DO NOT USE. Attempt to convert Eth to Wei. Not 100% accurate.

ethutils.go

// Attempt to convert Eth to Wei
package utils

import (
	"log"
	"math"
	"math/big"
)

// EthToWei converts eth to wei
// Doesn't work. Can't get 100% accuracy
func EthToWei(ethAmount *big.Float) *big.Int {
	log.Printf("Input eth: %18.18f\n", ethAmount)
	factor := big.NewFloat(math.Pow10(18))
	log.Printf("factor: %f", factor)
	wei := ethAmount.Mul(ethAmount, factor)
	log.Printf("resulting wei (big.Float64): %18.18f", wei)
	out, accuracy := wei.Int64()
	if accuracy != big.Exact {
		log.Fatalf("could not convert eth %d to wei", ethAmount)
		return nil
	}
	log.Printf("out: %d, accuracy: %v", out, accuracy)
	return big.NewInt(out)
}

// Want: 3141592653589793238
// But gets: 3141592653589793280

ethutils_test.go

package utils

import (
	"math/big"
	"reflect"
	"testing"
)

func TestEthToWei(t *testing.T) {
	type args struct {
		ethAmount *big.Float
	}
	tests := []struct {
		name string
		args args
		want *big.Int
	}{
		{
			name: "Convert 1 eth to 10^18 wei",
			args: args{ethAmount: big.NewFloat(3.141592653589793238)},
			want: big.NewInt(3141592653589793238),
		},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			if got := EthToWei(tt.args.ethAmount); !reflect.DeepEqual(got, tt.want) {
				t.Errorf("EthToWei() = %v, want %v", got, tt.want)
			}
		})
	}
}