test: add Drop to fuzz test, add drop test cases

Makefile

@@ -16,10 +16,12 @@ test-unit: ## Run unit tests with coverage
 test-mutation: ## Run mutation tests with gremlins
 	gremlins unleash
 
+FUZZ_TIME ?= 30
+
 test-fuzz: ## Run all fuzz tests for 30s each
 	@for func in $$(grep -r --include='*_test.go' -oh 'func Fuzz\w*' . | sed 's/func //'); do \
 		echo "Fuzzing $$func..."; \
-		go test ./... -fuzz="^$$func$$" -fuzztime=30s; \
+		go test ./... -fuzz="^$$func$$" -fuzztime=$(FUZZ_TIME)s; \
 	done
 
 test: test-unit test-mutation test-fuzz ## Run all tests

cuckoo_fuzz_test.go

@@ -3,6 +3,7 @@ package cuckoo_test
 import (
 	"bytes"
 	"encoding/binary"
+	"maps"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -23,27 +24,45 @@ func FuzzInsertLookup(f *testing.F) {
 	f.Fuzz(func(t *testing.T, data []byte, seedA, seedB uint32) {
 		assert := assert.New(t)
 
-		table := cuckoo.NewCustomTable[uint32, uint32](
+		actual := cuckoo.NewCustomTable[uint32, uint32](
 			offsetHash(seedA),
 			offsetHash(seedB),
 			func(a, b uint32) bool { return a == b },
 		)
 
+		expected := map[uint32]uint32{}
+
 		if seedA == seedB {
 			return
 		}
 
 		r := bytes.NewReader(data)
 		var key, value uint32
+		var drop bool
 		for binary.Read(r, binary.LittleEndian, &key) == nil &&
 			binary.Read(r, binary.LittleEndian, &value) == nil {
 
-			err := table.Put(key, value)
+			if drop {
+				err := actual.Drop(key)
 				assert.NoError(err)
 
-			found, err := table.Get(key)
+				delete(expected, key)
+
+				_, err = actual.Get(key)
+				assert.Error(err)
+			} else {
+				err := actual.Put(key, value)
+				assert.NoError(err)
+
+				expected[key] = value
+
+				found, err := actual.Get(key)
 				assert.NoError(err)
 				assert.Equal(value, found)
 			}
+			assert.Equal(expected, maps.Collect(actual.Entries()))
+
+			drop = !drop
+		}
 	})
 }

cuckoo_test.go

@@ -129,7 +129,7 @@ func TestRemove(t *testing.T) {
 	assert.True(table.Has(0))
 }
 
-func TestDropItem(t *testing.T) {
+func TestDropExistingItem(t *testing.T) {
 	assert := assert.New(t)
 	key, value := 0, true
 	table := cuckoo.NewTable[int, bool]()
@@ -141,3 +141,15 @@ func TestDropItem(t *testing.T) {
 	assert.Equal(0, table.Size())
 	assert.False(table.Has(key))
 }
+
+func TestDropNoItem(t *testing.T) {
+	assert := assert.New(t)
+	key := 0
+	table := cuckoo.NewTable[int, bool]()
+
+	err := table.Drop(key)
+
+	assert.NoError(err)
+	assert.Equal(0, table.Size())
+	assert.False(table.Has(key))
+}

testdata/fuzz/FuzzInsertLookup/7753b9a0c9a15ea7

@@ -0,0 +1,4 @@
+go test fuzz v1
+[]byte("00000000000000000000000000000000000000000000000000000000000000000000000000000000")
+uint32(51)
+uint32(38)