diff --git a/src/gn/rust_project_writer.cc b/src/gn/rust_project_writer.cc
index 1dc9f7a..1845aee 100644
--- a/src/gn/rust_project_writer.cc
+++ b/src/gn/rust_project_writer.cc
@@ -169,6 +169,8 @@
   Crate sysroot_crate =
       Crate(SourceFile(crate_path), crate_index, std::string(crate), "2018");
 
+  sysroot_crate.AddConfigItem("debug_assertions");
+
   if (deps_lookup != sysroot_deps_map.end()) {
     auto deps = (*deps_lookup).second;
     for (auto dep : deps) {
@@ -255,6 +257,9 @@
 
   Crate crate = Crate(crate_root, crate_id, crate_label, edition);
 
+  crate.AddConfigItem("test");
+  crate.AddConfigItem("debug_assertions");
+
   for (auto& cfg : cfgs) {
     crate.AddConfigItem(cfg);
   }
diff --git a/src/gn/rust_project_writer_helpers_unittest.cc b/src/gn/rust_project_writer_helpers_unittest.cc
index 19501c4..23657ee 100644
--- a/src/gn/rust_project_writer_helpers_unittest.cc
+++ b/src/gn/rust_project_writer_helpers_unittest.cc
@@ -123,6 +123,7 @@
     "      ],\n"
     "      \"edition\": \"2018\",\n"
     "      \"cfg\": [\n"
+    "        \"debug_assertions\"\n"
     "      ]\n"
     "    },\n"
     "    {\n"
@@ -137,6 +138,7 @@
     "      ],\n"
     "      \"edition\": \"2018\",\n"
     "      \"cfg\": [\n"
+    "        \"debug_assertions\"\n"
     "      ]\n"
     "    },\n"
     "    {\n"
@@ -147,6 +149,7 @@
     "      ],\n"
     "      \"edition\": \"2018\",\n"
     "      \"cfg\": [\n"
+    "        \"debug_assertions\"\n"
     "      ]\n"
     "    },\n"
     "    {\n"
@@ -157,6 +160,7 @@
     "      ],\n"
     "      \"edition\": \"2018\",\n"
     "      \"cfg\": [\n"
+    "        \"debug_assertions\"\n"
     "      ]\n"
     "    },\n"
     "    {\n"
@@ -183,6 +187,7 @@
     "      ],\n"
     "      \"edition\": \"2018\",\n"
     "      \"cfg\": [\n"
+    "        \"debug_assertions\"\n"
     "      ]\n"
     "    },\n"
     "    {\n"
@@ -193,6 +198,7 @@
     "      ],\n"
     "      \"edition\": \"2018\",\n"
     "      \"cfg\": [\n"
+    "        \"debug_assertions\"\n"
     "      ]\n"
     "    },\n"
     "    {\n"
@@ -203,6 +209,7 @@
     "      ],\n"
     "      \"edition\": \"2018\",\n"
     "      \"cfg\": [\n"
+    "        \"debug_assertions\"\n"
     "      ]\n"
     "    },\n"
     "    {\n"
@@ -213,6 +220,7 @@
     "      ],\n"
     "      \"edition\": \"2018\",\n"
     "      \"cfg\": [\n"
+    "        \"debug_assertions\"\n"
     "      ]\n"
     "    },\n"
     "    {\n"
@@ -223,6 +231,7 @@
     "      ],\n"
     "      \"edition\": \"2018\",\n"
     "      \"cfg\": [\n"
+    "        \"debug_assertions\"\n"
     "      ]\n"
     "    },\n"
     "    {\n"
@@ -233,6 +242,7 @@
     "      ],\n"
     "      \"edition\": \"2018\",\n"
     "      \"cfg\": [\n"
+    "        \"debug_assertions\"\n"
     "      ]\n"
     "    },\n"
     "    {\n"
@@ -243,6 +253,7 @@
     "      ],\n"
     "      \"edition\": \"2018\",\n"
     "      \"cfg\": [\n"
+    "        \"debug_assertions\"\n"
     "      ]\n"
     "    },\n"
     "    {\n"
@@ -253,6 +264,7 @@
     "      ],\n"
     "      \"edition\": \"2018\",\n"
     "      \"cfg\": [\n"
+    "        \"debug_assertions\"\n"
     "      ]\n"
     "    },\n"
     "    {\n"
@@ -263,6 +275,7 @@
     "      ],\n"
     "      \"edition\": \"2018\",\n"
     "      \"cfg\": [\n"
+    "        \"debug_assertions\"\n"
     "      ]\n"
     "    },\n"
     "    {\n"
@@ -273,6 +286,7 @@
     "      ],\n"
     "      \"edition\": \"2018\",\n"
     "      \"cfg\": [\n"
+    "        \"debug_assertions\"\n"
     "      ]\n"
     "    },\n"
     "    {\n"
@@ -283,6 +297,7 @@
     "      ],\n"
     "      \"edition\": \"2018\",\n"
     "      \"cfg\": [\n"
