Add filelike backend tests and fix inverted behaviour of FileBackend::from_path_or_create_and

src/backend/mod.rs

@@ -148,7 +148,7 @@ impl FileBackend {
         P: AsRef<std::path::Path>,
     {
         Self::from_path_or_create(path).map(|(mut b, exists)| {
-            if exists {
+            if !exists {
                 closure(&mut b.0)
             }
             b
@@ -187,7 +187,7 @@ impl Backend for MemoryBackend {
 mod tests {
     use super::{Backend, FileBackend, MemoryBackend};
     use failure::Fail;
-    use std::io::{Read, Seek, SeekFrom};
+    use std::io::{Read, Seek, SeekFrom, Write};
     use tempfile::NamedTempFile;
 
     #[test]
@@ -218,8 +218,8 @@ mod tests {
     #[cfg_attr(miri, ignore)]
     fn test_file_backend_from_path_existing() {
         let file = NamedTempFile::new().expect("could not create temporary file");
-        let (mut backend, existed) = FileBackend::from_path_or_create(file.path().to_owned())
-            .expect("could not create backend");
+        let (mut backend, existed) =
+            FileBackend::from_path_or_create(file.path()).expect("could not create backend");
         assert!(existed);
         let data = [4, 5, 1, 6, 8, 1];
 
@@ -298,4 +298,42 @@ mod tests {
         backend.put_data(&data).unwrap();
         assert_eq!(backend.get_data().unwrap(), data);
     }
+
+    // If the file already exists, the closure shouldn't be called.
+    #[test]
+    #[cfg_attr(miri, ignore)]
+    fn test_file_backend_create_and_existing_nocall() {
+        let file = NamedTempFile::new().expect("could not create temporary file");
+        let mut backend = FileBackend::from_path_or_create_and(file.path(), |_| {
+            panic!("Closure called but file already existed");
+        })
+        .expect("could not create backend");
+        let data = [4, 5, 1, 6, 8, 1];
+
+        backend.put_data(&data).expect("could not put data");
+        assert_eq!(backend.get_data().expect("could not get data"), data);
+    }
+
+    // If the file does not yet exist, the closure should be called.
+    #[test]
+    #[cfg_attr(miri, ignore)]
+    fn test_file_backend_create_and_new() {
+        let dir = tempfile::tempdir().expect("could not create temporary directory");
+        let mut file_path = dir.path().to_owned();
+        file_path.push("rustbreak_path_db.db");
+        let mut backend = FileBackend::from_path_or_create_and(file_path, |f| {
+            f.write_all(b"this is a new file")
+                .expect("could not write to file")
+        })
+        .expect("could not create backend");
+        assert_eq!(
+            backend.get_data().expect("could not get data"),
+            b"this is a new file"
+        );
+        let data = [4, 5, 1, 6, 8, 1];
+
+        backend.put_data(&data).expect("could not put data");
+        assert_eq!(backend.get_data().expect("could not get data"), data);
+        dir.close().expect("Error while deleting temp directory!");
+    }
 }

src/backend/path.rs

@@ -103,7 +103,7 @@ impl Backend for PathBackend {
 mod tests {
     use super::{Backend, PathBackend};
     use failure::Fail;
-    //use std::any::Any;
+    use std::io::Write;
     use tempfile::NamedTempFile;
 
     #[test]
@@ -164,4 +164,42 @@ mod tests {
         assert_eq!(std::io::ErrorKind::NotFound, io_err.kind());
         dir.close().expect("Error while deleting temp directory!");
     }
+
+    // If the file already exists, the closure shouldn't be called.
+    #[test]
+    #[cfg_attr(miri, ignore)]
+    fn test_path_backend_create_and_existing_nocall() {
+        let file = NamedTempFile::new().expect("could not create temporary file");
+        let mut backend = PathBackend::from_path_or_create_and(file.path().to_owned(), |_| {
+            panic!("Closure called but file already existed");
+        })
+        .expect("could not create backend");
+        let data = [4, 5, 1, 6, 8, 1];
+
+        backend.put_data(&data).expect("could not put data");
+        assert_eq!(backend.get_data().expect("could not get data"), data);
+    }
+
+    // If the file does not yet exist, the closure should be called.
+    #[test]
+    #[cfg_attr(miri, ignore)]
+    fn test_path_backend_create_and_new() {
+        let dir = tempfile::tempdir().expect("could not create temporary directory");
+        let mut file_path = dir.path().to_owned();
+        file_path.push("rustbreak_path_db.db");
+        let mut backend = PathBackend::from_path_or_create_and(file_path, |f| {
+            f.write_all(b"this is a new file")
+                .expect("could not write to file")
+        })
+        .expect("could not create backend");
+        assert_eq!(
+            backend.get_data().expect("could not get data"),
+            b"this is a new file"
+        );
+        let data = [4, 5, 1, 6, 8, 1];
+
+        backend.put_data(&data).expect("could not put data");
+        assert_eq!(backend.get_data().expect("could not get data"), data);
+        dir.close().expect("Error while deleting temp directory!");
+    }
 }