From e7ce621ebf06c79fa965497df5bcdd39ae0c713b Mon Sep 17 00:00:00 2001
From: Martin Holst Swende <martin@swende.se>
Date: Sun, 24 Sep 2017 14:26:58 +0200
Subject: [PATCH] tests: add the difficulty-test

---
 tests/difficulty_test.go | 141 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 141 insertions(+)
 create mode 100644 tests/difficulty_test.go

diff --git a/tests/difficulty_test.go b/tests/difficulty_test.go
new file mode 100644
index 0000000000..aa0977277f
--- /dev/null
+++ b/tests/difficulty_test.go
@@ -0,0 +1,141 @@
+package tests
+
+import (
+	"testing"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/common/math"
+	"github.com/ethereum/go-ethereum/consensus/ethash"
+	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/params"
+	"math/big"
+	"strings"
+)
+
+type DifficultyTests map[string]difficultyTest
+
+//go:generate gencodec -type difficultyTest -field-override difficultyTestMarshaling -out gen_difficultytest.go
+
+type difficultyTest struct {
+	ParentTimestamp    *big.Int    `json:"parentTimestamp"`
+	ParentDifficulty   *big.Int    `json:"parentDifficulty"`
+	UncleHash          common.Hash `json:"parentUncles"`
+	CurrentTimestamp   *big.Int    `json:"currentTimestamp"`
+	CurrentBlockNumber uint64      `json:"currentBlockNumber"`
+	CurrentDifficulty  *big.Int    `json:"currentDifficulty"`
+}
+
+type difficultyTestMarshaling struct {
+	ParentTimestamp    *math.HexOrDecimal256
+	ParentDifficulty   *math.HexOrDecimal256
+	CurrentTimestamp   *math.HexOrDecimal256
+	CurrentDifficulty  *math.HexOrDecimal256
+	UncleHash          common.Hash
+	CurrentBlockNumber math.HexOrDecimal64
+}
+
+var (
+	// Values taken from
+	// https://github.com/ethereum/cpp-ethereum/blob/6cb2c852700024daf79e7cb31e4c12ffb7d85537/test/unittests/libethcore/difficulty.cpp#L212
+	// and
+	// https://github.com/ethereum/cpp-ethereum/blob/develop/libethashseal/genesis/test/mainNetworkTest.cpp
+
+	customMainnetConfig = &params.ChainConfig{
+		ChainId:        big.NewInt(1),
+		HomesteadBlock: big.NewInt(0x118c30),
+		DAOForkBlock:   nil,
+		DAOForkSupport: true,
+		EIP150Block:    big.NewInt(0x259518),
+		EIP155Block:    big.NewInt(0x259518),
+		EIP158Block:    big.NewInt(0x28d138),
+		ByzantiumBlock: big.NewInt(0x2dc6c0),
+	}
+
+	homesteadConfig = &params.ChainConfig{
+		ChainId:        big.NewInt(1),
+		HomesteadBlock: big.NewInt(0),
+		DAOForkBlock:   nil,
+		DAOForkSupport: true,
+		EIP150Block:    big.NewInt(math.MaxInt64),
+		EIP155Block:    big.NewInt(math.MaxInt64),
+		EIP158Block:    big.NewInt(math.MaxInt64),
+		ByzantiumBlock: big.NewInt(math.MaxInt64),
+	}
+	frontierConfig = &params.ChainConfig{
+		ChainId:        big.NewInt(1),
+		HomesteadBlock: big.NewInt(math.MaxInt64),
+		DAOForkBlock:   nil,
+		DAOForkSupport: true,
+		EIP150Block:    big.NewInt(math.MaxInt64),
+		EIP155Block:    big.NewInt(math.MaxInt64),
+		EIP158Block:    big.NewInt(math.MaxInt64),
+		ByzantiumBlock: big.NewInt(math.MaxInt64),
+	}
+	byzantiumConfig = &params.ChainConfig{
+		ChainId:        big.NewInt(1),
+		HomesteadBlock: big.NewInt(0),
+		DAOForkBlock:   nil,
+		DAOForkSupport: true,
+		EIP150Block:    big.NewInt(0),
+		EIP155Block:    big.NewInt(0),
+		EIP158Block:    big.NewInt(0),
+		ByzantiumBlock: big.NewInt(0),
+	}
+)
+
+func TestDifficulty(t *testing.T) {
+	t.Parallel()
+
+	dt := new(testMatcher)
+	// Not difficulty-testes
+	dt.skipLoad("hexencodetest.*")
+	dt.skipLoad("crypto.*")
+	dt.skipLoad("blockgenesistest\\.json")
+	dt.skipLoad("genesishashestest\\.json")
+	dt.skipLoad("keyaddrtest\\.json")
+	dt.skipLoad("txtest\\.json")
+
+	// files are 2 years old, strange values
+	dt.skipLoad("difficultyCustomHomestead\\.json")
+	dt.skipLoad("difficultyMorden\\.json")
+	dt.skipLoad("difficultyOlimpic\\.json")
+	// Contains erroneously generated uncle-values : "0x01" -should be hashes
+	dt.skipLoad("difficultyCustomMainNetwork\\.json")
+
+	dt.walk(t, difficultyTestDir, func(t *testing.T, name string, test *difficultyTest) {
+		t.Run(name, func(t *testing.T) {
+			config := params.MainnetChainConfig
+
+			switch {
+			case strings.Contains(name, "Ropsten") || strings.Contains(name, "Morden"):
+				config = params.TestnetChainConfig
+			case strings.Contains(name, "Frontier"):
+				config = frontierConfig
+			case strings.Contains(name, "Homestead"):
+				config = homesteadConfig
+			case strings.Contains(name, "Byzantium"):
+				config = byzantiumConfig
+			case strings.Contains(name, "CustomMainNetwork"):
+				config = customMainnetConfig
+			}
+
+			parentNumber := big.NewInt(int64(test.CurrentBlockNumber - 1))
+			parent := &types.Header{
+				Difficulty: test.ParentDifficulty,
+				Time:       test.ParentTimestamp,
+				Number:     parentNumber,
+				UncleHash:  test.UncleHash,
+			}
+
+			actual := ethash.CalcDifficulty(config, test.CurrentTimestamp.Uint64(), parent)
+			exp := test.CurrentDifficulty
+
+			if actual.Cmp(exp) != 0 {
+
+				t.Errorf("parent[time %v diff %v #uncles:%v] child[time %v number %v] diff %v != expected %v",
+					test.ParentTimestamp, test.ParentDifficulty, test.UncleHash,
+					test.CurrentTimestamp, test.CurrentBlockNumber, actual, exp)
+			}
+		})
+	})
+}