Merge pull request #2559 from benjaminion/lll-contract-test-erc20

LLL: whole contract tests for ERC20 token.

2 files changed, 652 insertions, 0 deletions

diff --git a/test/boostTest.cpp b/test/boostTest.cpp
index 6fc1c925..0a020187 100644
--- a/test/boostTest.cpp
+++ b/test/boostTest.cpp
@@ -49,6 +49,7 @@ test_suite* init_unit_test_suite( int /*argc*/, char* /*argv*/[] )
 			"SolidityAuctionRegistrar",
 			"SolidityFixedFeeRegistrar",
 			"SolidityWallet",
+			"LLLERC20",
 			"LLLEndToEndTest",
 			"GasMeterTests",
 			"SolidityEndToEndTest",
diff --git a/test/contracts/LLL_ERC20.cpp b/test/contracts/LLL_ERC20.cpp
new file mode 100644
index 00000000..3ee1aa98
--- /dev/null
+++ b/test/contracts/LLL_ERC20.cpp
@@ -0,0 +1,651 @@
+/*
+	This file is part of solidity.
+
+	solidity is free software: you can redistribute it and/or modify
+	it under the terms of the GNU General Public License as published by
+	the Free Software Foundation, either version 3 of the License, or
+	(at your option) any later version.
+
+	solidity is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+	GNU General Public License for more details.
+
+	You should have received a copy of the GNU General Public License
+	along with solidity.  If not, see <http://www.gnu.org/licenses/>.
+*/
+/**
+ * @author Ben Edgington <ben@benjaminion.xyz>
+ * @date 2017
+ * Tests for an ERC20 token implementation written in LLL
+ */
+
+#include <string>
+#include <boost/test/unit_test.hpp>
+#include <test/liblll/ExecutionFramework.h>
+#include <liblll/Compiler.h>
+
+#define TOKENSUPPLY   100000
+#define TOKENDECIMALS 2
+#define TOKENSYMBOL   "BEN"
+#define TOKENNAME     "Ben Token"
+#define ACCOUNT(n)    h256(account(n), h256::AlignRight)
+#define SUCCESS       encodeArgs(1)
+
+using namespace std;
+using namespace dev::eth;
+
+namespace dev
+{
+namespace lll
+{
+namespace test
+{
+
+namespace
+{
+
+static char const* erc20Code = R"DELIMITER(
+(seq
+
+  ;; --------------------------------------------------------------------------
+  ;; CONSTANTS
+
+  ;; Token parameters.
+  ;;   0x40 is a "magic number" - the text of the string is placed here
+  ;;   when returning the string to the caller. See return-string below.
+  (def 'token-name-string   (lit 0x40 "Ben Token"))
+  (def 'token-symbol-string (lit 0x40 "BEN"))
+  (def 'token-decimals 2)
+  (def 'token-supply 100000) ; 1000.00 total tokens
+
+  ;; Booleans
+  (def 'false 0)
+  (def 'true  1)
+
+  ;; Memory layout.
+  (def 'mem-ret    0x00) ; Fixed due to compiler macro for return.
+  (def 'mem-func   0x00) ; No conflict with mem-ret, so re-use.
+  (def 'mem-keccak 0x00) ; No conflict with mem-func or mem-ret, so re-use.
+  (def 'scratch0   0x20)
+  (def 'scratch1   0x40)
+
+  ;; Precomputed function IDs.
+  (def 'get-name         0x06fdde03) ; name()
+  (def 'get-symbol       0x95d89b41) ; symbol()
+  (def 'get-decimals     0x313ce567) ; decimals()
+  (def 'get-total-supply 0x18160ddd) ; totalSupply()
+  (def 'get-balance-of   0x70a08231) ; balanceOf(address)
+  (def 'transfer         0xa9059cbb) ; transfer(address,uint256)
+  (def 'transfer-from    0x23b872dd) ; transferFrom(address,address,uint256)
+  (def 'approve          0x095ea7b3) ; approve(address,uint256)
+  (def 'get-allowance    0xdd62ed3e) ; allowance(address,address)
+
+  ;; Event IDs
+  (def 'transfer-event-id ; Transfer(address,address,uint256)
+    0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef)
+
+  (def 'approval-event-id ; Approval(address,address,uint256)
+    0x8c5be1e5ebec7d5bd14f71427d1e84f3dd0314c0f7b2291e5b200ac8c7c3b925)
+
+  ;; --------------------------------------------------------------------------
+  ;; UTILITIES
+
+  ;; --------------------------------------------------------------------------
+  ;;  The following define the key data-structures:
+  ;;    - balance(addr) => value
+  ;;    - allowance(addr,addr) => value
+
+  ;; Balances are stored at s[owner_addr].
