clientv3/integration: test large KV requests

Signed-off-by: Gyuho Lee <gyuhox@gmail.com>

clientv3/integration/kv_test.go

@@ -861,3 +861,46 @@ func TestKVPutAtMostOnce(t *testing.T) {
 		t.Fatalf("expected version <= 10, got %+v", resp.Kvs[0])
 	}
 }
+
+// TestKVLargeRequests ensures that configurable MaxRequestBytes
+// works as intended for clients.
+func TestKVLargeRequests(t *testing.T) {
+	defer testutil.AfterTest(t)
+	tests := []struct {
+		maxRequestBytes uint
+		valueSize       int
+		expectError     error
+	}{
+		{1, 1024, rpctypes.ErrRequestTooLarge},
+
+		// without proper client-side receive size limit
+		// "code = ResourceExhausted desc = grpc: received message larger than max (5242929 vs. 4194304)"
+		{7 * 1024 * 1024, 5 * 1024 * 1024, nil},
+
+		{10 * 1024 * 1024, 10 * 1024 * 1024, rpctypes.ErrRequestTooLarge},
+		{10 * 1024 * 1024, 10*1024*1024 + 5, rpctypes.ErrRequestTooLarge},
+	}
+	for i, test := range tests {
+		clus := integration.NewClusterV3(t,
+			&integration.ClusterConfig{
+				Size:            1,
+				MaxRequestBytes: test.maxRequestBytes,
+			},
+		)
+		cli := clus.Client(0)
+		_, err := cli.Put(context.TODO(), "foo", strings.Repeat("a", test.valueSize))
+		if err != test.expectError {
+			t.Errorf("#%d: expected %v, got %v", i, test.expectError, err)
+		}
+
+		// put request went through, now expects large response back
+		if err == nil {
+			_, err = cli.Get(context.TODO(), "foo")
+			if err != nil {
+				t.Errorf("#%d: get expected no error, got %v", i, err)
+			}
+		}
+
+		clus.Terminate(t)
+	}
+}