test: add wasi test for freopen()

This test provides missing coverage for __wasi_fd_renumber().

PR-URL: #31432
Reviewed-By: Tobias Nießen <tniessen@tnie.de>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: David Carlier <devnexen@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Jiawen Geng <technicalcute@gmail.com>

test/fixtures/wasi/input2.txt

@@ -0,0 +1 @@
+hello from input2.txt

test/wasi/c/freopen.c

@@ -0,0 +1,16 @@
+#include <assert.h>
+#include <stdio.h>
+
+int main() {
+  FILE* file_orig = fopen("/sandbox/input.txt", "r");
+  assert(file_orig != NULL);
+  FILE* file_new = freopen("/sandbox/input2.txt", "r", file_orig);
+  assert(file_new != NULL);
+
+  int c = fgetc(file_new);
+  while (c != EOF) {
+    int wrote = fputc((char)c, stdout);
+    assert(wrote != EOF);
+    c = fgetc(file_new);
+  }
+}

test/wasi/test-wasi.js

@@ -60,6 +60,7 @@ if (process.argv[2] === 'wasi-child') {
   runWASI({ test: 'clock_getres' });
   runWASI({ test: 'exitcode', exitCode: 120 });
   runWASI({ test: 'fd_prestat_get_refresh' });
+  runWASI({ test: 'freopen', stdout: `hello from input2.txt${EOL}` });
   runWASI({ test: 'getentropy' });
   runWASI({ test: 'getrusage' });
   runWASI({ test: 'gettimeofday' });