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//! This crate makes it easier to write integration tests for CLI applications.
//! It's based on the "workdir" pattern used by BurntSushi's [xsv][] and
//! [ripgrep][] crates, but packaged in an easy-to-reuse form.
//!
//! To use this crate, add the following lines to your `Cargo.toml` file:
//!
//! ```toml
//! [dev-dependencies]
//! # You can replace "*" with the current version of this crate.
//! cli_test_dir = "*"
//! ```
//!
//! You should now be able to write tests in `tests/tests.rs` as follows:
//!
//! ```
//! use cli_test_dir::*;
//!
//! #[test]
//! fn write_output_file() {
//! let testdir = TestDir::new("myapp", "write_output_file");
//! testdir.cmd()
//! .arg("out.txt")
//! .expect_success();
//! testdir.expect_path("out.txt");
//! }
//! ```
//!
//! You can use any options from [`std::process::Command`][Command] to invoke
//! your program.
//!
//! [Command]: https://doc.rust-lang.org/std/process/struct.Command.html
//!
//! ## Testing that the program ran successfully
//!
//! To check that a command succeeds, we can write:
//!
//! ```
//! # use cli_test_dir::*;
//! # #[cfg(unix)]
//! let testdir = TestDir::new("true", "true_succeeds");
//! # #[cfg(windows)]
//! # let testdir = TestDir::new("cmd", "true_succeeds");
//! let mut cmd = testdir.cmd();
//! # #[cfg(windows)]
//! # cmd.args(&["/C", "exit 0"]);
//! cmd.expect_success();
//! ```
//!
//! But this test would fail:
//!
//! ```rust,should_panic
//! # use cli_test_dir::*;
//! // Fails.
//! # #[cfg(unix)]
//! let testdir = TestDir::new("false", "false_succeeds");
//! # #[cfg(windows)]
//! let testdir = TestDir::new("cmd", "false_succeeds");
//! let mut cmd = testdir.cmd();
//! # #[cfg(windows)]
//! # cmd.args(&["/C", "exit 1"]);
//! cmd.expect_success();
//! ```
//!
//! ## Testing that the program exited with an error.
//!
//! Sometimes you want to test that a program fails to run successfully.
//!
//! ```
//! # use cli_test_dir::*;
//! # #[cfg(unix)]
//! let testdir = TestDir::new("false", "false_fails");
//! # #[cfg(windows)]
//! # let testdir = TestDir::new("cmd", "false_fails");
//! let mut cmd = testdir.cmd();
//! # #[cfg(windows)]
//! # cmd.args(&["/C", "exit 1"]);
//! cmd.expect_failure();
//! ```
//!
//! And as you would expect, this test would fail:
//!
//! ```rust,should_panic
//! # use cli_test_dir::*;
//! // Fails.
//! # #[cfg(unix)]
//! let testdir = TestDir::new("true", "true_fails");
//! # #[cfg(windows)]
//! # let testdir = TestDir::new("cmd", "true_fails");
//! let mut cmd = testdir.cmd();
//! # #[cfg(windows)]
//! # cmd.args(&["/C", "exit 0"]);
//! cmd.expect_failure();
//! ```
//!
//! ## File input and output
//!
//! The `src_path` function can be used to build paths relative to the top-level
//! of our crate, and `expect_path` can be used to make sure an output file
//! exists:
//!
//! ```rust
//! # use cli_test_dir::*;
//! # #[cfg(unix)]
//! let testdir = TestDir::new("cp", "cp_copies_files");
//! # #[cfg(windows)]
//! # let testdir = TestDir::new("cmd", "cp_copies_files");
//! let mut cmd = testdir.cmd();
//! # #[cfg(windows)]
//! # cmd.args(&["/C", "copy"]);
//! cmd
//! .arg(testdir.src_path("fixtures/input.txt"))
//! .arg("output.txt")
//! .expect_success();
//! testdir.expect_path("output.txt");
//! ```
//!
//! We can also create the input file manually or look for specific contents in
//! the output file if we wish:
//!
