diff --git a/js/src/jsapi-tests/moz.build b/js/src/jsapi-tests/moz.build
index e1b8625f2f48..5d11d17a2877 100644
--- a/js/src/jsapi-tests/moz.build
+++ b/js/src/jsapi-tests/moz.build
@@ -144,7 +144,7 @@ if CONFIG['NIGHTLY_BUILD']:
         'testErrorInterceptor.cpp',
     ]
 
-if CONFIG['JS_BUILD_BINAST'] and CONFIG['JS_STANDALONE'] and CONFIG['OS_TARGET'] != 'WINNT':
+if CONFIG['JS_BUILD_BINAST'] and CONFIG['JS_STANDALONE']:
     # Standalone builds leave the source directory untouched,
     # which lets us run tests with the data files intact.
     # Otherwise, in the current state of the build system,
diff --git a/js/src/jsapi-tests/testBinASTReader.cpp b/js/src/jsapi-tests/testBinASTReader.cpp
index 35c0dd99d8e1..f6ceebf431f2 100644
--- a/js/src/jsapi-tests/testBinASTReader.cpp
+++ b/js/src/jsapi-tests/testBinASTReader.cpp
@@ -81,11 +81,17 @@ runTestFromPath(JSContext* cx, const char* path)
 #elif defined(XP_WIN)
     MOZ_ASSERT(path[pathlen - 1] == '\\');
 
-    const char PATTERN[] = "*";
+    Vector<char> pattern(cx);
+    if (!pattern.append(path, pathlen))
+        MOZ_CRASH();
+    if (!pattern.append('*'))
+        MOZ_CRASH();
+    if (!pattern.append('\0'))
+        MOZ_CRASH();
 
     WIN32_FIND_DATA FindFileData;
     enterJsDirectory();
-    HANDLE hFind = FindFirstFile(PATTERN, &FindFileData);
+    HANDLE hFind = FindFirstFile(pattern.begin(), &FindFileData);
     exitJsDirectory();
     for (bool found = (hFind != INVALID_HANDLE_VALUE);
             found;