fix: test smallest float divided by zero

Signed-off-by: Antonio Navarro Perez <antnavper@gmail.com>

gnovm/pkg/gnolang/values_conversions.go

@@ -1240,7 +1240,11 @@ func ConvertUntypedBigdecTo(dst *TypedValue, bv BigdecValue, t Type) {
 	case Float32Kind:
 		dst.T = t
 		dst.V = nil
-		f64, _ := bd.Float64()
+		f64, err := bd.Float64()
+		if err != nil {
+			panic(fmt.Errorf("cannot convert untyped bigdec to float64: %w", err))
+		}
+
 		bf := big.NewFloat(f64)
 		f32, acc := bf.Float32()
 		if f32 == 0 && (acc == big.Below || acc == big.Above) {
@@ -1253,7 +1257,10 @@ func ConvertUntypedBigdecTo(dst *TypedValue, bv BigdecValue, t Type) {
 	case Float64Kind:
 		dst.T = t
 		dst.V = nil
-		f64, _ := bd.Float64()
+		f64, err := bd.Float64()
+		if err != nil {
+			panic(fmt.Errorf("cannot convert untyped bigdec to float64: %w", err))
+		}
 		if f64 == 0 && !bd.IsZero() {
 			panic("cannot convert untyped bigdec to float64 -- too close to zero")
 		} else if math.IsInf(f64, 0) {

gnovm/pkg/gnolang/values_conversions_test.go

@@ -0,0 +1,25 @@
+package gnolang
+
+import (
+	"math"
+	"testing"
+
+	"github.com/cockroachdb/apd"
+	"github.com/stretchr/testify/require"
+)
+
+func TestConvertUntypedBigdecToFloat(t *testing.T) {
+	dst := &TypedValue{}
+
+	dec, err := apd.New(-math.MaxInt64, -4).SetFloat64(math.SmallestNonzeroFloat64 / 2)
+	require.NoError(t, err)
+	bd := BigdecValue{
+		V: dec,
+	}
+
+	typ := Float64Type
+
+	ConvertUntypedBigdecTo(dst, bd, typ)
+
+	require.Equal(t, float64(0), dst.GetFloat64())
+}

gnovm/tests/machine_test.go

@@ -23,6 +23,11 @@ func TestMachineTestMemPackage(t *testing.T) {
 			path:          "testdata/TestMemPackage/success",
 			shouldSucceed: true,
 		},
+		{
+			name:          "TestSmallestFloat",
+			path:          "testdata/TestMemPackage/success",
+			shouldSucceed: true,
+		},
 		{
 			name:          "TestFail",
 			path:          "testdata/TestMemPackage/fail",

gnovm/tests/testdata/TestMemPackage/success/float_test.gno

@@ -0,0 +1,10 @@
+package test
+
+import "testing"
+
+func TestSmallestFloat(t *testing.T) {
+    SmallestNonzeroFloat64 := 0x1p-1022 * 0x1p-52            // 4.9406564584124654417656879286822137236505980e-324
+	DividedByTwo           := SmallestNonzeroFloat64 / 2
+
+    println(DividedByTwo)
+}