+    "        \"debug_assertions\"\n"
     "      ]\n"
     "    },\n"
     "    {\n"
@@ -293,6 +308,7 @@
     "      ],\n"
     "      \"edition\": \"2018\",\n"
     "      \"cfg\": [\n"
+    "        \"debug_assertions\"\n"
     "      ]\n"
     "    },\n"
     "    {\n"
@@ -303,6 +319,7 @@
     "      ],\n"
     "      \"edition\": \"2018\",\n"
     "      \"cfg\": [\n"
+    "        \"debug_assertions\"\n"
     "      ]\n"
     "    },\n"
     "    {\n"
@@ -313,6 +330,7 @@
     "      ],\n"
     "      \"edition\": \"2018\",\n"
     "      \"cfg\": [\n"
+    "        \"debug_assertions\"\n"
     "      ]\n"
     "    },\n"
     "    {\n"
@@ -323,6 +341,7 @@
     "      ],\n"
     "      \"edition\": \"2018\",\n"
     "      \"cfg\": [\n"
+    "        \"debug_assertions\"\n"
     "      ]\n"
     "    },\n"
     "    {\n"
@@ -333,6 +352,7 @@
     "      ],\n"
     "      \"edition\": \"2018\",\n"
     "      \"cfg\": [\n"
+    "        \"debug_assertions\"\n"
     "      ]\n"
     "    },\n"
     "    {\n"
@@ -343,6 +363,7 @@
     "      ],\n"
     "      \"edition\": \"2018\",\n"
     "      \"cfg\": [\n"
+    "        \"debug_assertions\"\n"
     "      ]\n"
     "    },\n"
     "    {\n"
@@ -353,6 +374,7 @@
     "      ],\n"
     "      \"edition\": \"2018\",\n"
     "      \"cfg\": [\n"
+    "        \"debug_assertions\"\n"
     "      ]\n"
     "    }\n"
     "  ]\n"
diff --git a/src/gn/rust_project_writer_unittest.cc b/src/gn/rust_project_writer_unittest.cc
index a1910e7..7891576 100644
--- a/src/gn/rust_project_writer_unittest.cc
+++ b/src/gn/rust_project_writer_unittest.cc
@@ -54,6 +54,8 @@
       "      ],\n"
       "      \"edition\": \"2015\",\n"
       "      \"cfg\": [\n"
+      "        \"test\",\n"
+      "        \"debug_assertions\",\n"
       "        \"feature=\\\"foo_enabled\\\"\"\n"
       "      ]\n"
       "    }\n"
@@ -112,6 +114,8 @@
       "      ],\n"
       "      \"edition\": \"2015\",\n"
       "      \"cfg\": [\n"
+      "        \"test\",\n"
+      "        \"debug_assertions\"\n"
       "      ]\n"
       "    },\n"
       "    {\n"
@@ -126,6 +130,8 @@
       "      ],\n"
       "      \"edition\": \"2015\",\n"
       "      \"cfg\": [\n"
+      "        \"test\",\n"
+      "        \"debug_assertions\"\n"
       "      ]\n"
       "    }\n"
       "  ]\n"
@@ -195,6 +201,8 @@
       "      ],\n"
       "      \"edition\": \"2015\",\n"
       "      \"cfg\": [\n"
+      "        \"test\",\n"
+      "        \"debug_assertions\"\n"
       "      ]\n"
       "    },\n"
       "    {\n"
@@ -205,6 +213,8 @@
       "      ],\n"
       "      \"edition\": \"2015\",\n"
       "      \"cfg\": [\n"
+      "        \"test\",\n"
+      "        \"debug_assertions\"\n"
       "      ]\n"
       "    },\n"
       "    {\n"
@@ -223,6 +233,8 @@
       "      ],\n"
       "      \"edition\": \"2015\",\n"
       "      \"cfg\": [\n"
+      "        \"test\",\n"
+      "        \"debug_assertions\"\n"
       "      ]\n"
       "    }\n"
       "  ]\n"
@@ -306,6 +318,8 @@
       "      ],\n"
       "      \"edition\": \"2015\",\n"
       "      \"cfg\": [\n"
+      "        \"test\",\n"
+      "        \"debug_assertions\"\n"
       "      ]\n"
       "    },\n"
       "    {\n"
@@ -316,6 +330,8 @@
       "      ],\n"
       "      \"edition\": \"2015\",\n"
       "      \"cfg\": [\n"
+      "        \"test\",\n"
+      "        \"debug_assertions\"\n"
       "      ]\n"
       "    },\n"
       "    {\n"
@@ -334,6 +350,8 @@
       "      ],\n"
       "      \"edition\": \"2015\",\n"
       "      \"cfg\": [\n"
+      "        \"test\",\n"
+      "        \"debug_assertions\"\n"
       "      ]\n"
       "    }\n"
       "  ]\n"