Add tests for pkg/geth/blockchain

- inject dependencies instead of initializing them in the constructor

pkg/fakes/mock_blockchain.go

@@ -0,0 +1,97 @@
+package fakes
+
+import (
+	"math/big"
+
+	"github.com/vulcanize/vulcanizedb/pkg/core"
+)
+
+type MockBlockChain struct {
+	ContractReturnValue []byte
+	WasToldToStop       bool
+	blocks              map[int64]core.Block
+	blocksChannel       chan core.Block
+	contractAttributes  map[string]map[string]string
+	err                 error
+	headers             map[int64]core.Header
+	logs                map[string][]core.Log
+	node                core.Node
+}
+
+func (blockChain *MockBlockChain) GetHeaderByNumber(blockNumber int64) (core.Header, error) {
+	return blockChain.headers[blockNumber], nil
+}
+
+func (blockChain *MockBlockChain) FetchContractData(abiJSON string, address string, method string, methodArg interface{}, result interface{}, blockNumber int64) error {
+	panic("implement me")
+}
+
+func (blockChain *MockBlockChain) CallContract(contractHash string, input []byte, blockNumber *big.Int) ([]byte, error) {
+	return blockChain.ContractReturnValue, nil
+}
+
+func (blockChain *MockBlockChain) LastBlock() *big.Int {
+	var max int64
+	for blockNumber := range blockChain.blocks {
+		if blockNumber > max {
+			max = blockNumber
+		}
+	}
+	return big.NewInt(max)
+}
+
+func (blockChain *MockBlockChain) GetLogs(contract core.Contract, startingBlock *big.Int, endingBlock *big.Int) ([]core.Log, error) {
+	return blockChain.logs[contract.Hash], nil
+}
+
+func (blockChain *MockBlockChain) Node() core.Node {
+	return blockChain.node
+}
+
+func NewMockBlockChain(err error) *MockBlockChain {
+	return &MockBlockChain{
+		blocks:             make(map[int64]core.Block),
+		logs:               make(map[string][]core.Log),
+		contractAttributes: make(map[string]map[string]string),
+		node:               core.Node{GenesisBlock: "GENESIS", NetworkID: 1, ID: "x123", ClientName: "Geth"},
+		err:                err,
+	}
+}
+
+func NewMockBlockChainWithBlocks(blocks []core.Block) *MockBlockChain {
+	blockNumberToBlocks := make(map[int64]core.Block)
+	for _, block := range blocks {
+		blockNumberToBlocks[block.Number] = block
+	}
+	return &MockBlockChain{
+		blocks: blockNumberToBlocks,
+	}
+}
+
+func NewMockBlockChainWithHeaders(headers []core.Header) *MockBlockChain {
+	// need to create blocks and headers so that LastBlock() will work in the mock
+	// no reason to implement LastBlock() separately for headers since it checks
+	// the last header in the Node's DB already
+	memoryBlocks := make(map[int64]core.Block)
+	memoryHeaders := make(map[int64]core.Header)
+	for _, header := range headers {
+		memoryBlocks[header.BlockNumber] = core.Block{Number: header.BlockNumber}
+		memoryHeaders[header.BlockNumber] = header
+	}
+	return &MockBlockChain{
+		blocks:  memoryBlocks,
+		headers: memoryHeaders,
+	}
+}
+
+func (blockChain *MockBlockChain) GetBlockByNumber(blockNumber int64) (core.Block, error) {
+	if blockChain.err != nil {
+		return core.Block{}, blockChain.err
+	}
+	return blockChain.blocks[blockNumber], nil
+}
+
+func (blockChain *MockBlockChain) AddBlock(block core.Block) {
+	blockChain.blocks[block.Number] = block
+	blockChain.blocksChannel <- block
+}