diff --git a/emseries/src/series.rs b/emseries/src/series.rs
index 71e089f..98f0cb1 100644
--- a/emseries/src/series.rs
+++ b/emseries/src/series.rs
@@ -42,7 +42,7 @@ where
 {
     /// Open a time series database at the specified path. `path` is the full path and filename for
     /// the database.
-    pub fn open(path: &str) -> Result<Series<T>, EmseriesReadError> {
+    pub fn open<P: AsRef<std::path::Path>>(path: P) -> Result<Series<T>, EmseriesReadError> {
         let f = OpenOptions::new()
             .read(true)
             .append(true)
diff --git a/emseries/tests/test_io.rs b/emseries/tests/test_io.rs
index c599369..3f26f16 100644
--- a/emseries/tests/test_io.rs
+++ b/emseries/tests/test_io.rs
@@ -99,8 +99,8 @@ mod test {
     {
         let tmp_file = tempfile::NamedTempFile::new().expect("temporary path created");
         let tmp_path = tmp_file.into_temp_path();
-        let ts: Series<BikeTrip> = Series::open(&tmp_path.to_string_lossy())
-            .expect("the time series should open correctly");
+        let ts: Series<BikeTrip> =
+            Series::open(&tmp_path).expect("the time series should open correctly");
         test(ts);
     }
 
@@ -136,8 +136,8 @@ mod test {
     pub fn can_search_for_an_entry_with_exact_time() {
         run_test(|path| {
             let trips = mk_trips();
-            let mut ts: Series<BikeTrip> = Series::open(&path.to_string_lossy())
-                .expect("expect the time series to open correctly");
+            let mut ts: Series<BikeTrip> =
+                Series::open(&path).expect("expect the time series to open correctly");
 
             for trip in &trips[0..=4] {
                 ts.put(trip.clone()).expect("expect a successful put");
@@ -157,8 +157,8 @@ mod test {
     pub fn can_get_entries_in_time_range() {
         run_test(|path| {
             let trips = mk_trips();
-            let mut ts: Series<BikeTrip> = Series::open(&path.to_string_lossy())
-                .expect("expect the time series to open correctly");
+            let mut ts: Series<BikeTrip> =
+                Series::open(&path).expect("expect the time series to open correctly");
 
             for trip in &trips[0..=4] {
                 ts.put(trip.clone()).expect("expect a successful put");
@@ -186,8 +186,8 @@ mod test {
             let trips = mk_trips();
 
             {
-                let mut ts: Series<BikeTrip> = Series::open(&path.to_string_lossy())
-                    .expect("expect the time series to open correctly");
+                let mut ts: Series<BikeTrip> =
+                    Series::open(&path).expect("expect the time series to open correctly");
 
                 for trip in &trips[0..=4] {
                     ts.put(trip.clone()).expect("expect a successful put");
@@ -195,8 +195,8 @@ mod test {
             }
 
             {
-                let ts: Series<BikeTrip> = Series::open(&path.to_string_lossy())
-                    .expect("expect the time series to open correctly");
+                let ts: Series<BikeTrip> =
+                    Series::open(&path).expect("expect the time series to open correctly");
                 let v: Vec<(&UniqueId, &BikeTrip)> = ts.search_sorted(
                     time_range(
                         DateTimeTz(UTC.with_ymd_and_hms(2011, 10, 31, 0, 0, 0).unwrap()).into(),
@@ -220,8 +220,8 @@ mod test {
             let trips = mk_trips();
 
             {
-                let mut ts: Series<BikeTrip> = Series::open(&path.to_string_lossy())
-                    .expect("expect the time series to open correctly");
+                let mut ts: Series<BikeTrip> =
+                    Series::open(&path).expect("expect the time series to open correctly");
 
                 for trip in &trips[0..=2] {
                     ts.put(trip.clone()).expect("expect a successful put");
@@ -229,8 +229,8 @@ mod test {
             }
 
             {
-                let mut ts: Series<BikeTrip> = Series::open(&path.to_string_lossy())
-                    .expect("expect the time series to open correctly");
+                let mut ts: Series<BikeTrip> =
+                    Series::open(&path).expect("expect the time series to open correctly");
                 let v: Vec<(&UniqueId, &BikeTrip)> = ts.search_sorted(
                     time_range(
                         DateTimeTz(UTC.with_ymd_and_hms(2011, 10, 31, 0, 0, 0).unwrap()).into(),
@@ -248,8 +248,8 @@ mod test {
             }
 
             {
-                let ts: Series<BikeTrip> = Series::open(&path.to_string_lossy())
-                    .expect("expect the time series to open correctly");
+                let ts: Series<BikeTrip> =
+                    Series::open(&path).expect("expect the time series to open correctly");
                 let v: Vec<(&UniqueId, &BikeTrip)> = ts.search_sorted(
                     time_range(
                         DateTimeTz(UTC.with_ymd_and_hms(2011, 10, 31, 0, 0, 0).unwrap()).into(),
@@ -273,8 +273,8 @@ mod test {
         run_test(|path| {
             let trips = mk_trips();
 
-            let mut ts: Series<BikeTrip> = Series::open(&path.to_string_lossy())
-                .expect("expect the time series to open correctly");
+            let mut ts: Series<BikeTrip> =
+                Series::open(&path).expect("expect the time series to open correctly");
 
             ts.put(trips[0].clone()).expect("expect a successful put");
             ts.put(trips[1].clone()).expect("expect a successful put");
@@ -310,8 +310,8 @@ mod test {
             let trips = mk_trips();
 
             {
-                let mut ts: Series<BikeTrip> = Series::open(&path.to_string_lossy())
-                    .expect("expect the time series to open correctly");
+                let mut ts: Series<BikeTrip> =
+                    Series::open(&path).expect("expect the time series to open correctly");
 
                 ts.put(trips[0].clone()).expect("expect a successful put");
                 ts.put(trips[1].clone()).expect("expect a successful put");
@@ -327,8 +327,8 @@ mod test {
             }
 
             {
-                let ts: Series<BikeTrip> = Series::open(&path.to_string_lossy())
-                    .expect("expect the time series to open correctly");
+                let ts: Series<BikeTrip> =
+                    Series::open(&path).expect("expect the time series to open correctly");
 
                 let trips: Vec<(&UniqueId, &BikeTrip)> = ts.records().collect();
                 assert_eq!(trips.len(), 3);
@@ -356,8 +356,8 @@ mod test {
             let trips = mk_trips();
 
             {
-                let mut ts: Series<BikeTrip> = Series::open(&path.to_string_lossy())
-                    .expect("expect the time series to open correctly");
+                let mut ts: Series<BikeTrip> =
+                    Series::open(&path).expect("expect the time series to open correctly");
                 let trip_id = ts.put(trips[0].clone()).expect("expect a successful put");
                 ts.put(trips[1].clone()).expect("expect a successful put");
                 ts.put(trips[2].clone()).expect("expect a successful put");
@@ -368,8 +368,8 @@ mod test {
             }
 
             {
-                let ts: Series<BikeTrip> = Series::open(&path.to_string_lossy())
-                    .expect("expect the time series to open correctly");
+                let ts: Series<BikeTrip> =
+                    Series::open(&path).expect("expect the time series to open correctly");
                 let recs: Vec<(&UniqueId, &BikeTrip)> = ts.records().collect();
                 assert_eq!(recs.len(), 2);
             }