3 files changed, 8 insertions, 39 deletions
diff --git a/lib/test/buffer_writer.go b/lib/test/buffer_writer.go
index 676582f8..c9e3790b 100644
--- a/lib/test/buffer_writer.go
+++ b/lib/test/buffer_writer.go
@@ -36,6 +36,10 @@ func (bw *BufferWriter) Fatalf(format string, args ...any) {
 	fmt.Fprintf(bw, format, args...)
 }
 
+func (bw *BufferWriter) Helper() {
+	// NOOP
+}
+
 // Log write the arguments into buffer.
 func (bw *BufferWriter) Log(args ...any) {
 	fmt.Fprint(bw, args...)
diff --git a/lib/test/test.go b/lib/test/test.go
index 07f9bc20..5a85f58a 100644
--- a/lib/test/test.go
+++ b/lib/test/test.go
@@ -8,42 +8,12 @@ package test
 import (
 	"bytes"
 	"fmt"
-	"runtime"
 
 	"git.sr.ht/~shulhan/pakakeh.go/lib/reflect"
 	"git.sr.ht/~shulhan/pakakeh.go/lib/text"
 	"git.sr.ht/~shulhan/pakakeh.go/lib/text/diff"
 )
 
-func printStackTrace(w Writer, trace []byte) {
-	var (
-		lines int
-		start int
-		end   int
-		x     int
-		b     byte
-		ok    bool
-	)
-
-	for x, b = range trace {
-		if b == '\n' {
-			lines++
-			if lines == 3 {
-				start = x + 1
-			}
-			if lines == 5 {
-				end = x + 1
-				break
-			}
-		}
-	}
-
-	_, ok = w.(*BufferWriter)
-	if !ok {
-		w.Log("\n!!! ERR " + string(trace[start:end]))
-	}
-}
-
 // Assert compare two interfaces: exp and got for equality.
 // If both parameters are not equal, the function will call print and try to
 // describe the position (type and value) where value are not matched and call
@@ -87,12 +57,10 @@ func printStackTrace(w Writer, trace []byte) {
 // LIMITATION: this method does not support recursive pointer, for example a
 // node that point to parent and parent that point back to node again.
 func Assert(w Writer, name string, exp, got interface{}) {
-	var (
-		logp = `Assert`
+	w.Helper()
 
-		err   error
-		trace []byte
-	)
+	var logp = `Assert`
+	var err error
 
 	err = reflect.DoEqual(exp, got)
 	if err == nil {
@@ -103,10 +71,6 @@ func Assert(w Writer, name string, exp, got interface{}) {
 		return
 	}
 
-	trace = make([]byte, 1024)
-	runtime.Stack(trace, false)
-	printStackTrace(w, trace)
-
 	if len(name) == 0 {
 		w.Fatalf(`!!! %s: %s`, logp, err)
 	} else {
diff --git a/lib/test/writer.go b/lib/test/writer.go
index 19dddb97..3d6471d5 100644
--- a/lib/test/writer.go
+++ b/lib/test/writer.go
@@ -11,6 +11,7 @@ type Writer interface {
 	Errorf(format string, args ...any)
 	Fatal(args ...any)
 	Fatalf(format string, args ...any)
+	Helper()
 	Log(args ...any)
 	Logf(format string, args ...any)
 }