diff --git a/cl/_testmockc/function/in.h b/cl/_testmockc/function/in.h
new file mode 100644
index 00000000..98a8f3dd
--- /dev/null
+++ b/cl/_testmockc/function/in.h
@@ -0,0 +1,5 @@
+unsigned f(int a);
+
+void g();
+
+signed int xprintf(const char* fmt, ...);
diff --git a/cl/blockctx.go b/cl/blockctx.go
index 023e5ce0..147e7197 100644
--- a/cl/blockctx.go
+++ b/cl/blockctx.go
@@ -49,7 +49,7 @@ func (ctx *blockCtx) goNodePos(v clang.Cursor) token.Pos {
 		return token.Pos(int(rg.Begin.Offset) + base)
 	}
 	return token.NoPos */
-	panic("todo")
+	panic("todo: goNodePos")
 }
 
 func (p *blockCtx) getPubName(pfnName *string) (rewritten bool) {
diff --git a/cl/cltest/cltest.go b/cl/cltest/cltest.go
new file mode 100644
index 00000000..e2c8fa64
--- /dev/null
+++ b/cl/cltest/cltest.go
@@ -0,0 +1,63 @@
+/*
+ * Copyright (c) 2026 The XGo Authors (xgo.dev). All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package cltest
+
+import (
+	"os"
+	"path"
+	"strings"
+	"testing"
+)
+
+// -----------------------------------------------------------------------------
+
+// TestFromDir runs testFunc for each subdirectory of relDir. If sel is not empty, only subdirectories
+// whose path contains sel will be tested.
+func TestFromDir(t *testing.T, sel, relDir string, testFunc func(t *testing.T, pkgDir string)) {
+	dir, err := os.Getwd()
+	if err != nil {
+		t.Fatal("Getwd failed:", err)
+	}
+	dir = path.Join(dir, relDir)
+	fis, err := os.ReadDir(dir)
+	if err != nil {
+		t.Fatal("ReadDir failed:", err)
+	}
+	for _, fi := range fis {
+		name := fi.Name()
+		if strings.HasPrefix(name, "_") {
+			continue
+		}
+		t.Run(name, func(t *testing.T) {
+			pkgDir := dir + "/" + name
+			if sel != "" && !strings.Contains(pkgDir, sel) {
+				return
+			}
+			testFunc(t, pkgDir)
+		})
+	}
+}
+
+// -----------------------------------------------------------------------------
+
+// MockNameLookup is a mock implementation of the NameLookup function. It returns a fixed archive
+// path and true for any input.
+func MockNameLookup(manglingName string) (archivePath string, ok bool) {
+	return "libfoo.a", true
+}
+
+// -----------------------------------------------------------------------------
diff --git a/cl/compile.go b/cl/compile.go
index 4ac5d846..f0baef1c 100644
--- a/cl/compile.go
+++ b/cl/compile.go
@@ -56,7 +56,7 @@ func (p *nodeInterp) Position(start token.Pos) token.Position {
 }
 
 func (p *nodeInterp) LoadExpr(v ast.Node) string {
-	panic("todo")
+	panic("todo: nodeInterp.LoadExpr")
 }
 
 // -----------------------------------------------------------------------------
@@ -91,13 +91,16 @@ type Config struct {
 
 	// Reused specifies to reuse the Package instance between processing multiple C/C++ header files.
 	*Reused
+
+	// NameLookup looks up the archive path for a given mangling name. It returns the archive path and a boolean indicating whether the lookup was successful.
+	NameLookup func(manglingName string) (archivePath string, ok bool)
 }
 
 // -----------------------------------------------------------------------------
 
 // Source represents a C/C++ header to compile.
 type Source struct {
-	clang.TranslationUnit
+	TU           clang.TranslationUnit
 	PresumedFile *c.Char
 }
 
@@ -139,7 +142,7 @@ func loadFile(p *gogen.Package, conf *Config, file Source) (pi *PkgInfo, err err
 		pkg: p, cb: p.CB(), fset: p.Fset,
 	}
 	_ = conf
-	clang.VisitChildren(file.Cursor(), func(decl, parent clang.Cursor) clang.ChildVisitResult {
+	clang.VisitChildren(file.TU.Cursor(), func(decl, parent clang.Cursor) clang.ChildVisitResult {
 		compileDecl(ctx, decl)
 		return clang.Continue
 	})
diff --git a/cl/compile_test.go b/cl/compile_test.go
index 6089f847..9ec44369 100644
--- a/cl/compile_test.go
+++ b/cl/compile_test.go
@@ -14,47 +14,64 @@
  * limitations under the License.
  */
 
-package cl
+package cl_test
 
 import (
+	"bytes"
 	"os"
-	"path"
-	"strings"
 	"testing"
+
+	"github.com/goplus/gogen"
+	"github.com/goplus/llcppg/cl"
+	"github.com/goplus/llcppg/cl/cltest"
+	"github.com/goplus/llcppg/clang"
+	"github.com/qiniu/x/test"
 )
 
