fix: harden simulator data contracts

tests/test-runner.js

@@ -8,7 +8,25 @@ globalThis.assertEqual = (actual, expected, message = "values differ") => {
   if (!Object.is(actual, expected)) throw new Error(`${message}: expected ${expected}, received ${actual}`);
 };
 
-await import("/tests/unit/contracts.test.js");
+try {
+  await import("/tests/unit/contracts.test.js");
+} catch (error) {
+  registeredTests.push({
+    name: "테스트 모듈을 불러온다",
+    callback: () => {
+      throw error;
+    },
+  });
+}
+
+if (registeredTests.length === 0) {
+  registeredTests.push({
+    name: "하나 이상의 테스트가 등록된다",
+    callback: () => {
+      throw new Error("등록된 테스트가 없습니다.");
+    },
+  });
+}
 
 const resultList = document.querySelector("#test-results");
 const summary = document.querySelector("#test-summary");