//! ```
//! # use cli_test_dir::*;
//! # #[cfg(unix)]
//! let testdir = TestDir::new("cp", "cp_copies_files_2");
//! # #[cfg(windows)]
//! # let testdir = TestDir::new("cmd", "cp_copies_files_2");
//! let mut cmd = testdir.cmd();
//! # #[cfg(windows)]
//! # cmd.args(&["/C", "copy"]);
//! testdir.create_file("input.txt", "Hello, world!\n");
//! cmd
//! .arg("input.txt")
//! .arg("output.txt")
//! .expect_success();
//! testdir.expect_contains("output.txt", "Hello");
//! testdir.expect_file_contents("output.txt", "Hello, world!\n");
//! ```
//!
//! There are also negative versions of these functions where useful:
//!
//! ```
//! # use cli_test_dir::*;
//! # #[cfg(unix)]
//! let testdir = TestDir::new("cp", "negative_tests");
//! # #[cfg(windows)]
//! # let testdir = TestDir::new("cmd", "negative_tests");
//! let mut cmd = testdir.cmd();
//! # #[cfg(windows)]
//! # cmd.args(&["/C", "copy"]);
//! testdir.create_file("input.txt", "Hello, world!\n");
//! cmd
//! .arg("input.txt")
//! .arg("output.txt")
//! .expect_success();
//! testdir.expect_does_not_contain("output.txt", "Goodbye");
//! testdir.expect_no_such_path("does_not_exist.txt");
//! ```
//!
//! ## Standard input and output
//!
//! We can also test standard input and output:
//!
//! ```
//! # use cli_test_dir::*;
//! # #[cfg(unix)]
//! let testdir = TestDir::new("cat", "cat_passes_data_through");
//! # #[cfg(windows)]
//! # let testdir = TestDir::new("cmd", "type_passes_data_through");
//! let mut cmd = testdir.cmd();
//! # #[cfg(windows)]
//! # cmd.args(&["/C", "findstr x*"]); // https://superuser.com/a/853718
//! let output = cmd
//! .output_with_stdin("Hello\n")
//! .expect_success();
//! assert_eq!(output.stdout_str(), "Hello\n");
//! ```
//!
//! If you wish, you can display a command's output using `tee_output`:
//!
//! ```
//! # use cli_test_dir::*;
//! # #[cfg(unix)]
//! let testdir = TestDir::new("cat", "tee_output_shows_output");
//! # #[cfg(windows)]
//! # let testdir = TestDir::new("cmd", "tee_output_shows_output");
//! let mut cmd = testdir.cmd();
//! # #[cfg(windows)]
//! # cmd.args(&["/C", "findstr x*"]); // https://superuser.com/a/853718
//! let output = cmd
//! .output_with_stdin("Hello\n")
//! // Show `stdout` and `stderr`.
//! .tee_output()
//! .expect_success();
//! assert_eq!(output.stdout_str(), "Hello\n");
//! ```
//!
//! Note that this will currently print out all of `stdout` first, _then_ all of
//! `stderr`, instead of interleaving them normally.
//!
//! To see the output of `tee_output`, you will also need to invoke `cargo` as
//! follows:
//!
//! ```sh
//! cargo test -- --nocapture
//! ```
//!
//! ## Contributing
//!
//! Your feedback and contributions are welcome! Please see
//! [GitHub](https://github.com/emk/subtitles-rs) for details.
//!
//! [ripgrep]: https://github.com/BurntSushi/ripgrep
//! [xsv]: https://github.com/BurntSushi/xsv
use std::{
borrow::Cow,
env, fmt, fs, io,
io::prelude::*,
path::{Path, PathBuf},
process, str,
sync::atomic::{AtomicUsize, Ordering},
thread, time,
};
static TEST_ID: AtomicUsize = AtomicUsize::new(0);
/// This code is inspired by the `WorkDir` pattern that BurntSushi uses to
/// test CLI tools like `ripgrep` and `xsv`.
pub struct TestDir {
bin: PathBuf,
dir: PathBuf,
}
#[cfg(unix)]
fn exe_name(name: &str) -> Cow<str> {
Cow::Borrowed(name)
}
#[cfg(windows)]
fn exe_name(name: &str) -> Cow<str> {
// Maybe something like...
if name.ends_with(".exe") {
Cow::Borrowed(name)
} else {
Cow::Owned(format!("{}.exe", name))
}
}
impl TestDir {
/// Create a new `TestDir` for the current test. You must specify
/// `bin_name` (the name of a binary built by the current crate) and
/// `test_name` (a unique name for the current test).
