diff --git a/pttodoer/src/main.rs b/pttodoer/src/main.rs
index 0dda5a6..2925869 100644
--- a/pttodoer/src/main.rs
+++ b/pttodoer/src/main.rs
@@ -63,7 +63,7 @@ impl Flags {
    }
 }
 
-#[derive(Debug)]
+#[derive(Debug, PartialEq)]
 pub struct DB(Vec<TasksAndMetadata>);
 
 impl DB {
@@ -98,6 +98,10 @@ impl DB {
       Ok(DB(result))
    }
 
+   fn new_empty() -> DB {
+      DB{0: vec![]}
+   }
+
    pub fn incomplete(&self) -> Tasks {
       let mut result = Tasks::new();
       for set in &self.0 {
@@ -115,6 +119,19 @@ impl DB {
    }
 
    pub fn edit(&self) -> Result<DB, String> {
+      self._edit(|cwd: &String| {
+         std::process::Command::new("/bin/sh")
+            .current_dir(cwd)
+            .arg("-c")
+            .arg("vim -p ./*")
+            .spawn()
+            .expect("failed to start vim")
+            .wait()
+            .expect("failed to vim");
+      })
+   }
+
+   fn _edit(&self, edit: impl Fn(&String)) -> Result<DB, String> {
       let d = TempDir::new(&TS::now().to_string()).expect("failed to create a temp dir");
       for set in &self.0 {
          let base = set.file.split("/").last().unwrap().to_string();
@@ -123,19 +140,11 @@ impl DB {
       }
 
       loop {
-         std::process::Command::new("/bin/sh")
-            .current_dir(d.path())
-            .arg("-c")
-            .arg("vim -p ./*")
-            .spawn()
-            .expect("failed to start vim")
-            .wait()
-            .expect("failed to vim");
+         let cwd = d.path().display().to_string();
+         edit(&cwd);
          let mut ok = true;
-         for set in &self.0 {
-            let base = set.file.split("/").last().unwrap().to_string();
-            let f = d.path().join(base);
-            ok = ok && TasksAndMetadata::new(f.display().to_string()).is_ok();
+         for f in std::fs::read_dir(&cwd).expect("failed to list edited files") {
+            ok = ok && TasksAndMetadata::new(f.expect("failed to list edited file").path().display().to_string()).is_ok();
          }
          if ok {
             break;
@@ -143,9 +152,10 @@ impl DB {
       }
 
       let mut result = vec![];
-      for set in &self.0 {
-         let base = set.file.split("/").last().unwrap().to_string();
-         let f = d.path().join(base);
+      for f in std::fs::read_dir(d.path()).expect("failed to list edited files") {
+         let f = f.expect("failed to list edited file");
+         let base = f.path().display().to_string().split("/").last().unwrap().to_string();
+         let set = match{ TODO find self.0.find(path.base(f)) OR init TasksAndMetadata{} }
 
          let edited = TasksAndMetadata::new(f.display().to_string()).expect("failed to read edited tasks");
 
@@ -208,9 +218,53 @@ impl DB {
 }
 
 #[cfg(test)]
-mod test_taskss {
+mod test_db {
    use super::*;
 
+   #[test]
+   fn edit_insert_empty() {
+      let db = new_test_db(0, 0);
+      let db_after = db._edit(|cwd| {
+         assert_eq!(0, std::fs::read_dir(cwd).expect("failed to ls cwd").collect::<Vec<_>>().len());
+         assert_ne!("", cwd);
+
+         let mut f = std::fs::File::create(format!("{}/f", cwd)).expect("failed to open a file in cwd");
+         f.write_all(b"f").expect("failed to write a file in cwd");
+
+         let mut g = std::fs::File::create(format!("{}/g", cwd)).expect("failed to open a file in cwd");
+         g.write_all(b"g: h").expect("failed to write a file in cwd");
+      }).expect("failed to not edit");
+      assert_eq!(2, db.0.len());
+      assert_eq!(1, db.0[0].tasks.len());
+      assert_eq!(1, db.0[1].tasks.len());
+      assert_ne!(db, db_after);
+   }
+
+   #[test]
+   fn edit_noop_empty() {
+      let db = new_test_db(0, 0);
+      let db_after = db._edit(|_| {}).expect("failed to not edit");
+      assert_eq!(0, db.0.len());
+      assert_eq!(db, db_after);
+   }
+
+   fn new_test_db(files: i32, tasks_per_file: i32) -> DB {
+      let mut db = DB::new_empty();
+
+      for i in 0..files {
+         let mut tasks = Tasks::new();
+         for j in 0..tasks_per_file {
+            tasks.0.push(Task::from_string(format!("{{\"hello\": \"world[{}]\"}}", j)));
+         }
+         db.0.push(TasksAndMetadata::new_with(
+            format!("{}.yaml", i),
+            TS::now(),
+            tasks,
+         ));
+      }
+      db
+   }
+
    #[test]
    fn read_dir_files() {
       let db = DB::new("./src/testdata/taskss.d/files.d".to_string()).expect("failed to construct from dir of files");
@@ -236,7 +290,7 @@ mod test_taskss {
    }
 }
 
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, PartialEq)]
 pub struct TasksAndMetadata {
    tasks: Tasks,
    file: String,
@@ -329,7 +383,7 @@ fn file_version(file: String) -> Result<TS, String> {
    }
 }
 
-#[derive(Debug, serde::Serialize, serde::Deserialize, Clone)]
+#[derive(Debug, serde::Serialize, serde::Deserialize, Clone, PartialEq)]
 pub struct Tasks(Vec<Task>);
 
 impl Tasks {