test: add wasi readdir() test

This commit provides coverage for __wasi_fd_readdir().

PR-URL: #35202
Reviewed-By: Gus Caplan <me@gus.host>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Jiawen Geng <technicalcute@gmail.com>

test/wasi/c/readdir.c

@@ -0,0 +1,50 @@
+#include <assert.h>
+#include <dirent.h>
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+int main() {
+  DIR* dir;
+  struct dirent* entry;
+  char* platform;
+  int cnt;
+  int has_d_type;
+
+  platform = getenv("NODE_PLATFORM");
+  assert(platform != NULL);
+  has_d_type = (0 != strcmp(platform, "aix") && 0 != strcmp(platform, "sunos"));
+
+  dir = opendir("/sandbox");
+  assert(dir != NULL);
+
+  cnt = 0;
+  errno = 0;
+  while (NULL != (entry = readdir(dir))) {
+    if (strcmp(entry->d_name, "input.txt") == 0 ||
+        strcmp(entry->d_name, "input2.txt") == 0 ||
+        strcmp(entry->d_name, "notadir") == 0) {
+      if (has_d_type) {
+        assert(entry->d_type == DT_REG);
+      } else {
+        assert(entry->d_type == DT_UNKNOWN);
+      }
+    } else if (strcmp(entry->d_name, "subdir") == 0) {
+      if (has_d_type) {
+        assert(entry->d_type == DT_DIR);
+      } else {
+        assert(entry->d_type == DT_UNKNOWN);
+      }
+    } else {
+      assert("unexpected file");
+    }
+
+    cnt++;
+  }
+
+  assert(errno == 0);
+  assert(cnt == 4);
+  closedir(dir);
+  return 0;
+}

test/wasi/test-wasi.js

@@ -84,6 +84,11 @@ if (process.argv[2] === 'wasi-child') {
   runWASI({ test: 'notdir' });
   runWASI({ test: 'poll' });
   runWASI({ test: 'preopen_populates' });
+
+  if (!common.isWindows && process.platform !== 'android') {
+    runWASI({ test: 'readdir' });
+  }
+
   runWASI({ test: 'read_file', stdout: `hello from input.txt${EOL}` });
   runWASI({
     test: 'read_file_twice',