feat(checkers): coin checker functions

util/checkers/coin.go

@@ -0,0 +1,20 @@
+package checkers
+
+import (
+	"fmt"
+
+	sdk "github.com/cosmos/cosmos-sdk/types"
+)
+
+// PositiveCoins checks if all coins are valida and amount is positive.
+func PositiveCoins(note string, coins ...sdk.Coin) []error {
+	var errs []error
+	for i := range coins {
+		if err := coins[i].Validate(); err != nil {
+			errs = append(errs, fmt.Errorf("%s coin[%d]: %w", note, i, err))
+		} else if !coins[i].Amount.IsPositive() {
+			errs = append(errs, fmt.Errorf("%s coin[%d] amount must be positive", note, i))
+		}
+	}
+	return errs
+}

util/checkers/coin_test.go

@@ -0,0 +1,30 @@
+package checkers
+
+import (
+	"testing"
+
+	sdk "github.com/cosmos/cosmos-sdk/types"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestCoinPositive(t *testing.T) {
+	assert := assert.New(t)
+
+	c0 := sdk.NewInt64Coin("abc", 0)
+	cNeg := sdk.NewInt64Coin("abc", 0)
+	cPos := sdk.NewInt64Coin("abc", 1)
+
+	assert.Empty(PositiveCoins(""))
+	assert.Empty(PositiveCoins("", cPos))
+	assert.Empty(PositiveCoins("", cPos, cPos))
+
+	assert.Contains(errsToStr(PositiveCoins("", c0)), "coin[0]")
+	assert.Contains(errsToStr(PositiveCoins("", cNeg)), "coin[0]")
+	assert.Contains(errsToStr(PositiveCoins("", cPos, c0)), "coin[1]")
+	assert.Contains(errsToStr(PositiveCoins("", cPos, cNeg)), "coin[1]")
+	assert.NotContains(errsToStr(PositiveCoins("", cPos, cNeg)), "coin[0]")
+
+	assert.Contains(errsToStr(PositiveCoins("", cPos, c0, cNeg)), "coin[1]")
+	assert.Contains(errsToStr(PositiveCoins("", cPos, c0, cNeg)), "coin[2]")
+	assert.NotContains(errsToStr(PositiveCoins("", cPos, c0, cNeg)), "coin[0]")
+}

util/checkers/helper_test.go

@@ -0,0 +1,13 @@
+package checkers
+
+import (
+	"strings"
+)
+
+func errsToStr(errs []error) string {
+	strs := make([]string, len(errs))
+	for i := range errs {
+		strs[i] = errs[i].Error()
+	}
+	return strings.Join(strs, "    ")
+}