[Import] Unit tests added

src/import.rs

@@ -15,3 +15,38 @@ pub fn read_accounts(path: &Path) -> Result<Vec<String>, Box<dyn Error>> {
     }
     Ok(result)
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::fs::{remove_file, File};
+    use std::io::Write;
+    use std::path::PathBuf;
+
+    fn create_test_file() -> PathBuf {
+        let file_path = PathBuf::from("test_accounts.csv");
+        let mut file = File::create(&file_path).unwrap();
+
+        writeln!(file, "Type,Name").unwrap();
+        writeln!(file, "EXPENSE,Coffee").unwrap();
+        writeln!(file, "INCOME,Salary").unwrap();
+        writeln!(file, "EXPENSE,Books").unwrap();
+        writeln!(file, "ASSET,Bank").unwrap();
+
+        file_path
+    }
+
+    #[test]
+    fn test_read_accounts() {
+        let file_path = create_test_file();
+        let accounts = read_accounts(&file_path).unwrap();
+        assert_eq!(accounts, vec!["Coffee", "Books"]);
+        remove_file(file_path).unwrap();
+    }
+
+    #[test]
+    fn test_read_accounts_error() {
+        let path = Path::new("non_existing_file.csv");
+        assert!(read_accounts(path).is_err());
+    }
+}