+  (def 'balance (address) address)
+
+  ;; Allowances are stored at s[owner_addr + keccak256(spender_addr)]
+  ;;   We use a crypto function here to avoid any situation where
+  ;;   approve(me, spender) can be abused to do approve(target, me).
+  (def 'allowance (owner spender)
+    (seq
+      (mstore mem-keccak spender)
+      (keccak256 mem-keccak 0x20)))
+
+  ;; --------------------------------------------------------------------------
+  ;; For convenience we have macros to refer to function arguments
+
+  (def 'arg1 (calldataload 0x04))
+  (def 'arg2 (calldataload 0x24))
+  (def 'arg3 (calldataload 0x44))
+
+  ;; --------------------------------------------------------------------------
+  ;; Revert is a soft return that does not consume the remaining gas.
+  ;;   We use it when rejecting invalid user input.
+  ;;
+  ;; Note: The REVERT opcode will be implemented in Metropolis (EIP 140).
+  ;;   Meanwhile it just causes an invalid instruction exception (similar
+  ;;   to a "throw" in Solidity).  When fully implemented, Revert could be
+  ;;   use to return error codes, or even messages.
+
+  (def 'revert () (revert 0 0))
+
+  ;; --------------------------------------------------------------------------
+  ;; Macro for returning string names.
+  ;;   Compliant with the ABI format for strings.
+
+  (def 'return-string (string-literal)
+    (seq
+      (mstore 0x00 0x20)           ; Points to our string's memory location
+      (mstore 0x20 string-literal) ; Length. String itself is copied to 0x40.
+      (return 0x00 (& (+ (mload 0x20) 0x5f) (~ 0x1f)))))
+                                   ; Round return up to 32 byte boundary
+
+  ;; --------------------------------------------------------------------------
+  ;; Convenience macro for raising Events
+
+  (def 'event3 (id addr1 addr2 value)
+    (seq
+      (mstore scratch0 value)
+      (log3 scratch0 0x20 id addr1 addr2)))
+
+  ;; --------------------------------------------------------------------------
+  ;; Determines whether the stored function ID matches a known
+  ;;   function hash and executes <code-body> if so.
+  ;; @param function-hash The four-byte hash of a known function signature.
+  ;; @param code-body The code to run in the case of a match.
+
+  (def 'function (function-hash code-body)
+    (when (= (mload mem-func) function-hash)
+      code-body))
+
+  ;; --------------------------------------------------------------------------
+  ;; Gets the function ID and stores it in memory for reference.
+  ;;   The function ID is in the leftmost four bytes of the call data.
+
+  (def 'uses-functions
+    (mstore
+      mem-func
+      (shr (calldataload 0x00) 224)))
+
+  ;; --------------------------------------------------------------------------
+  ;; GUARDS
+
+  ;; --------------------------------------------------------------------------
+  ;; Checks that ensure that each function is called with the right
+  ;;   number of arguments. For one thing this addresses the "ERC20
+  ;;   short address attack". For another, it stops me making
+  ;;   mistakes while testing. We use these only on the non-constant functions.
+
+  (def 'has-one-arg    (unless (= 0x24 (calldatasize)) (revert)))
+  (def 'has-two-args   (unless (= 0x44 (calldatasize)) (revert)))
+  (def 'has-three-args (unless (= 0x64 (calldatasize)) (revert)))
+
+  ;; --------------------------------------------------------------------------
+  ;; Check that addresses have only 160 bits and revert if not.
+  ;;   We use these input type-checks on the non-constant functions.
+
+  (def 'is-address (addr)
+    (when
+      (shr addr 160)
+      (revert)))
+
+  ;; --------------------------------------------------------------------------
+  ;; Check that transfer values are smaller than total supply and
+  ;;   revert if not. This should effectively exclude negative values.
