Refactored StringBuilder into StringStorage

extras/tests/MemoryPool/StringCopier.cpp

@@ -0,0 +1,45 @@
+// ArduinoJson - arduinojson.org
+// Copyright Benoit Blanchon 2014-2020
+// MIT License
+
+#include <ArduinoJson/StringStorage/StringCopier.hpp>
+#include <catch.hpp>
+
+using namespace ARDUINOJSON_NAMESPACE;
+
+TEST_CASE("StringCopier") {
+  char buffer[4096];
+
+  SECTION("Works when buffer is big enough") {
+    MemoryPool pool(buffer, addPadding(JSON_STRING_SIZE(6)));
+    StringCopier str;
+
+    str.startString(&pool);
+    str.append("hello");
+    str.append('\0');
+
+    REQUIRE(str.isValid() == true);
+    REQUIRE(str.c_str() == std::string("hello"));
+  }
+
+  SECTION("Returns null when too small") {
+    MemoryPool pool(buffer, sizeof(void*));
+    StringCopier str;
+
+    str.startString(&pool);
+    str.append("hello world!");
+
+    REQUIRE(str.isValid() == false);
+  }
+
+  SECTION("Increases size of memory pool") {
+    MemoryPool pool(buffer, addPadding(JSON_STRING_SIZE(6)));
+    StringCopier str;
+
+    str.startString(&pool);
+    str.append('h');
+    str.commit(&pool);
+
+    REQUIRE(1 == pool.size());
+  }
+}