lib/model: Remove some testing deadlocks (#6138)

lib/model/folder_sendrecv_test.go

@@ -253,8 +253,22 @@ func TestCopierFinder(t *testing.T) {
 
 	f.handleFile(requiredFile, copyChan, dbUpdateChan)
 
-	pulls := []pullBlockState{<-pullChan, <-pullChan, <-pullChan, <-pullChan}
-	finish := <-finisherChan
+	timeout := time.After(10 * time.Second)
+	pulls := make([]pullBlockState, 4)
+	for i := 0; i < 4; i++ {
+		select {
+		case pulls[i] = <-pullChan:
+		case <-timeout:
+			t.Fatalf("Timed out before receiving all 4 states on pullChan (already got %v)", i)
+		}
+	}
+	var finish *sharedPullerState
+	select {
+	case finish = <-finisherChan:
+	case <-timeout:
+		t.Fatal("Timed out before receiving 4 states on pullChan")
+	}
+
 	defer cleanupSharedPullerState(finish)
 
 	select {