diff --git a/append_handler_test.go b/append_handler_test.go
index ebf868b..f49ff60 100644
--- a/append_handler_test.go
+++ b/append_handler_test.go
@@ -125,10 +125,10 @@ func TestAppendHandler_CaseInsensitiveKeepIfBuiltinConflict(t *testing.T) {
 	t.Parallel()
 
 	tester := &testHandler{}
-	h := NewAppendHandler(tester, &AppendHandlerOptions{
+	h := NewAppendMiddleware(&AppendHandlerOptions{
 		KeyCompare:                CaseInsensitiveCmp,
 		ResolveBuiltinKeyConflict: KeepIfBuiltinKeyConflict,
-	})
+	})(tester)
 
 	log := slog.New(h)
 	log.Info("case insenstive, keep builtin conflict", "arg1", "val1", "ARG1", "val2", slog.MessageKey, "builtin-conflict")
diff --git a/ignore_handler_test.go b/ignore_handler_test.go
index cfaac4d..7482374 100644
--- a/ignore_handler_test.go
+++ b/ignore_handler_test.go
@@ -1,6 +1,7 @@
 package slogdedup
 
 import (
+	"log/slog"
 	"strings"
 	"testing"
 )
@@ -51,3 +52,37 @@ func TestIgnoreHandler(t *testing.T) {
 
 	checkRecordForDuplicates(t, tester.Record)
 }
+
+func TestIgnoreHandler_ResolveBuiltinKeyConflict(t *testing.T) {
+	t.Parallel()
+
+	tester := &testHandler{}
+	h := NewIgnoreMiddleware(&IgnoreHandlerOptions{
+		ResolveBuiltinKeyConflict: func(k string) (string, bool) {
+			if k == "time" {
+				return "", false
+			} else {
+				return "arg-" + k, true
+			}
+		},
+	})(tester)
+
+	slog.New(h).Info("main message", "time", "hello", "foo", "bar")
+
+	jBytes, err := tester.MarshalJSON()
+	if err != nil {
+		t.Errorf("Unable to marshal json: %v", err)
+	}
+	jStr := strings.TrimSpace(string(jBytes))
+
+	expected := `{"time":"2023-09-29T13:00:59Z","level":"INFO","msg":"main message","arg-foo":"bar"}`
+	if jStr != expected {
+		t.Errorf("Expected:\n%s\nGot:\n%s", expected, jStr)
+	}
+
+	// Uncomment to see the results
+	// t.Error(jStr)
+	// t.Error(tester.String())
+
+	checkRecordForDuplicates(t, tester.Record)
+}
diff --git a/increment_handler_test.go b/increment_handler_test.go
index df215c1..866836e 100644
--- a/increment_handler_test.go
+++ b/increment_handler_test.go
@@ -1,6 +1,8 @@
 package slogdedup
 
 import (
+	"log/slog"
+	"strconv"
 	"strings"
 	"testing"
 )
@@ -90,3 +92,39 @@ func TestIncrementHandler(t *testing.T) {
 
 	checkRecordForDuplicates(t, tester.Record)
 }
+
+func TestIncrementHandler_DoesKeyConflict_IncrementKeyName(t *testing.T) {
+	t.Parallel()
+
+	tester := &testHandler{}
+	h := NewIncrementMiddleware(&IncrementHandlerOptions{
+		DoesBuiltinKeyConflict: func(key string) bool {
+			if key == "foo" {
+				return true
+			}
+			return false
+		},
+		IncrementKeyName: func(key string, index int) string {
+			return key + "@" + strconv.Itoa(index)
+		},
+	})(tester)
+
+	slog.New(h).Info("main message", "foo", "bar")
+
+	jBytes, err := tester.MarshalJSON()
+	if err != nil {
+		t.Errorf("Unable to marshal json: %v", err)
+	}
+	jStr := strings.TrimSpace(string(jBytes))
+
+	expected := `{"time":"2023-09-29T13:00:59Z","level":"INFO","msg":"main message","foo@1":"bar"}`
+	if jStr != expected {
+		t.Errorf("Expected:\n%s\nGot:\n%s", expected, jStr)
+	}
+
+	// Uncomment to see the results
+	// t.Error(jStr)
+	// t.Error(tester.String())
+
+	checkRecordForDuplicates(t, tester.Record)
+}
diff --git a/overwrite_handler_test.go b/overwrite_handler_test.go
index 2974990..5db4e16 100644
--- a/overwrite_handler_test.go
+++ b/overwrite_handler_test.go
@@ -88,10 +88,10 @@ func TestOverwriteHandler_CaseInsensitiveDropBuiltinConflicts(t *testing.T) {
 	t.Parallel()
 
 	tester := &testHandler{}
-	h := NewOverwriteHandler(tester, &OverwriteHandlerOptions{
+	h := NewOverwriteMiddleware(&OverwriteHandlerOptions{
 		KeyCompare:                CaseInsensitiveCmp,
 		ResolveBuiltinKeyConflict: DropIfBuiltinKeyConflict,
-	})
+	})(tester)
 
 	log := slog.New(h)
 	log.Info("case insenstive, drop builtin conflict", "arg1", "val1", "ARG1", "val2", slog.MessageKey, "builtin-conflict")