
+		{
+			rval: 3,
+			want: []resolver.Endpoint{ep("4"), ep("5"), ep("1"), ep("2"), ep("3")},
+		},
+		{
+			rval: 4,
+			want: []resolver.Endpoint{ep("5"), ep("1"), ep("2"), ep("3"), ep("4")},
+		},
+	}
+
+	defer func(r func(int) int) {
+		randIntN = r
+	}(randIntN)
+
+	for _, tc := range testCases {
+		t.Run(fmt.Sprint(tc.rval), func(t *testing.T) {
+			randIntN = func(int) int {
+				return tc.rval
+			}
+			got := rotateEndpoints(endpoints)
+			if fmt.Sprint(got) != fmt.Sprint(tc.want) {
+				t.Fatalf("rand=%v; rotateEndpoints(%v) = %v; want %v", tc.rval, endpoints, got, tc.want)
+			}
+		})
+	}
+}