diff --git a/tests/stream_buffer.c b/tests/stream_buffer.c
index 95d75b8..ec39286 100644
--- a/tests/stream_buffer.c
+++ b/tests/stream_buffer.c
@@ -19,13 +19,13 @@
 
 static gmio_bool_t gmio_stream_buffer_at_end(void* cookie)
 {
-    const gmio_stream_buffer_t* buff = (const gmio_stream_buffer_t*)cookie;
+    const gmio_ro_buffer_t* buff = (const gmio_ro_buffer_t*)cookie;
     return buff->pos >= buff->len;
 }
 
 static int gmio_stream_buffer_error(void* cookie)
 {
-    const gmio_stream_buffer_t* buff = (const gmio_stream_buffer_t*)cookie;
+    const gmio_ro_buffer_t* buff = (const gmio_ro_buffer_t*)cookie;
     return buff == NULL || buff->pos > buff->len;
 }
 
@@ -33,15 +33,14 @@ static size_t gmio_stream_buffer_read(
         void* cookie, void* ptr, size_t item_size, size_t item_count)
 {
     if (item_size > 0 && item_count > 0) {
-        gmio_stream_buffer_t* buff = (gmio_stream_buffer_t*)cookie;
-        const void* buff_ptr =
-                buff->readonly_ptr != NULL ?
-                    buff->readonly_ptr : buff->readwrite_ptr;
+        gmio_ro_buffer_t* buff = (gmio_ro_buffer_t*)cookie;
+        const void* buff_ptr = buff->ptr;
         const size_t buff_remaining_size = buff->len - buff->pos;
         const size_t wanted_read_size = item_size * item_count;
         const size_t next_read_size =
                 wanted_read_size <= buff_remaining_size ?
-                    wanted_read_size : buff_remaining_size;
+                    wanted_read_size :
+                    buff_remaining_size;
         const size_t next_read_item_count = next_read_size / item_size;
 
         memcpy(ptr,
@@ -59,15 +58,16 @@ static size_t gmio_stream_buffer_write(
         void* cookie, const void* ptr, size_t item_size, size_t item_count)
 {
     if (item_size > 0 && item_count > 0) {
-        gmio_stream_buffer_t* buff = (gmio_stream_buffer_t*)cookie;
+        gmio_rw_buffer_t* buff = (gmio_rw_buffer_t*)cookie;
         const size_t buff_remaining_size = buff->len - buff->pos;
         const size_t wanted_write_size = item_size * item_count;
         const size_t next_write_size =
                 wanted_write_size <= buff_remaining_size ?
-                    wanted_write_size : buff_remaining_size;
+                    wanted_write_size :
+                    buff_remaining_size;
         const size_t next_write_item_count = next_write_size / item_size;
 
-        memcpy((char*)buff->readwrite_ptr + buff->pos,
+        memcpy((char*)buff->ptr + buff->pos,
                ptr,
                next_write_item_count * item_size);
         buff->pos += next_write_item_count * item_size;
@@ -80,32 +80,40 @@ static size_t gmio_stream_buffer_write(
 
 static gmio_streamsize_t gmio_stream_buffer_size(void* cookie)
 {
-    const gmio_stream_buffer_t* buff = (const gmio_stream_buffer_t*)cookie;
+    const gmio_ro_buffer_t* buff = (const gmio_ro_buffer_t*)cookie;
     return buff->len;
 }
 
 static int gmio_stream_buffer_get_pos(void* cookie, gmio_stream_pos_t* pos)
 {
-    gmio_stream_buffer_t* buff = (gmio_stream_buffer_t*)cookie;
+    gmio_ro_buffer_t* buff = (gmio_ro_buffer_t*)cookie;
     memcpy(&pos->cookie[0], &buff->pos, sizeof(size_t));
     return 0;
 }
 
 static int gmio_stream_buffer_set_pos(void* cookie, const gmio_stream_pos_t* pos)
 {
-    gmio_stream_buffer_t* buff = (gmio_stream_buffer_t*)cookie;
+    gmio_ro_buffer_t* buff = (gmio_ro_buffer_t*)cookie;
     memcpy(&buff->pos, &pos->cookie[0], sizeof(size_t));
     return 0;
 }
 
-void gmio_stream_set_buffer(gmio_stream_t *stream, gmio_stream_buffer_t* buff)
+gmio_stream_t gmio_istream_buffer(gmio_ro_buffer_t* buff)
 {
-    stream->cookie = buff;
-    stream->func_at_end = gmio_stream_buffer_at_end;
-    stream->func_error = gmio_stream_buffer_error;
-    stream->func_read = gmio_stream_buffer_read;
-    stream->func_write = gmio_stream_buffer_write;
-    stream->func_size = gmio_stream_buffer_size;
-    stream->func_get_pos = gmio_stream_buffer_get_pos;
-    stream->func_set_pos = gmio_stream_buffer_set_pos;
+    gmio_stream_t stream = {0};
+    stream.cookie = buff;
+    stream.func_at_end = gmio_stream_buffer_at_end;
+    stream.func_error = gmio_stream_buffer_error;
+    stream.func_read = gmio_stream_buffer_read;
+    stream.func_size = gmio_stream_buffer_size;
+    stream.func_get_pos = gmio_stream_buffer_get_pos;
+    stream.func_set_pos = gmio_stream_buffer_set_pos;
+    return stream;
+}
+
+gmio_stream_t gmio_stream_buffer(gmio_rw_buffer_t* buff)
+{
+    gmio_stream_t stream = gmio_istream_buffer((gmio_ro_buffer_t*)buff);
+    stream.func_write = gmio_stream_buffer_write;
+    return stream;
 }
diff --git a/tests/stream_buffer.h b/tests/stream_buffer.h
index c0d7db3..4b65cee 100644
--- a/tests/stream_buffer.h
+++ b/tests/stream_buffer.h
@@ -18,15 +18,25 @@
 
