swap: correction of swapout in CheckPremiumAmount

Corrected where to get premium limit at swapout in
CheckPremiumAmount and OnSwapOutRequestReceived.
Also, unit tests for CheckPremiumAmount have been added.

swap/actions.go

@@ -212,7 +212,7 @@ func (v *CheckPremiumAmount) Execute(services *SwapServices, swap *SwapData) Eve
 	} else if swap.SwapOutAgreement != nil {
 		if swap.SwapOutAgreement.Premium > swap.SwapOutRequest.PremiumLimit {
 			return swap.HandleError(fmt.Errorf("premium amt too high: %d, limit : %d",
-				swap.SwapOutAgreement.Premium, swap.SwapInRequest.PremiumLimit))
+				swap.SwapOutAgreement.Premium, swap.SwapOutRequest.PremiumLimit))
 		}
 		return v.next.Execute(services, swap)
 	}

swap/actions_test.go

@@ -0,0 +1,73 @@
+package swap
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestCheckPremiumAmount_Execute(t *testing.T) {
+	t.Parallel()
+	next := &NoOpAction{}
+	v := CheckPremiumAmount{
+		next: next,
+	}
+	tests := map[string]struct {
+		swap *SwapData
+		want EventType
+	}{
+		"swap in premium amount is within limit": {
+			swap: &SwapData{
+				SwapInAgreement: &SwapInAgreementMessage{
+					Premium: 100,
+				},
+				SwapInRequest: &SwapInRequestMessage{
+					PremiumLimit: 200,
+				},
+			},
+			want: NoOp,
+		},
+		"swap in premium amount exceeds limit": {
+			swap: &SwapData{
+				SwapInAgreement: &SwapInAgreementMessage{
+					Premium: 300,
+				},
+				SwapInRequest: &SwapInRequestMessage{
+					PremiumLimit: 200,
+				},
+			},
+			want: Event_ActionFailed,
+		},
+		"swap out premium amount is within limit": {
+			swap: &SwapData{
+				SwapOutAgreement: &SwapOutAgreementMessage{
+					Premium: 100,
+				},
+				SwapOutRequest: &SwapOutRequestMessage{
+					PremiumLimit: 200,
+				},
+			},
+			want: NoOp,
+		},
+		"swap out premium amount exceeds limit": {
+			swap: &SwapData{
+				SwapOutAgreement: &SwapOutAgreementMessage{
+					Premium: 300,
+				},
+				SwapOutRequest: &SwapOutRequestMessage{
+					PremiumLimit: 200,
+				},
+			},
+			want: Event_ActionFailed,
+		},
+	}
+
+	for name, tt := range tests {
+		tt := tt
+		t.Run(name, func(t *testing.T) {
+			t.Parallel()
+			got := v.Execute(nil, tt.swap)
+			assert.Equal(t, tt.want, got, "Event type should match")
+		})
+	}
+}

swap/service.go

@@ -609,7 +609,7 @@ func (s *SwapService) OnSwapInRequestReceived(swapId *SwapId, peerId string, mes
 
 // OnSwapInRequestReceived creates a new swap-out process and sends the event to the swap statemachine
 func (s *SwapService) OnSwapOutRequestReceived(swapId *SwapId, peerId string, message *SwapOutRequestMessage) error {
-	premium := ComputePremium(message.Amount, s.swapServices.policy.GetSwapInPremiumRatePPM())
+	premium := ComputePremium(message.Amount, s.swapServices.policy.GetSwapOutPremiumRatePPM())
 	if premium > message.PremiumLimit {
 		err := fmt.Errorf("unacceptable premium: %d, limit: %d", premium, message.PremiumLimit)
 		msg := fmt.Sprintf("from the %s peer: %s", s.swapServices.lightning.Implementation(), err.Error())