[Tests] check specific validation error in miner tests

BOOST_CHECK_THROW merely checks that some std::runtime_error is
thrown, but not which one.

One example of how this could lead to a test passing when a developer
introduces a consensus bug: the test for the sigops limit assumes
that CreateNewBlock fails with bad-blk-sigops. However it can
also fail with bad-txns-vout-negative, e.g. if a naive developer lowers
BLOCKSUBSIDY to 1*COIN in the test.

BOOST_CHECK_EXCEPTION allows an additional predicate function. This
commit uses this for all exceptions that are checked for in
miner_tets.cpp:
* bad-blk-sigops
* bad-cb-multiple
* bad-txns-inputs-missingorspent
* block-validation-failed

An instance of the CheckRejectInvalid class (for a given validation string)
is passed to BOOST_CHECK_EXCEPTION.

src/test/miner_tests.cpp

@@ -26,6 +26,17 @@
 
 BOOST_FIXTURE_TEST_SUITE(miner_tests, TestingSetup)
 
+// BOOST_CHECK_EXCEPTION predicates to check the specific validation error
+class HasReason {
+public:
+    HasReason(const std::string& reason) : m_reason(reason) {}
+    bool operator() (const std::runtime_error& e) const {
+        return std::string(e.what()).find(m_reason) != std::string::npos;
+    };
+private:
+    const std::string m_reason;
+};
+
 static CFeeRate blockMinFeeRate = CFeeRate(DEFAULT_BLOCK_MIN_TX_FEE);
 
 static BlockAssembler AssemblerForTest(const CChainParams& params) {
@@ -264,7 +275,8 @@ BOOST_AUTO_TEST_CASE(CreateNewBlock_validity)
         mempool.addUnchecked(hash, entry.Fee(LOWFEE).Time(GetTime()).SpendsCoinbase(spendsCoinbase).FromTx(tx));
         tx.vin[0].prevout.hash = hash;
     }
-    BOOST_CHECK_THROW(AssemblerForTest(chainparams).CreateNewBlock(scriptPubKey), std::runtime_error);
+
+    BOOST_CHECK_EXCEPTION(AssemblerForTest(chainparams).CreateNewBlock(scriptPubKey), std::runtime_error, HasReason("bad-blk-sigops"));
     mempool.clear();
 
     tx.vin[0].prevout.hash = txFirst[0]->GetHash();
@@ -304,7 +316,7 @@ BOOST_AUTO_TEST_CASE(CreateNewBlock_validity)
     // orphan in mempool, template creation fails
     hash = tx.GetHash();
     mempool.addUnchecked(hash, entry.Fee(LOWFEE).Time(GetTime()).FromTx(tx));
-    BOOST_CHECK_THROW(AssemblerForTest(chainparams).CreateNewBlock(scriptPubKey), std::runtime_error);
+    BOOST_CHECK_EXCEPTION(AssemblerForTest(chainparams).CreateNewBlock(scriptPubKey), std::runtime_error, HasReason("bad-txns-inputs-missingorspent"));
     mempool.clear();
 
     // child with higher feerate than parent
@@ -332,7 +344,8 @@ BOOST_AUTO_TEST_CASE(CreateNewBlock_validity)
     hash = tx.GetHash();
     // give it a fee so it'll get mined
     mempool.addUnchecked(hash, entry.Fee(LOWFEE).Time(GetTime()).SpendsCoinbase(false).FromTx(tx));
-    BOOST_CHECK_THROW(AssemblerForTest(chainparams).CreateNewBlock(scriptPubKey), std::runtime_error);
+    // Should throw bad-cb-multiple
+    BOOST_CHECK_EXCEPTION(AssemblerForTest(chainparams).CreateNewBlock(scriptPubKey), std::runtime_error, HasReason("bad-cb-multiple"));
     mempool.clear();
 
     // double spend txn pair in mempool, template creation fails
@@ -345,7 +358,7 @@ BOOST_AUTO_TEST_CASE(CreateNewBlock_validity)
     tx.vout[0].scriptPubKey = CScript() << OP_2;
     hash = tx.GetHash();
     mempool.addUnchecked(hash, entry.Fee(HIGHFEE).Time(GetTime()).SpendsCoinbase(true).FromTx(tx));
-    BOOST_CHECK_THROW(AssemblerForTest(chainparams).CreateNewBlock(scriptPubKey), std::runtime_error);
+    BOOST_CHECK_EXCEPTION(AssemblerForTest(chainparams).CreateNewBlock(scriptPubKey), std::runtime_error, HasReason("bad-txns-inputs-missingorspent"));
     mempool.clear();
 
     // subsidy changing
@@ -389,7 +402,8 @@ BOOST_AUTO_TEST_CASE(CreateNewBlock_validity)
     tx.vout[0].nValue -= LOWFEE;
     hash = tx.GetHash();
     mempool.addUnchecked(hash, entry.Fee(LOWFEE).Time(GetTime()).SpendsCoinbase(false).FromTx(tx));
-    BOOST_CHECK_THROW(AssemblerForTest(chainparams).CreateNewBlock(scriptPubKey), std::runtime_error);
+    // Should throw block-validation-failed
+    BOOST_CHECK_EXCEPTION(AssemblerForTest(chainparams).CreateNewBlock(scriptPubKey), std::runtime_error, HasReason("block-validation-failed"));
     mempool.clear();
 
     // Delete the dummy blocks again.