Fuzz ConsistencyProof function against reference implementation

testonly/tree_fuzz_test.go

@@ -0,0 +1,36 @@
+//go:build go1.18
+
+package testonly
+
+import (
+	"testing"
+
+	"github.com/google/go-cmp/cmp"
+	"github.com/google/go-cmp/cmp/cmpopts"
+)
+
+func FuzzConsistencyProofAgainstReferenceImplementation(f *testing.F) {
+	for size := 0; size <= 8; size++ {
+		for size2 := 0; size2 <= size; size2++ {
+			for size1 := 0; size1 <= size2; size1++ {
+				f.Add(uint64(size), uint64(size1), uint64(size2))
+			}
+		}
+	}
+	f.Fuzz(func(t *testing.T, size, size1, size2 uint64) {
+		t.Logf("size=%d, size1=%d, size2=%d", size, size1, size2)
+		if size1 > size2 || size2 > size {
+			return
+		}
+		entries := genEntries(size)
+		tree := newTree(entries)
+		got, err := tree.ConsistencyProof(size1, size2)
+		if err != nil {
+			t.Fatalf("ConsistencyProof: %v", err)
+		}
+		want := refConsistencyProof(entries[:size2], size2, size1, tree.hasher, true)
+		if diff := cmp.Diff(got, want, cmpopts.EquateEmpty()); diff != "" {
+			t.Errorf("ConsistencyProof: diff (-got +want)\n%s", diff)
+		}
+	})
+}