///
/// If our output directory exists from a previous test run, it will be
/// deleted.
pub fn new(bin_name: &str, test_name: &str) -> TestDir {
let mut bin_dir = env::current_exe()
.expect("Could not find executable")
.parent()
.expect("Could not find parent directory for executable")
.to_path_buf();
if bin_dir.ends_with("deps") {
bin_dir.pop();
}
let id = TEST_ID.fetch_add(1, Ordering::SeqCst);
let dir = bin_dir
.join("integration-tests")
.join(test_name)
.join(format!("{}", id));
if dir.exists() {
fs::remove_dir_all(&dir).expect("Could not remove test output directory");
}
// Work around https://github.com/rust-lang/rust/issues/33707.
let mut err = None;
for _ in 0..10 {
match fs::create_dir_all(&dir) {
Ok(_) => {
err = None;
break;
}
Err(e) => {
err = Some(e);
}
}
thread::sleep(time::Duration::from_millis(500));
}
if let Some(e) = err {
panic!("Could not create test output directory: {}", e);
}
let mut bin = bin_dir.join(&*exe_name(bin_name));
if !bin.exists() {
writeln!(
io::stderr(),
"WARNING: could not find {}, will search PATH",
bin.display()
)
.expect("could not write to stderr");
bin = Path::new(&bin_name).to_owned();
}
TestDir { bin: bin, dir: dir }
}
/// Return a `std::process::Command` object that can be used to execute
/// the binary.
pub fn cmd(&self) -> process::Command {
let mut cmd = process::Command::new(&self.bin);
cmd.current_dir(&self.dir);
cmd
}
/// Construct a path relative to our test directory.
///
/// ```
/// # use cli_test_dir::*;
/// # #[cfg(unix)]
/// let testdir = TestDir::new("touch", "path_builds_paths");
/// # #[cfg(windows)]
/// # let testdir = TestDir::new("cmd", "path_builds_paths");
/// let mut cmd = testdir.cmd();
/// # #[cfg(windows)]
/// # cmd.args(&["/C", "type", "nul", ">"]);
/// cmd
/// .arg("example.txt")
/// .expect_success();
/// assert!(testdir.path("example.txt").exists());
/// ```
pub fn path<P: AsRef<Path>>(&self, path: P) -> PathBuf {
self.dir.join(path)
}
/// Return a path relative to the source directory of the current
/// crate. Useful for finding fixtures.
pub fn src_path<P: AsRef<Path>>(&self, path: P) -> PathBuf {
let cwd = env::current_dir().expect("Could not get current dir");
fs::canonicalize(cwd.join(path)).expect("Could not canonicalize path")
}
/// Create a file in our test directory with the specified contents.
pub fn create_file<P, S>(&self, path: P, contents: S)
where
P: AsRef<Path>,
S: AsRef<[u8]>,
{
let path = self.dir.join(path);
fs::create_dir_all(path.parent().expect("expected parent"))
.expect("could not create directory");
let mut f = fs::File::create(&path).expect("can't create file");
f.write_all(contents.as_ref()).expect("can't write to file");
}
/// If `path` does not point to valid path, fail the current test.
pub fn expect_path<P: AsRef<Path>>(&self, path: P) {
let path = self.dir.join(path);
assert!(path.exists(), "{} should exist", path.display());
}
/// If `path` does not point to valid path, fail the current test.
pub fn expect_no_such_path<P: AsRef<Path>>(&self, path: P) {
let path = self.dir.join(path);
assert!(!path.exists(), "{} should not exist", path.display());
}
/// Verify that the file contains the specified data.
pub fn expect_file_contents<P, S>(&self, path: P, expected: S)
where
P: AsRef<Path>,
S: AsRef<[u8]>,
{
let path = self.dir.join(path);
let expected = expected.as_ref();
self.expect_path(&path);
let mut f = fs::File::open(&path).expect("could not open file");
let mut found = vec![];
f.read_to_end(&mut found).expect("could not read file");
expect_data_eq(path.display(), &found, expected);
}
/// (Internal.) Read a `Path` and return a `String`.
fn read_file(&self, path: &Path) -> String {
self.expect_path(&path);
let mut f = fs::File::open(&path).expect("could not open file");
let mut found = vec![];
f.read_to_end(&mut found).expect("could not read file");
str::from_utf8(&found)
.expect("expected UTF-8 file")
.to_owned()
}
/// Verify that the contents of the file match the specified pattern.
