[#72] chain/test: Refactor fuzz tests

Make it possible to execute fuzz tests with different backend, such as
go-fuzz which supports coverage collection.

Signed-off-by: Evgenii Stratonikov <e.stratonikov@yadro.com>

pkg/chain/marshal_binary_test.go

@@ -28,31 +28,6 @@ func TestInvalidChainData(t *testing.T) {
 	require.Error(t, ch.UnmarshalBinary([]byte("\x00\x00:aws:iam::namespace:group/so\x82\x82\x82\x82\x82\x82u\x82")))
 }
 
-func FuzzUnmarshal(f *testing.F) {
-	for _, id := range generateTestIDs() {
-		for _, rules := range generateTestRules() {
-			for _, matchType := range generateTestMatchTypes() {
-
-				chain := Chain{
-					ID:        id,
-					Rules:     rules,
-					MatchType: matchType,
-				}
-				data, err := chain.MarshalBinary()
-				require.NoError(f, err)
-				f.Add(data)
-			}
-		}
-	}
-
-	f.Fuzz(func(t *testing.T, data []byte) {
-		var ch Chain
-		require.NotPanics(t, func() {
-			_ = ch.UnmarshalBinary(data)
-		})
-	})
-}
-
 func performMarshalTest(t *testing.T, id ID, r []Rule, mt MatchType) {
 	chain := Chain{
 		ID:        id,

pkg/chain/marshal_fuzz.go

@@ -0,0 +1,13 @@
+//go:build gofuzz
+// +build gofuzz
+
+package chain
+
+func DoFuzzChainUnmarshalBinary(data []byte) int {
+	var ch Chain
+	err := ch.UnmarshalBinary(data)
+	if err != nil {
+		return 0
+	}
+	return 1
+}

pkg/chain/marshal_fuzz_test.go

@@ -0,0 +1,34 @@
+//go:build gofuzz
+// +build gofuzz
+
+package chain
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func FuzzUnmarshal(f *testing.F) {
+	for _, id := range generateTestIDs() {
+		for _, rules := range generateTestRules() {
+			for _, matchType := range generateTestMatchTypes() {
+
+				chain := Chain{
+					ID:        id,
+					Rules:     rules,
+					MatchType: matchType,
+				}
+				data, err := chain.MarshalBinary()
+				require.NoError(f, err)
+				f.Add(data)
+			}
+		}
+	}
+
+	f.Fuzz(func(t *testing.T, data []byte) {
+		require.NotPanics(t, func() {
+			DoFuzzChainUnmarshalBinary(data)
+		})
+	})
+}