Merge PR #3818: Introduce sdk.NewCoins

types/coin.go

@@ -130,6 +130,28 @@ func (coin Coin) IsNegative() bool {
 // Coins is a set of Coin, one per currency
 type Coins []Coin
 
+// NewCoins constructs a new coin set.
+func NewCoins(coins ...Coin) Coins {
+	// remove zeroes
+	newCoins := removeZeroCoins(Coins(coins))
+	if len(newCoins) == 0 {
+		return Coins{}
+	}
+
+	newCoins.Sort()
+
+	// detect duplicate Denoms
+	if dupIndex := findDup(newCoins); dupIndex != -1 {
+		panic(fmt.Errorf("find duplicate denom: %s", newCoins[dupIndex]))
+	}
+
+	if !newCoins.IsValid() {
+		panic(fmt.Errorf("invalid coin set: %s", newCoins))
+	}
+
+	return newCoins
+}
+
 func (coins Coins) String() string {
 	if len(coins) == 0 {
 		return ""
@@ -552,3 +574,19 @@ func ParseCoins(coinsStr string) (coins Coins, err error) {
 
 	return coins, nil
 }
+
+// findDup works on the assumption that coins is sorted
+func findDup(coins Coins) int {
+	if len(coins) <= 1 {
+		return -1
+	}
+
+	prevDenom := coins[0]
+	for i := 1; i < len(coins); i++ {
+		if coins[i] == prevDenom {
+			return i
+		}
+	}
+
+	return -1
+}

types/coin_test.go

@@ -519,3 +519,31 @@ func TestCoinsIsAnyGTE(t *testing.T) {
 	assert.True(t, Coins{{testDenom1, one}, {testDenom2, one}}.IsAnyGTE(Coins{{testDenom1, one}, {testDenom2, two}}))
 	assert.True(t, Coins{{"xxx", one}, {"yyy", one}}.IsAnyGTE(Coins{{testDenom2, one}, {"ccc", one}, {"yyy", one}, {"zzz", one}}))
 }
+
+func TestNewCoins(t *testing.T) {
+	tenatom := NewInt64Coin("atom", 10)
+	tenbtc := NewInt64Coin("btc", 10)
+	zeroeth := NewInt64Coin("eth", 0)
+	tests := []struct {
+		name      string
+		coins     Coins
+		want      Coins
+		wantPanic bool
+	}{
+		{"empty args", []Coin{}, Coins{}, false},
+		{"one coin", []Coin{tenatom}, Coins{tenatom}, false},
+		{"sort after create", []Coin{tenbtc, tenatom}, Coins{tenatom, tenbtc}, false},
+		{"sort and remove zeroes", []Coin{zeroeth, tenbtc, tenatom}, Coins{tenatom, tenbtc}, false},
+		{"panic on dups", []Coin{tenatom, tenatom}, Coins{}, true},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if tt.wantPanic {
+				require.Panics(t, func() { NewCoins(tt.coins...) })
+				return
+			}
+			got := NewCoins(tt.coins...)
+			require.True(t, got.IsEqual(tt.want))
+		})
+	}
+}