lambda/event: fix TargetIDSet.IsEmpty and add regression test

Signed-off-by: AleksaMCode <aleksamcode@gmail.com>

internal/config/lambda/event/targetidset.go

@@ -24,7 +24,7 @@ type TargetIDSet map[TargetID]struct{}
 
 // IsEmpty returns true if the set is empty.
 func (set TargetIDSet) IsEmpty() bool {
-	return len(set) != 0
+	return len(set) == 0
 }
 
 // Clone - returns copy of this set.

internal/config/lambda/event/targetidset_test.go

@@ -22,6 +22,22 @@ import (
 	"testing"
 )
 
+func TestTargetIDSetIsEmpty(t *testing.T) {
+	testCases := []struct {
+		set      TargetIDSet
+		expected bool
+	}{
+		{NewTargetIDSet(), true},
+		{NewTargetIDSet(TargetID{"1", "webhook"}), false},
+	}
+
+	for i, testCase := range testCases {
+		if got := testCase.set.IsEmpty(); got != testCase.expected {
+			t.Fatalf("test %v: expected: %v, got: %v", i+1, testCase.expected, got)
+		}
+	}
+}
+
 func TestTargetIDSetClone(t *testing.T) {
 	testCases := []struct {
 		set           TargetIDSet