Method checkReadString

Tests/EncoderTests.cc:123–128

    }

    void checkReadString(const char *str) {
        auto v = Value::fromData(result);
        REQUIRE(v != nullptr);
        REQUIRE(v->type() == kString);
        REQUIRE(v->asString() == slice(str, strlen(str)));
    }

    const Array* checkArray(uint32_t count) {
        auto v = Value::fromData(result);