Reported here: https://github.com/bitcoin/bitcoin/pull/10244#issuecomment-378035305

Travis log here: https://travis-ci.org/bitcoin/bitcoin/jobs/361243719#L2810

Note the JSON exception:

```
test_framework.authproxy.JSONRPCException: The mempool was not loaded yet (-1) 
```

That exception was introduced here: https://github.com/bitcoin/bitcoin/commit/cb1e319fe9e198c9c5cf5236fe9af5a3d748b9e8#diff-a0c8f511d90e83aa9b5857e819ced344R1617

cc @jtimon 
void check(const CCoinsViewCache *pcoins) const;
    void setSanityCheck(double dFrequency = 1.0) { LOCK(cs); nCheckFrequency = static_cast<uint32_t>(dFrequency * 4294967295.0); }
    
    
    
    
    
    
    
    void addUnchecked(const CTxMemPoolEntry& entry, bool validFeeEstimate = true) EXCLUSIVE_LOCKS_REQUIRED(cs, cs_main);
    void addUnchecked(const CTxMemPoolEntry& entry, setEntries& setAncestors, bool validFeeEstimate = true) EXCLUSIVE_LOCKS_REQUIRED(cs, cs_main);
    void removeRecursive(const CTransaction &tx, MemPoolRemovalReason reason = MemPoolRemovalReason::UNKNOWN);
    void removeForReorg(const CCoinsViewCache *pcoins, unsigned int nMemPoolHeight, int flags) EXCLUSIVE_LOCKS_REQUIRED(cs_main);
    void removeConflicts(const CTransaction &tx) EXCLUSIVE_LOCKS_REQUIRED(cs);
    void removeForBlock(const std::vector<CTransactionRef>& vtx, unsigned int nBlockHeight);
    void clear();
    void _clear() EXCLUSIVE_LOCKS_REQUIRED(cs); 
    bool CompareDepthAndScore(const uint256& hasha, const uint256& hashb);
    void queryHashes(std::vector<uint256>& vtxid) const;
    bool isSpent(const COutPoint& outpoint) const;
    unsigned int GetTransactionsUpdated() const;
    void AddTransactionsUpdated(unsigned int n);
    /**
     * Check that none of this transactions inputs are in the mempool, and thus
     * the tx is not dependent on other mempool transactions to be included in a block.
     */
    bool HasNoInputsOf(const CTransaction& tx) const;
    
    void PrioritiseTransaction(const uint256& hash, const CAmount& nFeeDelta);
    void ApplyDelta(const uint256 hash, CAmount &nFeeDelta) const;