tests: unify scratch dir logic

1 files changed, 11 insertions, 2 deletions

diff --git a/src/files.rs b/src/files.rs
index 0ec741e..e27bde6 100644
--- a/src/files.rs
+++ b/src/files.rs
@@ -173,14 +173,23 @@ fn with_suffix(path: &Path, suffix: &str) -> PathBuf {
     PathBuf::from(name)
 }
 
+/// An empty directory for the test `name`: `continuum-<name>-<process ID>` in the
+/// temporary directory, emptied first.
+#[cfg(test)]
+pub(crate) fn scratch_dir(name: &str) -> PathBuf {
+    let dir = std::env::temp_dir().join(format!("continuum-{name}-{}", std::process::id()));
+    let _ = std::fs::remove_dir_all(&dir);
+    std::fs::create_dir_all(&dir).unwrap();
+    dir
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
 
     #[test]
     fn writes_reads_and_counts() {
-        let dir = std::env::temp_dir().join(format!("continuum-files-{}", std::process::id()));
-        std::fs::create_dir_all(&dir).unwrap();
+        let dir = scratch_dir("files");
         let path = dir.join("state.json");
         let files = Files::default();