Add mock EthClient for testing

eth/client_test.go

@@ -0,0 +1,14 @@
+package eth
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestClientInterface(t *testing.T) {
+	var c ClientInterface
+	client := NewClient(nil, nil, nil, nil)
+	c = client
+	require.NotNil(t, c)
+}

eth/interface.go

@@ -0,0 +1,18 @@
+package eth
+
+import (
+	"context"
+	"math/big"
+
+	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/hermeznetwork/hermez-node/common"
+)
+
+// ClientInterface is the eth Client interface used by hermez-node modules to
+// interact with Ethereum Blockchain and smart contracts.
+type ClientInterface interface {
+	CurrentBlock() (*big.Int, error)
+	HeaderByNumber(context.Context, *big.Int) (*types.Header, error)
+	BlockByNumber(context.Context, *big.Int) (*common.Block, error)
+	ForgeCall(*common.CallDataForge) ([]byte, error)
+}