diff --git a/tests/fff_print/test_flow.cpp b/tests/fff_print/test_flow.cpp
index 584fb8dd7..dc14d96ee 100644
--- a/tests/fff_print/test_flow.cpp
+++ b/tests/fff_print/test_flow.cpp
@@ -29,7 +29,7 @@ SCENARIO("Extrusion width specifics", "[!mayfail]") {
 
         WHEN("first layer width set to 2mm") {
             Slic3r::Model model;
-            config.set_deserialize("first_layer_extrusion_width", "2");
+            config.set("first_layer_extrusion_width", 2);
             Slic3r::Print print;
             Slic3r::Test::init_print({TestMesh::cube_20x20x20}, print, model, config);
 
diff --git a/tests/fff_print/test_print.cpp b/tests/fff_print/test_print.cpp
index d0faff544..484e6018e 100644
--- a/tests/fff_print/test_print.cpp
+++ b/tests/fff_print/test_print.cpp
@@ -74,7 +74,7 @@ SCENARIO("Print: Changing number of solid surfaces does not cause all surfaces t
         test_is_solid_infill(0, 39); // should be solid
         test_is_solid_infill(0, 38); // should be solid
         WHEN("Model is re-sliced with top_solid_layers == 3") {
-			config.opt_int("top_solid_layers") = 3;
+			config.set("top_solid_layers", 3);
 			print.apply(model, config);
             print.process();
             THEN("Print object does not have 0 solid bottom layers.") {
diff --git a/tests/fff_print/test_skirt_brim.cpp b/tests/fff_print/test_skirt_brim.cpp
index e57940575..9fabb7aa6 100644
--- a/tests/fff_print/test_skirt_brim.cpp
+++ b/tests/fff_print/test_skirt_brim.cpp
@@ -244,7 +244,7 @@ SCENARIO("Original Slic3r Skirt/Brim tests", "[!mayfail]") {
             }
         }
         WHEN("Large minimum skirt length is used.") {
-            config.opt_float("min_skirt_length") = 20;
+            config.set("min_skirt_length", 20);
             THEN("Gcode generation doesn't crash") {
                 REQUIRE(! Slic3r::Test::slice({TestMesh::cube_20x20x20}, config).empty());
             }
diff --git a/xs/src/perlglue.cpp b/xs/src/perlglue.cpp
index 463f7d21b..c3cd7e616 100644
--- a/xs/src/perlglue.cpp
+++ b/xs/src/perlglue.cpp
@@ -299,7 +299,7 @@ bool ConfigBase__set_deserialize(ConfigBase* THIS, const t_config_option_key &op
     size_t len;
     const char * c = SvPV(str, len);
     std::string value(c, len);
-    return THIS->set_deserialize(opt_key, value);
+    return THIS->set_deserialize_nothrow(opt_key, value);
 }
 
 void ConfigBase__set_ifndef(ConfigBase* THIS, const t_config_option_key &opt_key, SV* value, bool deserialize)