diff --git a/api/Cargo.toml b/api/Cargo.toml
index 03315d3a17..d667f12303 100644
--- a/api/Cargo.toml
+++ b/api/Cargo.toml
@@ -20,6 +20,7 @@ half.workspace = true
 ndarray.workspace = true
 
 [dev-dependencies]
+lazy_static = "1.4.0"
 reqwest.workspace = true
 tempfile.workspace = true
 serde_json.workspace = true
diff --git a/api/tests/mobilenet/mod.rs b/api/tests/mobilenet/mod.rs
index 59ee9a15ab..ea62a6a55d 100644
--- a/api/tests/mobilenet/mod.rs
+++ b/api/tests/mobilenet/mod.rs
@@ -1,3 +1,5 @@
+use std::sync::Once;
+
 fn grace_hopper() -> Value {
     let data = std::fs::read("../tests/grace_hopper_3_224_224.f32.raw").unwrap();
     let data: &[f32] = unsafe { std::slice::from_raw_parts(data.as_ptr() as _, 3 * 224 * 224) };
@@ -5,29 +7,29 @@ fn grace_hopper() -> Value {
 }
 
 fn ensure_models() -> anyhow::Result<()> {
-    for (url, file) in [(
-            "https://github.com/onnx/models/raw/main/vision/classification/mobilenet/model/mobilenetv2-7.onnx",
-            "mobilenetv2-7.onnx"),
-            (
-            "https://sfo2.digitaloceanspaces.com/nnef-public/mobilenet_v2_1.0.onnx.nnef.tgz",
-            "mobilenet_v2_1.0.onnx.nnef.tgz")
-    ] {
-        if std::fs::metadata(file).is_err() {
-            let client = reqwest::blocking::Client::new();
-            let model = client.get(url).send()?;
-            std::fs::write(file, model.bytes()?)?;
+    static START: Once = Once::new();
+    START.call_once(|| {
+        for (url, file) in [(
+                "https://github.com/onnx/models/raw/main/vision/classification/mobilenet/model/mobilenetv2-7.onnx",
+                "mobilenetv2-7.onnx"),
+                (
+                "https://sfo2.digitaloceanspaces.com/nnef-public/mobilenet_v2_1.0.onnx.nnef.tgz",
+                "mobilenet_v2_1.0.onnx.nnef.tgz")
+        ] {
+            if std::fs::metadata(file).is_err() {
+                let client = reqwest::blocking::Client::new();
+                let model = client.get(url).send().unwrap();
+                std::fs::write(file, model.bytes().unwrap()).unwrap();
+            }
         }
-    }
+    });
     Ok(())
 }
 
 #[test]
 fn test_onnx() -> anyhow::Result<()> {
     ensure_models()?;
-    let model = onnx()?
-        .model_for_path("mobilenetv2-7.onnx")?
-        .into_optimized()?
-        .into_runnable()?;
+    let model = onnx()?.model_for_path("mobilenetv2-7.onnx")?.into_optimized()?.into_runnable()?;
     let hopper = grace_hopper();
     let result = model.run([hopper])?;
     let result = result[0].view::<f32>()?;
@@ -45,10 +47,7 @@ fn test_onnx() -> anyhow::Result<()> {
 #[test]
 fn test_state() -> anyhow::Result<()> {
     ensure_models()?;
-    let model = onnx()?
-        .model_for_path("mobilenetv2-7.onnx")?
-        .into_optimized()?
-        .into_runnable()?;
+    let model = onnx()?.model_for_path("mobilenetv2-7.onnx")?.into_optimized()?.into_runnable()?;
     let mut state = model.spawn_state()?;
     let hopper = grace_hopper();
     let result = state.run([hopper])?;