+
+  (def 'is-value (value)
+    (when (> value token-supply) (revert)))
+
+  ;; --------------------------------------------------------------------------
+  ;; Will revert if sent any Ether. We use the macro immediately so as
+  ;;   to abort if sent any Ether during contract deployment.
+
+  (def 'not-payable
+    (when (callvalue) (revert)))
+
+  not-payable
+
+  ;; --------------------------------------------------------------------------
+  ;; INITIALISATION
+  ;;
+  ;; Assign all tokens initially to the owner of the contract.
+
+  (sstore (balance (caller)) token-supply)
+
+  ;; --------------------------------------------------------------------------
+  ;; CONTRACT CODE
+
+  (returnlll
+    (seq not-payable uses-functions
+
+      ;; ----------------------------------------------------------------------
+      ;; Getter for the name of the token.
+      ;; @abi name() constant returns (string)
+      ;; @return The token name as a string.
+
+      (function get-name
+        (return-string token-name-string))
+
+      ;; ----------------------------------------------------------------------
+      ;; Getter for the symbol of the token.
+      ;; @abi symbol() constant returns (string)
+      ;; @return The token symbol as a string.
+
+      (function get-symbol
+        (return-string token-symbol-string))
+
+      ;; ----------------------------------------------------------------------
+      ;; Getter for the number of decimals assigned to the token.
+      ;; @abi decimals() constant returns (uint256)
+      ;; @return The token decimals.
+
+      (function get-decimals
+        (return token-decimals))
+
+      ;; ----------------------------------------------------------------------
+      ;; Getter for the total token supply.
+      ;; @abi totalSupply() constant returns (uint256)
+      ;; @return The token supply.
+
+      (function get-total-supply
+        (return token-supply))
+
+      ;; ----------------------------------------------------------------------
+      ;; Returns the account balance of another account.
+      ;; @abi balanceOf(address) constant returns (uint256)
+      ;; @param owner The address of the account's owner.
+      ;; @return The account balance.
+
+      (function get-balance-of
+        (seq
+
+          (def 'owner arg1)
+
+          (return (sload (balance owner)))))
+
+      ;; ----------------------------------------------------------------------
+      ;; Transfers _value amount of tokens to address _to. The command
+      ;;   should throw if the _from account balance has not enough
+      ;;   tokens to spend.
+      ;; @abi transfer(address, uint256) returns (bool)
+      ;; @param to The account to receive the tokens.
+      ;; @param value The quantity of tokens to transfer.
+      ;; @return Success (true). Other outcomes result in a Revert.
+
+      (function transfer
+        (seq has-two-args (is-address arg1) (is-value arg2)
+
+          (def 'to    arg1)
+          (def 'value arg2)
+
+          (when value ; value == 0 is a no-op
+            (seq
+
+              ;; The caller's balance. Save in memory for efficiency.
+              (mstore scratch0 (sload (balance (caller))))
+
+              ;; Revert if the caller's balance is not sufficient.
+              (when (> value (mload scratch0))
+                (revert))
+
+              ;; Make the transfer
+              ;; It would be good to check invariants (sum of balances).
+              (sstore (balance (caller)) (- (mload scratch0) value))
+              (sstore (balance to) (+ (sload (balance to)) value))
+
+              ;; Event - Transfer(address,address,uint256)
+              (event3 transfer-event-id (caller) to value)))
+
+          (return true)))
+
+      ;; ----------------------------------------------------------------------
+      ;; Send _value amount of tokens from address _from to address _to
+      ;; @abi transferFrom(address,address,uint256) returns (bool)
+      ;; @param from The account to send the tokens from.
+      ;; @param to The account to receive the tokens.
+      ;; @param value The quantity of tokens to transfer.
+      ;; @return Success (true). Other outcomes result in a Revert.
+
+      (function transfer-from
+        (seq has-three-args (is-address arg1) (is-address arg2) (is-value arg3)
+
+          (def 'from  arg1)
+          (def 'to    arg2)
+          (def 'value arg3)
+
+          (when value ; value == 0 is a no-op
+
+            (seq
+
+              ;; Save data to memory for efficiency.
