diff --git a/dlls/ucrtbase/tests/Makefile.in b/dlls/ucrtbase/tests/Makefile.in
index cd01a3aacb97..ea9e589113c7 100644
--- a/dlls/ucrtbase/tests/Makefile.in
+++ b/dlls/ucrtbase/tests/Makefile.in
@@ -5,6 +5,7 @@ EXTRADEFS = -fno-builtin
 SOURCES = \
 	cpp.c \
 	environ.c \
+	file.c \
 	misc.c \
 	printf.c \
 	scanf.c \
diff --git a/dlls/ucrtbase/tests/file.c b/dlls/ucrtbase/tests/file.c
new file mode 100644
index 000000000000..4671e641dbe0
--- /dev/null
+++ b/dlls/ucrtbase/tests/file.c
@@ -0,0 +1,88 @@
+/*
+ * Unit test suite for file functions
+ *
+ * Copyright 2024 Eric Pouech for CodeWeavers
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
+ */
+
+#include "wine/test.h"
+
+static void test_std_stream_buffering(void)
+{
+    int dup_fd, ret, pos;
+    FILE *file;
+    char ch;
+
+    dup_fd = _dup(STDOUT_FILENO);
+    ok(dup_fd != -1, "_dup failed\n");
+
+    file = freopen("std_stream_test.tmp", "w", stdout);
+    ok(file != NULL, "freopen failed\n");
+
+    ret = fprintf(stdout, "test");
+    pos = _telli64(STDOUT_FILENO);
+
+    fflush(stdout);
+    _dup2(dup_fd, STDOUT_FILENO);
+    close(dup_fd);
+    setvbuf(stdout, NULL, _IONBF, 0);
+
+    ok(ret == 4, "fprintf(stdout) returned %d\n", ret);
+    ok(!pos, "expected stdout to be buffered\n");
+
+    dup_fd = _dup(STDERR_FILENO);
+    ok(dup_fd != -1, "_dup failed\n");
+
+    file = freopen("std_stream_test.tmp", "w", stderr);
+    ok(file != NULL, "freopen failed\n");
+
+    ret = fprintf(stderr, "test");
+    ok(ret == 4, "fprintf(stderr) returned %d\n", ret);
+    pos = _telli64(STDERR_FILENO);
+    if (broken(!GetProcAddress(GetModuleHandleA("ucrtbase"), "__CxxFrameHandler4") && !pos))
+        trace("stderr is buffered\n");
+    else
+        todo_wine
+        ok(pos == 4, "expected stderr to be unbuffered (%d)\n", pos);
+
+    fflush(stderr);
+    _dup2(dup_fd, STDERR_FILENO);
+    close(dup_fd);
+
+    dup_fd = _dup(STDIN_FILENO);
+    ok(dup_fd != -1, "_dup failed\n");
+
+    file = freopen("std_stream_test.tmp", "r", stdin);
+    ok(file != NULL, "freopen failed\n");
+
+    ch = 0;
+    ret = fscanf(stdin, "%c", &ch);
+    ok(ret == 1, "fscanf returned %d\n", ret);
+    ok(ch == 't', "ch = 0x%x\n", (unsigned char)ch);
+    pos = _telli64(STDIN_FILENO);
+    ok(pos == 4, "pos = %d\n", pos);
+
+    fflush(stdin);
+    _dup2(dup_fd, STDIN_FILENO);
+    close(dup_fd);
+
+    ok(DeleteFileA("std_stream_test.tmp"), "DeleteFile failed\n");
+}
+
+START_TEST(file)
+{
+    test_std_stream_buffering();
+}