Using a Bitcoin-Qt v0.16.0 ([downloaded from bitcoin page](https://bitcoin.org/bin/bitcoin-core-0.16.0/bitcoin-0.16.0-osx.dmg)) in an macOS High Sierra 10.13.4 

When I start after a fresh install Bitcoin-Qt as a mainnet node and wallet, the wallet prompt that about 203gb is going to be used in my disk
![image](https://user-images.githubusercontent.com/20187136/39899688-ba820bfe-5493-11e8-87d9-460ed5716a02.png)

When I start the node and wallet as testnet, shows the same message about the 203gb disk usage
![image](https://user-images.githubusercontent.com/20187136/39899756-17b31214-5494-11e8-8a57-60e604e74afb.png)

It seems that the second time the message is wrong, due that the testnet database uses about 14gb.
const CMessageHeader::MessageStartChars& MessageStart() const { return pchMessageStart; }
    int GetDefaultPort() const { return nDefaultPort; }
    const CBlock& GenesisBlock() const { return genesis; }
    
    bool DefaultConsistencyChecks() const { return fDefaultConsistencyChecks; }
    
    bool RequireStandard() const { return fRequireStandard; }
    uint64_t PruneAfterHeight() const { return nPruneAfterHeight; }
    
    bool MineBlocksOnDemand() const { return fMineBlocksOnDemand; }
    
    std::string NetworkIDString() const { return strNetworkID; }
    
    bool IsFallbackFeeEnabled() const { return m_fallback_fee_enabled; }
    
    const std::vector<std::string>& DNSSeeds() const { return vSeeds; }
    const std::vector<unsigned char>& Base58Prefix(Base58Type type) const { return base58Prefixes[type]; }
    const std::string& Bech32HRP() const { return bech32_hrp; }
    const std::vector<SeedSpec6>& FixedSeeds() const { return vFixedSeeds; }
    const CCheckpointData& Checkpoints() const { return checkpointData; }
    const ChainTxData& TxData() const { return chainTxData; }
protected:
    CChainParams() {}
    Consensus::Params consensus;
    CMessageHeader::MessageStartChars pchMessageStart;
    int nDefaultPort;
    uint64_t nPruneAfterHeight;
    std::vector<std::string> vSeeds;