+              (mstore scratch0 (sload (balance from)))
+              (mstore scratch1 (sload (allowance from (caller))))
+
+              ;; Revert if not enough funds, or not enough approved.
+              (when
+                (||
+                  (> value (mload scratch0))
+                  (> value (mload scratch1)))
+                (revert))
+
+              ;; Make the transfer and update allowance.
+              (sstore (balance from) (- (mload scratch0) value))
+              (sstore (balance to) (+ (sload (balance to)) value))
+              (sstore (allowance from (caller)) (- (mload scratch1) value))
+
+              ;; Event - Transfer(address,address,uint256)
+              (event3 transfer-event-id from to value)))
+
+          (return true)))
+
+      ;; ----------------------------------------------------------------------
+      ;; Allows _spender to withdraw from your account multiple times,
+      ;;   up to the _value amount. If this function is called again it
+      ;;   overwrites the current allowance with _value.
+      ;; @abi approve(address,uint256) returns (bool)
+      ;; @param spender The withdrawing account having its limit set.
+      ;; @param value The maximum allowed amount.
+      ;; @return Success (true). Other outcomes result in a Revert.
+
+      (function approve
+        (seq has-two-args (is-address arg1) (is-value arg2)
+
+          (def 'spender arg1)
+          (def 'value   arg2)
+
+          ;; Force users set the allowance to 0 before setting it to
+          ;; another value for the same spender. Prevents this attack:
+          ;; https://docs.google.com/document/d/1YLPtQxZu1UAvO9cZ1O2RPXBbT0mooh4DYKjA_jp-RLM
+          (when
+            (&& value (sload (allowance (caller) spender)))
+            (revert))
+
+          (sstore (allowance (caller) spender) value)
+
+          ;; Event - Approval(address,address,uint256)
+          (event3 approval-event-id (caller) spender value)
+
+          (return true)))
+
+      ;; ----------------------------------------------------------------------
+      ;; Returns the amount which _spender is still allowed to withdraw
+      ;;   from _owner.
+      ;; @abi allowance(address,address) constant returns (uint256)
+      ;; @param owner The owning account.
+      ;; @param spender The withdrawing account.
+      ;; @return The allowed amount remaining.
+
+      (function get-allowance
+        (seq
+
+          (def 'owner   arg1)
+          (def 'spender arg2)
+
+          (return (sload (allowance owner spender)))))
+
+      ;; ----------------------------------------------------------------------
+      ;; Fallback: No functions matched the function ID provided.
+
+      (revert)))
+  )
+)DELIMITER";
+
+static unique_ptr<bytes> s_compiledErc20;
+
+class LLLERC20TestFramework: public LLLExecutionFramework
+{
+protected:
+	void deployErc20()
+	{
+		if (!s_compiledErc20)
+		{
+			vector<string> errors;
+			s_compiledErc20.reset(new bytes(compileLLL(erc20Code, false, &errors)));
+			BOOST_REQUIRE(errors.empty());
+		}
+		sendMessage(*s_compiledErc20, true);
+		BOOST_REQUIRE(!m_output.empty());
+	}
+
+};
+
+}
+
+// Test suite for an ERC20 contract written in LLL.
+BOOST_FIXTURE_TEST_SUITE(LLLERC20, LLLERC20TestFramework)
+
+BOOST_AUTO_TEST_CASE(creation)
+{
+	deployErc20();
+
+	// All tokens are initially assigned to the contract creator.
+	BOOST_CHECK(callContractFunction("balanceOf(address)", ACCOUNT(0)) == encodeArgs(TOKENSUPPLY));
+}
+
+BOOST_AUTO_TEST_CASE(constants)
+{
+	deployErc20();
+
+	BOOST_CHECK(callContractFunction("totalSupply()") == encodeArgs(TOKENSUPPLY));
+	BOOST_CHECK(callContractFunction("decimals()") == encodeArgs(TOKENDECIMALS));
+	BOOST_CHECK(callContractFunction("symbol()") == encodeDyn(string(TOKENSYMBOL)));
+	BOOST_CHECK(callContractFunction("name()") == encodeDyn(string(TOKENNAME)));
+}
+
+BOOST_AUTO_TEST_CASE(send_value)
+{
+	deployErc20();
+
+	// Send value to the contract. Should always fail.
