diff --git a/.github/workflows/go.yml b/.github/workflows/go.yml
index cd18a81a..95dd8c98 100644
--- a/.github/workflows/go.yml
+++ b/.github/workflows/go.yml
@@ -12,18 +12,27 @@ on:
 jobs:
 
   test-macos:
-    runs-on: macos-latest
     strategy:
       matrix:
+        os: [macos-latest, macos-12, macos-13]
         llvm: [17]
+    runs-on: ${{ matrix.os }}
     steps:
       - uses: actions/checkout@v4
 
       - name: Update Homebrew
         if: matrix.llvm == 17 # needed as long as LLVM 17 is still fresh
         run: brew update
-      - name: Install LLVM ${{ matrix.llvm }}
-        run: HOMEBREW_NO_AUTO_UPDATE=1 brew install llvm@${{ matrix.llvm }}
+      - name: Install LLVM ${{ matrix.llvm }} and bdw-gc
+        run: |
+          HOMEBREW_NO_AUTO_UPDATE=1 brew install llvm@${{ matrix.llvm }} bdw-gc
+          echo `brew --prefix llvm@${{ matrix.llvm }}`/bin >> $GITHUB_PATH
+    
+      - name: Clang information
+        run: |
+          echo $PATH
+          which clang
+          clang --version
         
       - name: Set up Go
         uses: actions/setup-go@v5
@@ -35,6 +44,14 @@ jobs:
 
       - name: Test
         run: go test -v ./...
+      
+      - name: Install
+        run: go install ./...
+      
+      - name: LLGO tests
+        run: |
+          export LLGOROOT=$PWD
+          bash _test/run.sh
 
   test-linux:
     runs-on: ubuntu-20.04
@@ -44,12 +61,19 @@ jobs:
     steps:
     - uses: actions/checkout@v4
 
-    - name: Install LLVM ${{ matrix.llvm }}
+    - name: Install LLVM ${{ matrix.llvm }} and libgc-dev
       run: |
         echo 'deb http://apt.llvm.org/focal/ llvm-toolchain-focal-${{ matrix.llvm }} main' | sudo tee /etc/apt/sources.list.d/llvm.list
         wget -O - https://apt.llvm.org/llvm-snapshot.gpg.key | sudo apt-key add -
         sudo apt-get update
-        sudo apt-get install --no-install-recommends llvm-${{ matrix.llvm }}-dev
+        sudo apt-get install --no-install-recommends clang-${{ matrix.llvm }} llvm-${{ matrix.llvm }}-dev libgc-dev
+        echo /usr/lib/llvm-${{ matrix.llvm }}/bin >> $GITHUB_PATH
+    
+    - name: Clang information
+      run: |
+        echo $PATH
+        which clang
+        clang --version
 
     - name: Set up Go
       uses: actions/setup-go@v5
@@ -61,6 +85,14 @@ jobs:
 
     - name: Test
       run: go test -v -coverprofile="coverage.txt" -covermode=atomic ./...
+    
+    - name: Install
+      run: go install ./...
+      
+    - name: LLGO tests
+      run: |
+        export LLGOROOT=$PWD
+        bash _test/run.sh
 
