diff --git a/test/test.c b/test/test.c
index 7deff34..940d64e 100644
--- a/test/test.c
+++ b/test/test.c
@@ -3,6 +3,17 @@
 #include <stdlib.h>
 #include <string.h>
 
+#ifdef _WIN32
+#include <direct.h>
+#define MKDIR(path) _mkdir(path)
+#define RMDIR(path) _rmdir(path)
+#else
+#include <sys/stat.h>
+#include <unistd.h>
+#define MKDIR(path) mkdir(path, 0755)
+#define RMDIR(path) rmdir(path)
+#endif
+
 #define CHECK(cond, msg)                                                     \
 	do {                                                                  \
 		if (!(cond)) {                                                \
@@ -13,6 +24,14 @@
 
 static const char *PAK_PATH = "roundtrip.fpk";
 
+static void write_file(const char *path, const char *data)
+{
+	FILE *fp = fopen(path, "wb");
+
+	fwrite(data, 1, strlen(data), fp);
+	fclose(fp);
+}
+
 int main(void)
 {
 	struct fpk_writer *w;
@@ -66,6 +85,45 @@ int main(void)
 	fpk_close(r);
 	remove(PAK_PATH);
 
+	CHECK(MKDIR("adddir_src") == 0, "mkdir(adddir_src) failed");
+	CHECK(MKDIR("adddir_src/nested") == 0, "mkdir(adddir_src/nested) failed");
+	write_file("adddir_src/root.txt", "root");
+	write_file("adddir_src/nested/leaf.txt", "leaf");
+
+	w = fpk_writer_open("adddir.fpk");
+	CHECK(w != NULL, "fpk_writer_open(adddir) failed");
+	CHECK(fpk_writer_add_dir(w, "adddir_src", NULL, NULL) == 0,
+	      "fpk_writer_add_dir failed");
+	CHECK(fpk_writer_finalize(w) == 0, "fpk_writer_finalize(adddir) failed");
+	fpk_writer_close(w);
+
+	r = fpk_open("adddir.fpk");
+	CHECK(r != NULL, "fpk_open(adddir) failed");
+	CHECK(fpk_entry_count(r) == 2, "adddir entry_count mismatch");
+
+	entry = fpk_find(r, "root.txt");
+	CHECK(entry != NULL, "fpk_find(root.txt) failed");
+	data = fpk_read(r, entry, &out_size);
+	CHECK(data != NULL, "fpk_read(root.txt) failed");
+	CHECK(out_size == 4 && memcmp(data, "root", 4) == 0,
+	      "root.txt content mismatch");
+	free(data);
+
+	entry = fpk_find(r, "nested/leaf.txt");
+	CHECK(entry != NULL, "fpk_find(nested/leaf.txt) failed");
+	data = fpk_read(r, entry, &out_size);
+	CHECK(data != NULL, "fpk_read(nested/leaf.txt) failed");
+	CHECK(out_size == 4 && memcmp(data, "leaf", 4) == 0,
+	      "nested/leaf.txt content mismatch");
+	free(data);
+
+	fpk_close(r);
+	remove("adddir.fpk");
+	remove("adddir_src/root.txt");
+	remove("adddir_src/nested/leaf.txt");
+	RMDIR("adddir_src/nested");
+	RMDIR("adddir_src");
+
 	printf("PASS\n");
 	return EXIT_SUCCESS;
 }