+	m_sender = account(0);
+	auto contractBalance = balanceAt(m_contractAddress);
+
+	// Fallback: check value is not transferred.
+	BOOST_CHECK(callFallbackWithValue(42) != SUCCESS);
+	BOOST_CHECK(balanceAt(m_contractAddress) == contractBalance);
+
+	// Transfer: check nothing happened.
+	BOOST_CHECK(callContractFunctionWithValue("transfer(address,uint256)", ACCOUNT(1), 100, 42) != SUCCESS);
+	BOOST_CHECK(balanceAt(m_contractAddress) == contractBalance);
+	BOOST_CHECK(callContractFunction("balanceOf(address)", ACCOUNT(1)) == encodeArgs(0));
+	BOOST_CHECK(callContractFunction("balanceOf(address)", ACCOUNT(0)) == encodeArgs(TOKENSUPPLY));
+}
+
+BOOST_AUTO_TEST_CASE(transfer)
+{
+	deployErc20();
+
+	// Transfer 100 tokens from account(0) to account(1).
+	int transfer = 100;
+	m_sender = account(0);
+	BOOST_CHECK(callContractFunction("transfer(address,uint256)", ACCOUNT(1), u256(transfer)) == SUCCESS);
+	BOOST_CHECK(callContractFunction("balanceOf(address)", ACCOUNT(0)) == encodeArgs(TOKENSUPPLY - transfer));
+	BOOST_CHECK(callContractFunction("balanceOf(address)", ACCOUNT(1)) == encodeArgs(transfer));
+}
+
+BOOST_AUTO_TEST_CASE(transfer_from)
+{
+	deployErc20();
+
+	// Approve account(1) to transfer up to 1000 tokens from account(0).
+	int allow = 1000;
+	m_sender = account(0);
+	BOOST_REQUIRE(callContractFunction("approve(address,uint256)", ACCOUNT(1), u256(allow)) == SUCCESS);
+	BOOST_REQUIRE(callContractFunction("allowance(address,address)", ACCOUNT(0), ACCOUNT(1)) == encodeArgs(allow));
+
+	// Send account(1) some ether for gas.
+	sendEther(account(1), 1000 * ether);
+	BOOST_REQUIRE(balanceAt(account(1)) >= 1000 * ether);
+
+	// Transfer 300 tokens from account(0) to account(2); check that the allowance decreases.
+	int transfer = 300;
+	m_sender = account(1);
+	BOOST_REQUIRE(callContractFunction("transferFrom(address,address,uint256)", ACCOUNT(0), ACCOUNT(2), u256(transfer)) == SUCCESS);
+	BOOST_CHECK(callContractFunction("balanceOf(address)", ACCOUNT(2)) == encodeArgs(transfer));
+	BOOST_CHECK(callContractFunction("balanceOf(address)", ACCOUNT(0)) == encodeArgs(TOKENSUPPLY - transfer));
+	BOOST_CHECK(callContractFunction("allowance(address,address)", ACCOUNT(0), ACCOUNT(1)) == encodeArgs(allow - transfer));
+}
+
+BOOST_AUTO_TEST_CASE(transfer_event)
+{
+	deployErc20();
+
+	// Transfer 1000 tokens from account(0) to account(1).
+	int transfer = 1000;
+	m_sender = account(0);
+	BOOST_REQUIRE(callContractFunction("transfer(address,uint256)", ACCOUNT(1), u256(transfer)) == SUCCESS);
+
+	// Check that a Transfer event was recorded and contents are correct.
+	BOOST_REQUIRE(m_logs.size() == 1);
+	BOOST_CHECK(m_logs[0].data == encodeArgs(transfer));
+	BOOST_REQUIRE(m_logs[0].topics.size() == 3);
+	BOOST_CHECK(m_logs[0].topics[0] == keccak256(string("Transfer(address,address,uint256)")));
+	BOOST_CHECK(m_logs[0].topics[1] == ACCOUNT(0));
+	BOOST_CHECK(m_logs[0].topics[2] == ACCOUNT(1));
+}
+
+BOOST_AUTO_TEST_CASE(transfer_zero_no_event)
+{
+	deployErc20();
+
+	// Transfer 0 tokens from account(0) to account(1). This is a no-op.
