From f5e1dc52b3453b76c726c9e7438f25d8da4aef01 Mon Sep 17 00:00:00 2001
From: hickford <hickford@google.com>
Date: Thu, 21 Jul 2022 12:22:54 +0100
Subject: [PATCH] Fuzz ConsistencyProof function against reference
 implementation

---
 .clusterfuzzlite/build.sh  |  1 +
 testonly/tree_fuzz_test.go | 29 +++++++++++++++++++++++++++++
 2 files changed, 30 insertions(+)

diff --git a/.clusterfuzzlite/build.sh b/.clusterfuzzlite/build.sh
index 8c7bc09..adbe663 100644
--- a/.clusterfuzzlite/build.sh
+++ b/.clusterfuzzlite/build.sh
@@ -15,3 +15,4 @@ compile_native_go_fuzzer github.com/transparency-dev/merkle/testonly FuzzConsist
 compile_native_go_fuzzer github.com/transparency-dev/merkle/testonly FuzzInclusionProofAndVerify FuzzInclusionProofAndVerify
 compile_native_go_fuzzer github.com/transparency-dev/merkle/testonly FuzzHashAtAgainstReferenceImplementation FuzzHashAtAgainstReferenceImplementation
 compile_native_go_fuzzer github.com/transparency-dev/merkle/testonly FuzzInclusionProofAgainstReferenceImplementation FuzzInclusionProofAgainstReferenceImplementation
+compile_native_go_fuzzer github.com/transparency-dev/merkle/testonly FuzzConsistencyProofAgainstReferenceImplementation FuzzConsistencyProofAgainstReferenceImplementation
diff --git a/testonly/tree_fuzz_test.go b/testonly/tree_fuzz_test.go
index f884017..2dd1b29 100644
--- a/testonly/tree_fuzz_test.go
+++ b/testonly/tree_fuzz_test.go
@@ -122,3 +122,32 @@ func FuzzInclusionProofAgainstReferenceImplementation(f *testing.F) {
 		}
 	})
 }
+
+func FuzzConsistencyProofAgainstReferenceImplementation(f *testing.F) {
+	for size := 0; size <= 8; size++ {
+		for end := 0; end <= size; end++ {
+			for begin := 0; begin <= end; begin++ {
+				f.Add(uint64(size), uint64(begin), uint64(end))
+			}
+		}
+	}
+	f.Fuzz(func(t *testing.T, size, begin, end uint64) {
+		if size >= math.MaxUint16 {
+			return
+		}
+		t.Logf("size=%d, begin=%d, end=%d", size, begin, end)
+		if begin > end || end > size {
+			return
+		}
+		entries := genEntries(size)
+		tree := newTree(entries)
+		got, err := tree.ConsistencyProof(begin, end)
+		if err != nil {
+			t.Errorf("ConsistencyProof: %v", err)
+		}
+		want := refConsistencyProof(entries[:end], end, begin, tree.hasher, true)
+		if diff := cmp.Diff(got, want, cmpopts.EquateEmpty()); diff != "" {
+			t.Errorf("ConsistencyProof: diff (-got +want)\n%s", diff)
+		}
+	})
+}