perf(p/fuzz): optimize int256 generation

contract/p/gnoswap/fuzz/int256_test.gno

@@ -185,3 +185,62 @@ func TestInt256_Int256RangePositiveOnly(t *testing.T) {
 		}
 	})
 }
+
+func TestUint256Range_PreservesSwapBounds(t *testing.T) {
+	const (
+		minPrice = "4295128740"
+		maxPrice = "1461446703485210103287273052203988822378723970341"
+	)
+
+	gen := Uint256Range(minPrice, maxPrice)
+	impl, ok := gen.impl.(*uint256Gen)
+	if !ok {
+		t.Fatalf("unexpected generator implementation: %T", gen.impl)
+	}
+
+	minBefore := impl.min.ToString()
+	maxBefore := impl.max.ToString()
+
+	CheckN(t, 5, func(ft *T) {
+		val := gen.Draw(ft, "priceLimit").(*uint256.Uint)
+
+		if val.Cmp(impl.min) < 0 || val.Cmp(impl.max) > 0 {
+			ft.Fatalf("value %s out of range [%s, %s]", val.ToString(), impl.min.ToString(), impl.max.ToString())
+		}
+		if val == impl.min || val == impl.max {
+			ft.Fatalf("generator returned internal bound pointer")
+		}
+	})
+
+	if impl.min.ToString() != minBefore || impl.max.ToString() != maxBefore {
+		t.Fatalf("generator bounds mutated during draws")
+	}
+}
+
+func TestInt256Range_SingleValueReturnsClone(t *testing.T) {
+	const value = "-12345678901234567890"
+
+	gen := Int256Range(value, value)
+	impl, ok := gen.impl.(*int256Gen)
+	if !ok {
+		t.Fatalf("unexpected generator implementation: %T", gen.impl)
+	}
+
+	minBefore := impl.min.ToString()
+	maxBefore := impl.max.ToString()
+
+	CheckN(t, 3, func(ft *T) {
+		val := gen.Draw(ft, "singleVal").(*int256.Int)
+
+		if val.ToString() != value {
+			ft.Fatalf("value %s differs from expected %s", val.ToString(), value)
+		}
+		if val == impl.min || val == impl.max {
+			ft.Fatalf("generator returned internal bound pointer")
+		}
+	})
+
+	if impl.min.ToString() != minBefore || impl.max.ToString() != maxBefore {
+		t.Fatalf("generator bounds mutated during draws")
+	}
+}

contract/p/gnoswap/fuzzutils/runner.gno

@@ -8,9 +8,10 @@
 	"gno.land/p/nt/ufmt"
 )
 
 func RunFuzzTest(t *testing.T, iterations int, fn func(*fuzz.T, *Result, int), options ...any) {
 	result := NewFuzzResult(fuzz.BASE_SEED)
 	isHandlePanic := true
+	isPrintLog := true
 	index := 0
 
 	if len(options) > 0 {
@@ -20,6 +21,13 @@
 		}
 	}
 
+	if len(options) > 1 {
+		isPrintLogOption, ok := options[1].(bool)
+		if ok {
+			isPrintLog = isPrintLogOption
+		}
+	}
+
 	// Use CheckN instead of CheckWithConfig
 	fuzz.CheckN(t, iterations, func(ft *fuzz.T) {
 		index++
@@ -45,6 +53,14 @@
 			fn(ft, result, index)
 		}
 
+		if isPrintLog {
+			if isError {
+				ufmt.Printf("[LOG-%d] %s (error: %s)\n", index, result.params[index].ToString(), errorMessage)
+			} else {
+				ufmt.Printf("[LOG-%d] %s (valid)\n", index, result.params[index].ToString())
+			}
+		}
+
 		if isError {
 			message := strings.TrimSpace(errorMessage)
 			result.AddErrorMessage(index, message)