+	int transfer = 0;
+	m_sender = account(0);
+	BOOST_REQUIRE(callContractFunction("transfer(address,uint256)", ACCOUNT(1), u256(transfer)) == SUCCESS);
+
+	// Check that no Event was recorded.
+	BOOST_CHECK(m_logs.size() == 0);
+
+	// Check that balances have not changed.
+	BOOST_CHECK(callContractFunction("balanceOf(address)", ACCOUNT(0)) == encodeArgs(TOKENSUPPLY - transfer));
+	BOOST_CHECK(callContractFunction("balanceOf(address)", ACCOUNT(1)) == encodeArgs(transfer));
+}
+
+BOOST_AUTO_TEST_CASE(approval_and_transfer_events)
+{
+	deployErc20();
+
+	// Approve account(1) to transfer up to 10000 tokens from account(0).
+	int allow = 10000;
+	m_sender = account(0);
+	BOOST_REQUIRE(callContractFunction("approve(address,uint256)", ACCOUNT(1), u256(allow)) == SUCCESS);
+
+	// Check that an Approval event was recorded and contents are correct.
+	BOOST_REQUIRE(m_logs.size() == 1);
+	BOOST_CHECK(m_logs[0].data == encodeArgs(allow));
+	BOOST_REQUIRE(m_logs[0].topics.size() == 3);
+	BOOST_CHECK(m_logs[0].topics[0] == keccak256(string("Approval(address,address,uint256)")));
+	BOOST_CHECK(m_logs[0].topics[1] == ACCOUNT(0));
+	BOOST_CHECK(m_logs[0].topics[2] == ACCOUNT(1));
+
+	// Send account(1) some ether for gas.
+	sendEther(account(1), 1000 * ether);
+	BOOST_REQUIRE(balanceAt(account(1)) >= 1000 * ether);
+
+	// Transfer 3000 tokens from account(0) to account(2); check that the allowance decreases.
+	int transfer = 3000;
+	m_sender = account(1);
+	BOOST_REQUIRE(callContractFunction("transferFrom(address,address,uint256)", ACCOUNT(0), ACCOUNT(2), u256(transfer)) == SUCCESS);
+
+	// Check that a Transfer event was recorded and contents are correct.
+	BOOST_REQUIRE(m_logs.size() == 1);
+	BOOST_CHECK(m_logs[0].data == encodeArgs(transfer));
+	BOOST_REQUIRE(m_logs[0].topics.size() == 3);
+	BOOST_CHECK(m_logs[0].topics[0] == keccak256(string("Transfer(address,address,uint256)")));
+	BOOST_CHECK(m_logs[0].topics[1] == ACCOUNT(0));
+	BOOST_CHECK(m_logs[0].topics[2] == ACCOUNT(2));
+}
+
+BOOST_AUTO_TEST_CASE(invalid_transfer_1)
+{
+	deployErc20();
+
+	// Transfer more than the total supply; ensure nothing changes.
+	int transfer = TOKENSUPPLY + 1;
+	m_sender = account(0);
+	BOOST_CHECK(callContractFunction("transfer(address,uint256)", ACCOUNT(1), u256(transfer)) != SUCCESS);
+	BOOST_CHECK(callContractFunction("balanceOf(address)", ACCOUNT(0)) == encodeArgs(TOKENSUPPLY));
+	BOOST_CHECK(callContractFunction("balanceOf(address)", ACCOUNT(1)) == encodeArgs(0));
+}
+
+BOOST_AUTO_TEST_CASE(invalid_transfer_2)
+{
+	deployErc20();
+
+	// Separate transfers that together exceed initial balance.
+	int transfer = 1 + TOKENSUPPLY / 2;
+	m_sender = account(0);
+
+	// First transfer should succeed.
+	BOOST_REQUIRE(callContractFunction("transfer(address,uint256)", ACCOUNT(1), u256(transfer)) == SUCCESS);
+	BOOST_REQUIRE(callContractFunction("balanceOf(address)", ACCOUNT(0)) == encodeArgs(TOKENSUPPLY - transfer));
+	BOOST_REQUIRE(callContractFunction("balanceOf(address)", ACCOUNT(1)) == encodeArgs(transfer));
+
+	// Second transfer should fail.
