test: x/tx/signing/textual: fuzz CoinsValueRenderer (#16521)

Co-authored-by: Marko <marbar3778@yahoo.com>
Co-authored-by: atheeshp <59333759+atheeshp@users.noreply.github.com>

x/tx/go.mod

@@ -22,6 +22,7 @@ require (
 	github.com/cosmos/gogoproto v1.4.10 // indirect
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/golang/protobuf v1.5.3 // indirect
+	github.com/google/gofuzz v1.2.0 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
 	golang.org/x/exp v0.0.0-20230522175609-2e198f4a06a1 // indirect
 	golang.org/x/net v0.11.0 // indirect

x/tx/go.sum

@@ -20,8 +20,9 @@ github.com/golang/protobuf v1.5.3/go.mod h1:XVQd3VNwM+JqD3oG2Ue2ip4fOMUkwXdXDdiu
 github.com/google/go-cmp v0.5.5/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
 github.com/google/go-cmp v0.5.9 h1:O2Tfq5qg4qc4AmwVlvv0oLiVAGB7enBSJ2x2DqQFi38=
 github.com/google/go-cmp v0.5.9/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
-github.com/google/gofuzz v0.0.0-20170612174753-24818f796faf h1:+RRA9JqSOZFfKrOeqr2z77+8R2RKyh8PG66dcu1V0ck=
 github.com/google/gofuzz v0.0.0-20170612174753-24818f796faf/go.mod h1:HP5RmnzzSNb993RKQDq4+1A4ia9nllfqcQFTQJedwGI=
+github.com/google/gofuzz v1.2.0 h1:xRy4A+RhZaiKjJ1bPfwQ8sedCA+YS2YcCHW6ec7JMi0=
+github.com/google/gofuzz v1.2.0/go.mod h1:dBl0BpW6vV/+mYPU4Po3pmUjxk6FQPldtuIdl/M65Eg=
 github.com/iancoleman/strcase v0.2.0 h1:05I4QRnGpI0m37iZQRuskXh+w77mr6Z41lwQzuHLwW0=
 github.com/iancoleman/strcase v0.2.0/go.mod h1:iwCmte+B7n89clKwxIoIXy/HfoL7AsD47ZCWhYzw7ho=
 github.com/kr/pretty v0.3.1 h1:flRD4NNwYAUpkphVc1HcthR4KEIFJ65n8Mw5qdRn3LE=

x/tx/signing/textual/coins_test.go

@@ -71,7 +71,7 @@ func checkCoinsEqual(t *testing.T, l1, l2 protoreflect.List) {
 
 	for i := 0; i < l1.Len(); i++ {
 		coin, ok := l1.Get(i).Message().Interface().(*basev1beta1.Coin)
-		require.True(t, ok)
+		require.True(t, ok, "not a *basev1beta1.Coin: %#v", l1.Get(i).Message().Interface())
 		coinsMap[coin.Denom] = coin
 	}
 
@@ -90,7 +90,7 @@ func checkCoinEqual(t *testing.T, coin, coin1 *basev1beta1.Coin) {
 	require.True(t, ok)
 	v1, ok := math.NewIntFromString(coin1.Amount)
 	require.True(t, ok)
-	require.True(t, v.Equal(v1))
+	require.True(t, v.Equal(v1), "Mismatch\n\tv:  %+v\n\tv1: %+v", v, v1)
 }
 
 // coinsJSONTest is the type of test cases in the testdata file.

x/tx/signing/textual/fuzz_test.go

@@ -5,6 +5,7 @@ import (
 	"context"
 	"encoding/json"
 	"os"
+	"regexp"
 	"testing"
 
 	"github.com/google/go-cmp/cmp"
@@ -12,6 +13,7 @@ import (
 	"google.golang.org/protobuf/testing/protocmp"
 	tspb "google.golang.org/protobuf/types/known/timestamppb"
 
+	basev1beta1 "cosmossdk.io/api/cosmos/base/v1beta1"
 	"cosmossdk.io/x/tx/internal/testpb"
 	"cosmossdk.io/x/tx/signing/textual"
 )
@@ -211,3 +213,87 @@ func FuzzMessageValueRendererParse(f *testing.F) {
 		}
 	})
 }
+
+// Copied from types/coin.go but pasted in here so as to avoid any imports
+// of that package as has been mandated by team decisions.
+var (
+	reCoinDenom  = regexp.MustCompile(`[a-zA-Z][a-zA-Z0-9/:._-]{2,127}`)
+	reCoinAmount = regexp.MustCompile(`[[:digit:]]+(?:\.[[:digit:]]+)?|\.[[:digit:]]+`)
+)
+
+func FuzzCoinsJSONTestcases(f *testing.F) {
+	// Generate some seeds.
+	seed, err := os.ReadFile("./internal/testdata/coins.json")
+	if err != nil {
+		f.Fatal(err)
+	}
+	f.Add(seed)
+
+	txt, err := textual.NewSignModeHandler(textual.SignModeOptions{CoinMetadataQuerier: mockCoinMetadataQuerier})
+	if err != nil {
+		f.Fatal(err)
+	}
+	rend, err := txt.GetFieldValueRenderer(fieldDescriptorFromName("COINS"))
+	if err != nil {
+		f.Fatal(err)
+	}
+	vrr := rend.(textual.RepeatedValueRenderer)
+
+	f.Fuzz(func(t *testing.T, input []byte) {
+		var testCases []coinsJSONTest
+		if err := json.Unmarshal(input, &testCases); err != nil {
+			return
+		}
+
+		for _, tc := range testCases {
+			if tc.Proto == nil {
+				continue
+			}
+
+			// Create a context.Context containing all coins metadata, to simulate
+			// that they are in state.
+			ctx := context.Background()
+			for _, v := range tc.Metadata {
+				ctx = addMetadataToContext(ctx, v)
+			}
+
+			listValue := NewGenericList(tc.Proto)
+			screens, err := vrr.FormatRepeated(ctx, protoreflect.ValueOf(listValue))
+			if err != nil {
+				cpt := tc.Proto[0]
+				likeEmpty := err.Error() == "cannot format empty string" || err.Error() == "decimal string cannot be empty"
+				if likeEmpty && (!reCoinDenom.MatchString(cpt.Denom) || cpt.Amount == "") {
+					return
+				}
+				if !reCoinDenom.MatchString(cpt.Denom) {
+					return
+				}
+				if !reCoinAmount.MatchString(cpt.Amount) {
+					return
+				}
+				t.Fatalf("%v\n%q\n%#v => %t", err, tc.Text, cpt, cpt.Amount == "")
+			}
+
+			if g, w := len(screens), 1; g != w {
+				t.Fatalf("Screens mismatch: got=%d want=%d", g, w)
+			}
+
+			wantContent := tc.Text
+			if wantContent == "" {
+				wantContent = "zero"
+			}
+			if false {
+				if g, w := screens[0].Content, wantContent; g != w {
+					t.Fatalf("Content mismatch:\n\tGot:  %s\n\tWant: %s", g, w)
+				}
+			}
+
+			// Round trip.
+			parsedValue := NewGenericList([]*basev1beta1.Coin{})
+			if err := vrr.ParseRepeated(ctx, screens, parsedValue); err != nil {
+				return
+			}
+			checkCoinsEqual(t, listValue, parsedValue)
+		}
+	})
+}

x/tx/signing/textual/testdata/fuzz/FuzzCoinsJSONTestcases/4d81af7cc74558bf

@@ -0,0 +1,2 @@
+go test fuzz v1
+[]byte("[{\"proto\":[{\"Amount\":\"0\"},{\"Amount\":\"1\"}]}]")