ntdll/tests: Add tests for linking a file to the same name.

dlls/ntdll/tests/file.c

@@ -2759,6 +2759,36 @@ static void test_file_link_information(void)
     HeapFree( GetProcessHeap(), 0, fli );
     delete_object( oldpath );
     delete_object( newpath );
+
+    /* oldpath == newpath */
+    res = GetTempFileNameW( tmp_path, fooW, 0, oldpath );
+    ok( res != 0, "failed to create temp file\n" );
+    handle = CreateFileW( oldpath, GENERIC_WRITE | DELETE, 0, NULL, CREATE_ALWAYS, 0, 0 );
+    ok( handle != INVALID_HANDLE_VALUE, "CreateFileW failed\n" );
+
+    pRtlDosPathNameToNtPathName_U( oldpath, &name_str, NULL, NULL );
+    fli = HeapAlloc( GetProcessHeap(), 0, sizeof(FILE_RENAME_INFORMATION) + name_str.Length );
+    fli->ReplaceIfExists = FALSE;
+    fli->RootDirectory = NULL;
+    fli->FileNameLength = name_str.Length;
+    memcpy( fli->FileName, name_str.Buffer, name_str.Length );
+    pRtlFreeUnicodeString( &name_str );
+
+    U(io).Status = 0xdeadbeef;
+    res = pNtSetInformationFile( handle, &io, fli, sizeof(FILE_LINK_INFORMATION) + fli->FileNameLength, FileLinkInformation );
+    todo_wine ok( U(io).Status == 0xdeadbeef, "got io status %#x\n", U(io).Status );
+    ok( res == STATUS_OBJECT_NAME_COLLISION, "got status %x\n", res );
+
+    fli->ReplaceIfExists = TRUE;
+    U(io).Status = 0xdeadbeef;
+    res = pNtSetInformationFile( handle, &io, fli, sizeof(FILE_LINK_INFORMATION) + fli->FileNameLength, FileLinkInformation );
+    todo_wine ok( U(io).Status == STATUS_SUCCESS, "got io status %#x\n", U(io).Status );
+    todo_wine ok( res == STATUS_SUCCESS, "got status %x\n", res );
+    ok( GetFileAttributesW( oldpath ) != INVALID_FILE_ATTRIBUTES, "file should exist\n" );
+
+    CloseHandle( handle );
+    HeapFree( GetProcessHeap(), 0, fli );
+    delete_object( oldpath );
 }
 
 static void test_file_both_information(void)