+	BOOST_CHECK(callContractFunction("transfer(address,uint256)", ACCOUNT(1), u256(transfer)) != SUCCESS);
+	BOOST_CHECK(callContractFunction("balanceOf(address)", ACCOUNT(0)) == encodeArgs(TOKENSUPPLY - transfer));
+	BOOST_CHECK(callContractFunction("balanceOf(address)", ACCOUNT(1)) == encodeArgs(transfer));
+}
+
+BOOST_AUTO_TEST_CASE(invalid_transfer_from)
+{
+	deployErc20();
+
+	// TransferFrom without approval.
+	int transfer = 300;
+
+	// Send account(1) some ether for gas.
+	m_sender = account(0);
+	sendEther(account(1), 1000 * ether);
+	BOOST_REQUIRE(balanceAt(account(1)) >= 1000 * ether);
+
+	// Try the transfer; ensure nothing changes.
+	m_sender = account(1);
+	BOOST_CHECK(callContractFunction("transferFrom(address,address,uint256)", ACCOUNT(0), ACCOUNT(2), u256(transfer)) != SUCCESS);
+	BOOST_CHECK(callContractFunction("balanceOf(address)", ACCOUNT(2)) == encodeArgs(0));
+	BOOST_CHECK(callContractFunction("balanceOf(address)", ACCOUNT(0)) == encodeArgs(TOKENSUPPLY));
+	BOOST_CHECK(callContractFunction("allowance(address,address)", ACCOUNT(0), ACCOUNT(1)) == encodeArgs(0));
+}
+
+BOOST_AUTO_TEST_CASE(invalid_reapprove)
+{
+	deployErc20();
+
+	m_sender = account(0);
+
+	// Approve account(1) to transfer up to 1000 tokens from account(0).
+	int allow1 = 1000;
+	BOOST_REQUIRE(callContractFunction("approve(address,uint256)", ACCOUNT(1), u256(allow1)) == SUCCESS);
+	BOOST_REQUIRE(callContractFunction("allowance(address,address)", ACCOUNT(0), ACCOUNT(1)) == encodeArgs(allow1));
+
+	// Now approve account(1) to transfer up to 500 tokens from account(0).
+	// Should fail (we need to reset allowance to 0 first).
+	int allow2 = 500;
+	BOOST_CHECK(callContractFunction("approve(address,uint256)", ACCOUNT(1), u256(allow2)) != SUCCESS);
+	BOOST_CHECK(callContractFunction("allowance(address,address)", ACCOUNT(0), ACCOUNT(1)) == encodeArgs(allow1));
+}
+
+BOOST_AUTO_TEST_CASE(bad_data)
+{
+	deployErc20();
+
+	m_sender = account(0);
+
+	// Correct data: transfer(address _to, 1).
+	sendMessage((bytes)fromHex("a9059cbb") + (bytes)fromHex("000000000000000000000000123456789a123456789a123456789a123456789a") + encodeArgs(1), false, 0);
+	BOOST_CHECK(m_output == SUCCESS);
+
+	// Too little data (address is truncated by one byte).
+	sendMessage((bytes)fromHex("a9059cbb") + (bytes)fromHex("000000000000000000000000123456789a123456789a123456789a12345678") + encodeArgs(1), false, 0);
+	BOOST_CHECK(m_output != SUCCESS);
+
+	// Too much data (address is extended with a zero byte).
+	sendMessage((bytes)fromHex("a9059cbb") + (bytes)fromHex("000000000000000000000000123456789a123456789a123456789a123456789a00") + encodeArgs(1), false, 0);
+	BOOST_CHECK(m_output != SUCCESS);
+
+	// Invalid address (a bit above the 160th is set).
+	sendMessage((bytes)fromHex("a9059cbb") + (bytes)fromHex("000000000000000000000100123456789a123456789a123456789a123456789a") + encodeArgs(1), false, 0);
+	BOOST_CHECK(m_output != SUCCESS);
+}
+
+BOOST_AUTO_TEST_SUITE_END()
+
+}
+}
+} // end namespaces