add drain hole 3mf export and import

tests/libslic3r/libslic3r_tests.cpp

@@ -11,4 +11,31 @@ TEST_CASE("sort_remove_duplicates", "[utils]") {
     REQUIRE(data_src == data_dst);
 }
 
+TEST_CASE("string_printf", "[utils]") {
+    SECTION("Empty format with empty data should return empty string") {
+        std::string outs = Slic3r::string_printf("");
+        REQUIRE(outs.empty());
+    }
+    
+    SECTION("String output length should be the same as input") {
+        std::string outs = Slic3r::string_printf("1234");
+        REQUIRE(outs.size() == 4);
+    }
+    
+    SECTION("String format should be interpreted as with sprintf") {
+        std::string outs = Slic3r::string_printf("%d %f %s", 10, 11.4, " This is a string");
+        char buffer[1024];
+        
+        sprintf(buffer, "%d %f %s", 10, 11.4, " This is a string");
+        
+        REQUIRE(outs.compare(buffer) == 0);
+    }
+    
+    SECTION("String format should survive large input data") {
+        std::string input(2048, 'A');
+        std::string outs = Slic3r::string_printf("%s", input.c_str());
+        REQUIRE(outs.compare(input) == 0);
+    }
+}
+
 }