 #include "../src/gmio_core/stream.h"
 
-struct gmio_stream_buffer
+/* Read-only buffer */
+struct gmio_ro_buffer
 {
-    const void* readonly_ptr;
-    void* readwrite_ptr;
+    const void* ptr;
     size_t len;
     size_t pos;
 };
-typedef struct gmio_stream_buffer gmio_stream_buffer_t;
+typedef struct gmio_ro_buffer gmio_ro_buffer_t;
 
-void gmio_stream_set_buffer(gmio_stream_t* stream, gmio_stream_buffer_t* buff);
+/* Read/write buffer */
+struct gmio_rw_buffer
+{
+    void* ptr;
+    size_t len;
+    size_t pos;
+};
+typedef struct gmio_rw_buffer gmio_rw_buffer_t;
+
+gmio_stream_t gmio_istream_buffer(gmio_ro_buffer_t* buff);
+gmio_stream_t gmio_iostream_buffer(gmio_rw_buffer_t* buff);
 
 #endif /* GMIO_STREAM_BUFFER_H */
diff --git a/tests/test_core_internal.c b/tests/test_core_internal.c
index eb523b3..90c8d18 100644
--- a/tests/test_core_internal.c
+++ b/tests/test_core_internal.c
@@ -124,22 +124,21 @@ const char* test_internal__fast_atof()
     return NULL;
 }
 
+static const char test_internal__gmio_fast_atof__fstr[] = "1234.567E05";
 const char* test_internal__gmio_fast_atof()
 {
-    const char fstr[] = "1234.567E05";
-    const float f1 = fast_atof(fstr);
+    const float f1 = fast_atof(test_internal__gmio_fast_atof__fstr);
 
     {
         char strbuff[2048] = {0};
         gmio_stringstream_t it = {0};
-        gmio_stream_buffer_t streambuff = {0};
-        gmio_stream_t stream = {0};
+        gmio_ro_buffer_t streambuff = {
+            &test_internal__gmio_fast_atof__fstr[0],
+            sizeof(test_internal__gmio_fast_atof__fstr) - 1,
+            0 };
+        gmio_stream_t stream = gmio_istream_buffer(&streambuff);
         float f2;
 
-        streambuff.readonly_ptr = &fstr[0];
-        streambuff.len = sizeof(fstr) - 1;
-        gmio_stream_set_buffer(&stream, &streambuff);
-
         it.stream = &stream;
         it.strbuff.ptr = &strbuff[0];
         it.strbuff.max_len = sizeof(strbuff) - 1;
@@ -176,16 +175,19 @@ const char* test_internal__safe_cast()
     return NULL;
 }
 
+static const char test_internal__stringstream__text[] =
+        "Une    citation,\to je crois qu'elle est de moi :"
+        "Parfois le chemin est rude.\n"
+        "pi : 3.1415926535897932384626433832795";
+
 const char* test_internal__stringstream()
 {
-    const char text[] =
-            "Une    citation,\to je crois qu'elle est de moi :"
-            "Parfois le chemin est rude.\n"
-            "pi : 3.1415926535897932384626433832795";
-
     {
-        gmio_stream_buffer_t buff = {0};
-        gmio_stream_t stream = {0};
+        gmio_ro_buffer_t buff = {
+            &test_internal__stringstream__text[0],
+            sizeof(test_internal__stringstream__text) - 1,
+            0 };
+        gmio_stream_t stream = gmio_istream_buffer(&buff);
 
         char small_fwd_it_str[4];
         char fwd_it_str[32];
@@ -194,11 +196,6 @@ const char* test_internal__stringstream()
         char copy_str[128];
         gmio_string_t copy_strbuff;
 
-        buff.readonly_ptr = text;
-        buff.len = strlen(text);
-        buff.pos = 0;
-        gmio_stream_set_buffer(&stream, &buff);
-
         fwd_it.stream = &stream;
         fwd_it.strbuff.ptr = fwd_it_str;
         fwd_it.strbuff.max_len = sizeof(fwd_it_str);
@@ -246,8 +243,11 @@ const char* test_internal__stringstream()
     }
 
     {
-        gmio_stream_buffer_t buff = {0};
-        gmio_stream_t stream = {0};
+        gmio_ro_buffer_t buff = {
+            &test_internal__stringstream__text[0],
+            sizeof(test_internal__stringstream__text) - 1,
+            0 };
+        gmio_stream_t stream = gmio_istream_buffer(&buff);
 
         char fwd_it_str[32];
         gmio_stringstream_t fwd_it = {0};
@@ -255,11 +255,6 @@ const char* test_internal__stringstream()
         char copy_str[128];
         gmio_string_t copy_strbuff;
 
-        buff.readonly_ptr = text;
-        buff.len = strlen(text);
-        buff.pos = 0;
-        gmio_stream_set_buffer(&stream, &buff);
-
         fwd_it.stream = &stream;
         fwd_it.strbuff.ptr = fwd_it_str;
         fwd_it.strbuff.max_len = sizeof(fwd_it_str);