diff --git a/__tests__/data/Dockerfile.unsupported b/__tests__/data/Dockerfile.unsupported
new file mode 100644
index 0000000..9a3adf6
--- /dev/null
+++ b/__tests__/data/Dockerfile.unsupported
@@ -0,0 +1 @@
+FROM busybox:latest
diff --git a/__tests__/dockerfile.test.ts b/__tests__/dockerfile.test.ts
index c510aa9..cff91e8 100644
--- a/__tests__/dockerfile.test.ts
+++ b/__tests__/dockerfile.test.ts
@@ -7,3 +7,10 @@ test('load alpine dockerfile', async () => {
   const dockerfile = await load(dockerfilePath)
   expect(dockerfile.name).toBe('alpine:latest')
 })
+
+test('load dockerfile with unsupported package manager', async () => {
+  const dockerfilePath = path.join(__dirname, 'data', 'Dockerfile.unsupported')
+  await expect(load(dockerfilePath)).rejects.toThrow(
+    'Unable to find supported package manager'
+  )
+}, 10000)