diff --git a/Cargo.toml b/Cargo.toml
index e506f9bde4..04a961ec01 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -37,6 +37,7 @@ cranelift-wasm = "0.41.0"
 cranelift-native = "0.41.0"
 target-lexicon = "0.4.0"
 pretty_env_logger = "0.3.0"
+tempfile = "3.1.0"
 
 [patch."https://github.com/CraneStation/wasi-common"]
 wasi-common = { path = "." }
diff --git a/build.rs b/build.rs
index c7113d5a29..ff492bdf03 100644
--- a/build.rs
+++ b/build.rs
@@ -113,7 +113,7 @@ fn write_testsuite_tests(out: &mut File, dir_entry: DirEntry, testsuite: &str) -
         "    fn {}() -> Result<(), String> {{",
         avoid_keywords(&stemstr.replace("-", "_"))
     )?;
-    write!(out, "        setup_log();")?;
+    writeln!(out, "        setup_log();")?;
     write!(out, "        let path = std::path::Path::new(\"")?;
     // Write out the string with escape_debug to prevent special characters such
     // as backslash from being reinterpreted.
@@ -129,7 +129,11 @@ fn write_testsuite_tests(out: &mut File, dir_entry: DirEntry, testsuite: &str) -
     let workspace = if no_preopens(testsuite, stemstr) {
         "None"
     } else {
-        "Some(&utils::prepare_workspace(&bin_name)?)"
+        writeln!(
+            out,
+            "        let workspace = utils::prepare_workspace(&bin_name)?;"
+        )?;
+        "Some(workspace.path())"
     };
     writeln!(
         out,
diff --git a/tests/runtime.rs b/tests/runtime.rs
index 6f0db720d9..9c0976166f 100644
--- a/tests/runtime.rs
+++ b/tests/runtime.rs
@@ -1,11 +1,8 @@
 use cranelift_codegen::settings;
+use std::path::Path;
 use wasmtime_jit::Context;
 
-pub fn instantiate<S: AsRef<str>>(
-    data: &[u8],
-    bin_name: S,
-    workspace: Option<S>,
-) -> Result<(), String> {
+pub fn instantiate(data: &[u8], bin_name: &str, workspace: Option<&Path>) -> Result<(), String> {
     // Prepare runtime
     let isa_builder =
         cranelift_native::builder().map_err(|_| "host machine is not a supported target")?;
@@ -14,12 +11,12 @@ pub fn instantiate<S: AsRef<str>>(
     let mut context = Context::with_isa(isa);
     let global_exports = context.get_global_exports();
 
-    let get_preopens = |workspace: Option<S>| -> Result<Vec<_>, String> {
+    let get_preopens = |workspace: Option<&Path>| -> Result<Vec<_>, String> {
         if let Some(workspace) = workspace {
-            let preopen_dir = wasi_common::preopen_dir(workspace.as_ref()).map_err(|e| {
+            let preopen_dir = wasi_common::preopen_dir(workspace).map_err(|e| {
                 format!(
                     "error while preopening directory '{}': {}",
-                    workspace.as_ref(),
+                    workspace.display(),
                     e
                 )
             })?;
@@ -36,7 +33,7 @@ pub fn instantiate<S: AsRef<str>>(
             "",
             global_exports,
             &get_preopens(workspace)?,
-            &[bin_name.as_ref().to_owned(), ".".to_owned()],
+            &[bin_name.to_owned(), ".".to_owned()],
             &[],
         )
         .map_err(|e| format!("error instantiating WASI: {}", e))?,
@@ -46,11 +43,5 @@ pub fn instantiate<S: AsRef<str>>(
     context
         .instantiate_module(None, &data)
         .map(|_| ())
-        .map_err(|e| {
-            format!(
-                "error while processing main module '{}': {}",
-                bin_name.as_ref(),
-                e
-            )
-        })
+        .map_err(|e| format!("error while processing main module '{}': {}", bin_name, e))
 }
diff --git a/tests/utils.rs b/tests/utils.rs
index 1b702e08f5..160412d93a 100644
--- a/tests/utils.rs
+++ b/tests/utils.rs
@@ -1,10 +1,8 @@
-use std::env;
-use std::ffi::OsStr;
 use std::fs;
-use std::path::{Component, Path};
-use std::time::SystemTime;
+use std::path::Path;
+use tempfile::{Builder, TempDir};
 
-pub fn read_wasm<P: AsRef<Path>>(path: P) -> Result<Vec<u8>, String> {
+pub fn read_wasm(path: &Path) -> Result<Vec<u8>, String> {
     let data = fs::read(path).map_err(|err| err.to_string())?;
     if data.starts_with(&[b'\0', b'a', b's', b'm']) {
         Ok(data)
@@ -13,33 +11,20 @@ pub fn read_wasm<P: AsRef<Path>>(path: P) -> Result<Vec<u8>, String> {
     }
 }
 
-pub fn prepare_workspace<S: AsRef<str>>(exe_name: S) -> Result<String, String> {
-    let mut workspace = env::temp_dir();
-    let time_now = SystemTime::now()
-        .duration_since(SystemTime::UNIX_EPOCH)
-        .map_err(|err| err.to_string())?;
-    let subdir = format!(
-        "wasi_common_tests_{}_{}",
-        exe_name.as_ref(),
-        time_now.as_secs()
-    );
-    workspace.push(subdir);
-    fs::create_dir(workspace.as_path()).map_err(|err| err.to_string())?;
-
-    Ok(workspace
-        .as_os_str()
-        .to_str()
-        .ok_or("couldn't convert to str".to_owned())?
-        .to_string())
+pub fn prepare_workspace(exe_name: &str) -> Result<TempDir, String> {
+    let prefix = format!("wasi_common_{}", exe_name);
+    Builder::new()
+        .prefix(&prefix)
+        .tempdir()
+        .map_err(|e| format!("couldn't create workspace in temp files: {}", e))
 }
 
-pub fn extract_exec_name_from_path<P: AsRef<Path>>(path: P) -> Result<String, String> {
-    Ok(path
-        .as_ref()
-        .components()
-        .next_back()
-        .map(Component::as_os_str)
-        .and_then(OsStr::to_str)
-        .ok_or("couldn't convert to str".to_owned())?
-        .to_owned())
+pub fn extract_exec_name_from_path(path: &Path) -> Result<String, String> {
+    path.file_stem()
+        .and_then(|s| s.to_str())
+        .map(String::from)
+        .ok_or(format!(
+            "couldn't extract the file stem from path {}",
+            path.display()
+        ))
 }