diff --git a/tests/src/string/main.c b/tests/src/string/main.c
index 5c9f26c..4eb7e31 100644
--- a/tests/src/string/main.c
+++ b/tests/src/string/main.c
@@ -3,6 +3,59 @@
 
 #include "plug.h"
 
+
+static vtype_string string_random(unsigned int n) {
+    vtype_string x;
+
+    if (random_boolean()) {
+        x.buffer = random_utf8_cstring(n);
+    } else x.buffer = random_ascii_cstring(n);
+
+    return x;
+}
+
+static void string_concat_random(vtype_string* x, unsigned int n) {
+    char* v;
+
+    if (random_boolean()) {
+        v = random_utf8_cstring(n);
+    } else v = random_ascii_cstring(n);
+
+    string_concat(x, v);
+    free(v);
+}
+
+static void string_info(vtype_string* x) {
+    printf("\e[36mString consists of \e[m\e[32m%lu\e[m\e[36m utf8 chars (\e[m\e[32m%lu bytes\e[m\e[36m)\e[m\n", string_size(x), string_nmemb(x));
+}
+
+static void string_print(const vtype_string* x, const char* prefix) {
+    if (!prefix) puts("\e[36mString content:\e[m\n");
+    else printf("\e[36mString %s content:\e[m\n\n", prefix);
+    printf("\e[33m%s\e[m\n", x->buffer);
+    put_separator();
+}
+
+
 int main(int argc, char** argv) {
     test_init(argc, argv);
+    vtype_string x;
+
+    x = string_random(31);
+    string_print(&x, "(part 1)");
+
+    string_concat(&x, '\n');
+    string_concat_random(&x, 31);
+
+    {
+        void* hack = string_at(&x, 32);
+        string_print((void*)&hack, "(part 2)");
+    }
+
+    string_info(&x);
+    string_print(&x, "concatenated");
+
+
+
+    string_free(&x);
 }
diff --git a/tests/src/string/plug.h b/tests/src/string/plug.h
index 257d6e9..c144b5e 100644
--- a/tests/src/string/plug.h
+++ b/tests/src/string/plug.h
@@ -1,6 +1,8 @@
 /* This software is licensed by the MIT License, see LICENSE file */
 /*                                Copyright © 2022 Gregory Lirent */
 
+#include <stdlib.h>
+#include "../../../modules/libunic/include.h"
 #include "../../../include/extra/string.h"
 
 #include "../../include/random.h"
@@ -21,3 +23,27 @@ int array_compare (const vtype_array*  s0, const vtype_array*  s1) { return rand
 int list_compare  (const vtype_list*   s0, const vtype_list*   s1) { return random_int8(); }
 int map_compare   (const vtype_map*    s0, const vtype_map*    s1) { return random_int8(); }
 int vset_compare  (const vtype_set*    s0, const vtype_set*    s1) { return random_int8(); }
+
+static char* random_ascii_cstring(size_t size) {
+    char* v = malloc(size + 1);
+    char* p = v;
+
+    while (size--) {
+        *(p++) = random_ascii_char();
+    }
+    *p = 0;
+
+    return v;
+}
+
+static char* random_utf8_cstring(size_t size) {
+    char* v = malloc(size * 4 + 1);
+    char* p = v;
+
+    while (size--) {
+        p = tochar_unicode(p, random_unicode_symbol());
+    }
+
+    *p = 0;
+    return v;
+}