[test] move mining helper functions into test library

src/test/util/mining.cpp

@@ -0,0 +1,51 @@
+// Copyright (c) 2019 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include <test/util/mining.h>
+
+#include <chainparams.h>
+#include <consensus/merkle.h>
+#include <key_io.h>
+#include <miner.h>
+#include <pow.h>
+#include <script/standard.h>
+#include <validation.h>
+
+CTxIn generatetoaddress(const std::string& address)
+{
+    const auto dest = DecodeDestination(address);
+    assert(IsValidDestination(dest));
+    const auto coinbase_script = GetScriptForDestination(dest);
+
+    return MineBlock(coinbase_script);
+}
+
+CTxIn MineBlock(const CScript& coinbase_scriptPubKey)
+{
+    auto block = PrepareBlock(coinbase_scriptPubKey);
+
+    while (!CheckProofOfWork(block->GetHash(), block->nBits, Params().GetConsensus())) {
+        ++block->nNonce;
+        assert(block->nNonce);
+    }
+
+    bool processed{ProcessNewBlock(Params(), block, true, nullptr)};
+    assert(processed);
+
+    return CTxIn{block->vtx[0]->GetHash(), 0};
+}
+
+std::shared_ptr<CBlock> PrepareBlock(const CScript& coinbase_scriptPubKey)
+{
+    auto block = std::make_shared<CBlock>(
+        BlockAssembler{Params()}
+            .CreateNewBlock(coinbase_scriptPubKey)
+            ->block);
+
+    LOCK(cs_main);
+    block->nTime = ::ChainActive().Tip()->GetMedianTimePast() + 1;
+    block->hashMerkleRoot = BlockMerkleRoot(*block);
+
+    return block;
+}