 // -----------------------------------------------------------------------------
 
-func DoTestFromDir(t *testing.T, sel, relDir string, testFunc func(t *testing.T, pkgDir string)) {
-	dir, err := os.Getwd()
-	if err != nil {
-		t.Fatal("Getwd failed:", err)
+func testDiff(t *testing.T, dir string, outfname string, b *bytes.Buffer, exp any) {
+	if expected, ok := exp.(string); ok {
+		result := b.String()
+		if result != expected {
+			t.Errorf("\nResult:\n%s\nExpected:\n%s\n", result, expected)
+		}
+	} else if test.Diff(t, dir+outfname, b.Bytes(), exp.([]byte)) {
+		t.Error(dir, ": unexpect result")
 	}
-	dir = path.Join(dir, relDir)
-	fis, err := os.ReadDir(dir)
+}
+
+func testGenGo(t *testing.T, pkg *gogen.Package, dir string, exp any) {
+	var b bytes.Buffer
+	err := pkg.WriteTo(&b)
 	if err != nil {
-		t.Fatal("ReadDir failed:", err)
-	}
-	for _, fi := range fis {
-		name := fi.Name()
-		if strings.HasPrefix(name, "_") {
-			continue
-		}
-		t.Run(name, func(t *testing.T) {
-			pkgDir := dir + "/" + name
-			if sel != "" && !strings.Contains(pkgDir, sel) {
-				return
-			}
-			testFunc(t, pkgDir)
-		})
+		t.Fatal("gogen.WriteTo failed:", err)
 	}
+	testDiff(t, dir, "/result.txt", &b, exp)
 }
 
-// -----------------------------------------------------------------------------
-/*
 func testFromDir(t *testing.T, sel, relDir string) {
-	DoTestFromDir(t, sel, relDir, func(t *testing.T, pkgDir string) {
+	cltest.TestFromDir(t, sel, relDir, func(t *testing.T, pkgDir string) {
+		idx := clang.CreateIndex(0, 0)
+		defer idx.Dispose()
+
+		u := idx.ParseTranslationUnit(0, pkgDir+"/in.h", "-x", "c")
+		defer u.Dispose()
+
+		pkg, err := cl.NewPackage("", "foo", cl.Source{TU: u}, &cl.Config{
+			NameLookup: cltest.MockNameLookup,
+		})
+		if err != nil {
+			t.Error("cl.NewPackage:", err)
+			return
+		}
+		exp, _ := os.ReadFile(pkgDir + "/out.go")
+		testGenGo(t, pkg.Package, pkgDir, exp)
 	})
 }
-*/
+
+func _TestMockC(t *testing.T) {
+	testFromDir(t, "", "./_testmockc")
+}
+
 // -----------------------------------------------------------------------------
diff --git a/cl/type_and_var.go b/cl/type_and_var.go
index 48bf8cd7..66aa249b 100644
--- a/cl/type_and_var.go
+++ b/cl/type_and_var.go
@@ -36,7 +36,7 @@ const (
 )
 
 func toType(ctx *blockCtx, typ lc.Type, flags int) types.Type {
-	panic("todo")
+	panic("todo: toType")
 }
 
 // -----------------------------------------------------------------------------
diff --git a/go.mod b/go.mod
index 9556fc18..b31ab324 100644
--- a/go.mod
+++ b/go.mod
@@ -5,4 +5,5 @@ go 1.27.0
 require (
 	github.com/goplus/gogen v1.23.5
 	github.com/goplus/lib v0.5.2
+	github.com/qiniu/x v1.18.3
 )
diff --git a/go.sum b/go.sum
index bd55ec31..f5c46251 100644
--- a/go.sum
+++ b/go.sum
@@ -2,3 +2,5 @@ github.com/goplus/gogen v1.23.5 h1:76w3zmAHI+ECI7bPr0enUd0du9+t1IYyXmp43CbIpSs=
 github.com/goplus/gogen v1.23.5/go.mod h1:Y7ulYW3wonQ3d9er00b0uGFEV/IUZa6okWJZh892ACQ=
 github.com/goplus/lib v0.5.2 h1:BUd3mUwTajDRBHVxMfS/y/hDJ6n/Pxwf6z7ikrOXvkE=
 github.com/goplus/lib v0.5.2/go.mod h1:SgJv3oPqLLHCu0gcL46ejOP3x7/2ry2Jtxu7ta32kp0=
+github.com/qiniu/x v1.18.3 h1:trrBKBNszHGwV8XynnbddJr+A7Vca8/xlWP4F/Z4my8=
+github.com/qiniu/x v1.18.3/go.mod h1:Sx3Wy+0GI9OsX4a53mYj6A0o7mHJ94PUvraqGYb4EIs=