     - name: Upload coverage reports to Codecov
       uses: codecov/codecov-action@v4
diff --git a/_test/bdwgc.go b/_test/bdwgc.go
new file mode 100644
index 00000000..01bdcb2f
--- /dev/null
+++ b/_test/bdwgc.go
@@ -0,0 +1,101 @@
+package main
+
+import (
+	"unsafe"
+
+	"github.com/goplus/llgo/_test/testing"
+	"github.com/goplus/llgo/c"
+	"github.com/goplus/llgo/internal/runtime/bdwgc"
+)
+
+// ------ Test malloc ------
+
+func TestMalloc(t *testing.T) {
+	pn := (*int)(bdwgc.Malloc(unsafe.Sizeof(int(0))))
+	*pn = 1 << 30
+	c.Printf(c.Str("value: %d, %x, %p, %p\n"), *pn, *pn, pn, &pn)
+
+	pl := (*int64)(bdwgc.Realloc(c.Pointer(pn), unsafe.Sizeof(int64(0))))
+	*pl = 1 << 60
+	c.Printf(c.Str("value: %lld, %llx, %p, %p\n"), *pl, *pl, pl, &pl)
+
+	bdwgc.Free(c.Pointer(pl))
+}
+
+// ------ Test finalizer ------
+
+const (
+	RETURN_VALUE_FREED = 1 << 31
+)
+
+var called uint = 0
+
+func setReturnValueFreed(pobj c.Pointer, clientData c.Pointer) {
+	called |= RETURN_VALUE_FREED
+	c.Printf(c.Str("called: %x\n"), called)
+}
+
+func setLoopValueFreed(pobj c.Pointer, clientData c.Pointer) {
+	pmask := (*uint)(clientData)
+	called |= *pmask
+	c.Printf(c.Str("called: %x\n"), called)
+}
+
+func isCalled(mask uint) bool {
+	return called&mask != 0
+}
+
+func returnValue() *int {
+	pn := bdwgc.Malloc(unsafe.Sizeof(int(0)))
+	bdwgc.RegisterFinalizer(pn, setReturnValueFreed, nil, nil, nil)
+	return (*int)(pn)
+}
+
+func callFunc() {
+	pn := returnValue()
+	*pn = 1 << 30
+	c.Printf(c.Str("value: %d, %x, %p, %p\n"), *pn, *pn, pn, &pn)
+	bdwgc.Gcollect()
+	check(!isCalled(RETURN_VALUE_FREED), c.Str("finalizer should not be called"))
+}
+
+func loop() {
+	for i := 0; i < 5; i++ {
+		p := bdwgc.Malloc(unsafe.Sizeof(int(0)))
+		pn := (*int)(p)
+		*pn = i
+		c.Printf(c.Str("value: %d, %x, %p, %p\n"), *pn, *pn, pn, &pn)
+		pflag := (*uint)(c.Malloc(unsafe.Sizeof(uint(0))))
+		*pflag = 1 << i
+		bdwgc.RegisterFinalizer(p, setLoopValueFreed, c.Pointer(pflag), nil, nil)
+		bdwgc.Gcollect()
+		check(!isCalled(1<<i), c.Str("finalizer should not be called"))
+		for j := 0; j < i; j++ {
+			check(isCalled(1<<j), c.Str("finalizers of previous objects should be called"))
+		}
+	}
+}
+
+// Clear stack to avoid reference
+func clearStack() {
+	p := c.Alloca(128)
+	c.Memset(p, 0, 128)
+}
+
+func check(b bool, msg *c.Char) {
+	if !b {
+		c.Printf(c.Str("check failed: %s\n"), msg)
+		panic("check failed")
+	}
+}
+
+func TestFinalizer(t *testing.T) {
+	bdwgc.Init()
+
+	callFunc()
+	clearStack()
+	bdwgc.Gcollect()
+	check(isCalled(RETURN_VALUE_FREED), c.Str("finalizer should be called"))
+
+	loop()
+}
diff --git a/_test/main.go b/_test/main.go
new file mode 100644
index 00000000..59869456
--- /dev/null
+++ b/_test/main.go
@@ -0,0 +1,31 @@
+package main
+
+import (
+	"github.com/goplus/llgo/_test/testing"
+	"github.com/goplus/llgo/c"
+)
+
+type TestCase struct {
+	Name string
+	F    func(*testing.T)
+}
+
+func main() {
+	tests := []TestCase{
+		{"TestMalloc", TestMalloc},
+		{"TestFinalizer", TestFinalizer},
+	}
+	if c.Argc == 1 {
+		for _, test := range tests {
+			c.Printf(c.Str("%s\n"), c.AllocaCStr(test.Name))
+		}
+		return
+	}
+	c.Fprintf(c.Stderr, c.Str("arg: %s\n"), c.Index(c.Argv, 1))
+	idx := int(c.Atoi(c.Index(c.Argv, 1)))
+	if idx < 0 || idx >= len(tests) {
+		c.Printf(c.Str("invalid test index %d"), idx)
+		panic("invalid test index")
+	}
+	tests[idx].F(nil)
+}
diff --git a/_test/run.sh b/_test/run.sh
new file mode 100644
index 00000000..407453d8
--- /dev/null
+++ b/_test/run.sh
@@ -0,0 +1,28 @@
+#!/bin/bash
+set -e
+testcmd=/tmp/test
+llgo build -o $testcmd ./_test
+cases=$($testcmd)
+total=$(echo "$cases" | wc -l | tr -d ' ')
+succ=0
+for idx in $(seq 1 $((total))); do
+  case=$(echo "$cases" | sed -n "${idx}p")
+  case_id=$(echo "$case" | cut -d',' -f1)
+  case_name=$(echo "$case" | cut -d',' -f2)
+  echo "=== Test case: $case_name"
+  set +e
+  out=$("$testcmd" "$((idx-1))" 2>&1)
+  exit_code=$?
+  set -e
+  if [ "${exit_code:-0}" -ne 0 ]; then
+    echo "failed: $out"
+  else
+    succ=$((succ+1))
+    echo "passed"
+  fi
+done
+echo "=== Done"
+echo "$succ/$total tests passed"
+if [ "$total" -ne "$succ" ]; then
+  exit 1
+fi
diff --git a/_test/testing/testing.go b/_test/testing/testing.go
new file mode 100644
index 00000000..d4b6029b
--- /dev/null
+++ b/_test/testing/testing.go
@@ -0,0 +1,4 @@
+package testing
+
+type T struct {
+}
diff --git a/c/c.go b/c/c.go
index cfa9a77c..e1071eee 100644
--- a/c/c.go
+++ b/c/c.go
@@ -160,3 +160,6 @@ func GetoptLong(argc Int, argv **Char, optstring *Char, longopts *Option, longin
 func GetoptLongOnly(argc Int, argv **Char, optstring *Char, longopts *Option, longindex *Int) Int
 
 // -----------------------------------------------------------------------------
+
+//go:linkname Atoi C.atoi
+func Atoi(s *Char) Int