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use rand::Rng;
use std::io::Read;
use std::path::Path;
use std::io::Write;
use std::fs::OpenOptions;
use std::io::SeekFrom;
use std::io::Seek;
#[derive(Debug)]
pub struct TestTempFile {
filename: String,
random_number: i32,
final_filename: String,
file: std::fs::File
}
impl Drop for TestTempFile {
fn drop(&mut self) {
self.delete_file();
}
}
impl Write for TestTempFile {
fn write(&mut self, buf: &[u8]) -> std::io::Result<usize> {
self.file.write(buf)
}
fn flush(&mut self) -> std::io::Result<()> {
self.file.flush()
}
fn write_all(&mut self, buf: &[u8]) -> std::io::Result<()> {
self.file.write_all(buf)
}
}
impl Read for TestTempFile {
fn read(&mut self, buf: &mut [u8]) -> std::io::Result<usize> {
self.file.read(buf)
}
}
impl Seek for TestTempFile {
fn seek(&mut self, pos: SeekFrom) -> std::io::Result<u64> { self.file.seek(pos) }
}
impl TestTempFile {
pub fn new(filename: String) -> TestTempFile {
TestTempFile::gen_random_name(filename)
}
fn gen_random_name(filename: String) -> TestTempFile {
let mut rng = rand::thread_rng();
let random_number = rng.gen_range(0, i32::max_value());
let final_filename = format!("_{}_{}", random_number, filename);
let file = OpenOptions::new().
create(true).
write(true).
read(true).
open(final_filename.clone()).unwrap();
TestTempFile {
filename,
random_number,
final_filename,
file
}
}
fn delete_file(&mut self) {
let final_filename = self.final_filename.as_str();
if Path::new(final_filename).exists() {
std::fs::remove_file(final_filename);
}
}
}
#[cfg(test)]
mod tests {
use super::*;
use std::str;
static FILE_NAME: &'static str = "test_file.txt";
#[test]
fn test_constructor() {
let t = TestTempFile::new(String::from(FILE_NAME));
assert_eq!(FILE_NAME, t.filename);
}
#[test]
fn test_write() {
let mut t = TestTempFile::new(String::from(FILE_NAME));
match t.write_all(b"some bytes") {
Ok(_) => assert!(true),
Err(e) => assert!(false, e)
}
}
#[test]
fn test_write_and_read() {
let mut t = TestTempFile::new(String::from(FILE_NAME));
let mut buffer = [0; 10];
let msg = b"some bytes";
match t.write_all(msg) {
Ok(_) => assert!(true),
Err(e) => assert!(false, e)
}
t.seek(SeekFrom::Start(0));
match t.read(&mut buffer[..]) {
Ok(n) => {
assert_eq!(msg,
&buffer[..n],
"Left:{:#?}\nRight:{:#?}\n{:#?}",
msg, &buffer[..n], t)
},
Err(e) => assert!(false, format!("Error:{}\n{:#?}", e.to_string(), t))
}
}
}