diff --git a/tests/basic.rs b/tests/basic.rs
index 2980cf1..071894f 100644
--- a/tests/basic.rs
+++ b/tests/basic.rs
@@ -18,7 +18,6 @@ fn test_basic_metal() {
 fn test_basic_opencl() -> Result<(), Box<dyn std::error::Error>> {
     let backend = ForwardType::OpenCL;
     let realesr = std::path::Path::new("tests/assets/realesr.mnn");
-    use mnn::BackendConfig;
 
     let mut net = mnn::Interpreter::from_file(realesr)?;
     net.set_cache_file(realesr.with_extension("cache"), 128)?;
diff --git a/tests/common.rs b/tests/common.rs
index 25f5f27..30b44e0 100644
--- a/tests/common.rs
+++ b/tests/common.rs
@@ -26,8 +26,6 @@ impl AsRef<[u8]> for Model {
 }
 
 pub fn test_basic(backend: ForwardType) -> Result<()> {
-    use mnn::BackendConfig;
-
     let mut net = mnn::Interpreter::from_file("tests/assets/realesr.mnn")?;
     let mut config = ScheduleConfig::new();
     config.set_type(backend);
diff --git a/tests/segfault.rs b/tests/segfault.rs
index ea017ca..eb78fa5 100644
--- a/tests/segfault.rs
+++ b/tests/segfault.rs
@@ -6,14 +6,13 @@ use mnn::*;
 fn test_segfault_case_1_() -> Result<(), Box<dyn std::error::Error>> {
     let backend = ForwardType::OpenCL;
     let realesr = std::path::Path::new("tests/assets/realesr.mnn");
-    use mnn::BackendConfig;
 
     let mut net = mnn::Interpreter::from_file(realesr)?;
     net.set_cache_file(realesr.with_extension("cache"), 128)?;
     let mut config = ScheduleConfig::new();
     config.set_type(backend);
     let mut session = net.create_session(config)?;
-    net.update_cache_file(&mut session);
+    net.update_cache_file(&mut session)?;
 
     net.inputs(&session).iter().for_each(|x| {
         let mut tensor = x.tensor::<f32>().expect("No tensor");