Add wapp_str8_from_bytes

tests/str8/test_str8.cc

@@ -612,3 +612,17 @@ TestFuncResult test_str8_join(void) {
 
   return wapp_tester_result(result);
 }
+
+TestFuncResult test_str8_from_bytes(void) {
+  bool result;
+
+  Str8 str      = wapp_str8_buf(1024);
+  Str8 expected = wapp_str8_lit_ro("WAPP");
+  U8Array bytes = wapp_u8_array('W', 'A', 'P', 'P');
+  wapp_str8_from_bytes(&str, &bytes);
+
+  result = str.size == bytes.count * bytes.item_size;
+  result = result && wapp_str8_equal(&str, &expected);
+
+  return wapp_tester_result(result);
+}