/// Someday this should support `std::str::pattern::Pattern` so that we
/// can support both strings and regular expressions, but that hasn't
/// been stabilized yet.
pub fn expect_contains<P>(&self, path: P, pattern: &str)
where
P: AsRef<Path>,
{
let path = self.dir.join(path);
let contents = self.read_file(&path);
assert!(
contents.contains(pattern),
"expected {} to match {:?}, but it contained {:?}",
path.display(),
pattern,
contents
);
}
/// Verify that the contents of the file do not match the specified pattern.
/// Someday this should support `std::str::pattern::Pattern` so that we can
/// support both strings and regular expressions, but that hasn't been
/// stabilized yet.
pub fn expect_does_not_contain<P>(&self, path: P, pattern: &str)
where
P: AsRef<Path>,
{
let path = self.dir.join(path);
let contents = self.read_file(&path);
assert!(
!contents.contains(pattern),
"expected {} to not match {:?}, but it contained {:?}",
path.display(),
pattern,
contents
);
}
}
/// Internal helper function which compares to blobs of potentially binary data.
fn expect_data_eq<D>(source: D, found: &[u8], expected: &[u8])
where
D: fmt::Display,
{
if found != expected {
// TODO: If the data appears to be actual binary, do a better job
// of printing it.
panic!(
"expected {} to equal {:?}, found {:?}",
source,
String::from_utf8_lossy(expected).as_ref(),
String::from_utf8_lossy(found).as_ref()
);
}
}
/// Extension methods for `std::process::Command`.
pub trait CommandExt {
/// Spawn this command, passing it the specified data on standard
/// input.
fn output_with_stdin<S: AsRef<[u8]>>(
&mut self,
input: S,
) -> io::Result<process::Output>;
}
impl CommandExt for process::Command {
fn output_with_stdin<S>(&mut self, input: S) -> io::Result<process::Output>
where
S: AsRef<[u8]>,
{
let input = input.as_ref().to_owned();
let mut child: process::Child = self
.stdin(process::Stdio::piped())
.stdout(process::Stdio::piped())
.stderr(process::Stdio::piped())
.spawn()
.expect("error running command");
let mut stdin = child.stdin.take().expect("std in is unexpectedly missing");
let worker = thread::spawn(move || {
stdin.write_all(&input).expect("could not write to stdin");
stdin
.flush()
.expect("could not flush data to child's stdin");
});
let result = child.wait_with_output();
worker.join().expect("stdin writer failed");
result
}
}
/// Display command output and return it for examination.
pub trait TeeOutputExt {
/// Display the output of a test command on `stdout` and `stderr`, then return
/// the `Output` object for further processing.
fn tee_output(self) -> io::Result<process::Output>;
}
impl TeeOutputExt for &mut process::Command {
fn tee_output(self) -> io::Result<process::Output> {
self.output().tee_output()
}
}
impl TeeOutputExt for io::Result<process::Output> {
fn tee_output(self) -> io::Result<process::Output> {
let output = self?;
io::stdout().write_all(&output.stdout)?;
io::stderr().write_all(&output.stderr)?;
Ok(output)
}
}
/// Extension methods for `std::process::Output`.
pub trait OutputExt {
/// Get standard output as a `str`.
fn stdout_str(&self) -> &str;
/// Get standard error as a `str`.
fn stderr_str(&self) -> &str;
}
impl OutputExt for process::Output {
fn stdout_str(&self) -> &str {
str::from_utf8(&self.stdout).expect("stdout was not UTF-8 text")
}
fn stderr_str(&self) -> &str {
str::from_utf8(&self.stderr).expect("stderr was not UTF-8 text")
}
}
/// We define `expect_status` on quite a few related types to support
/// different calling patterns.
pub trait ExpectStatus {
/// Expect the child process to succeed, and return a
/// `std::process::Output` object with its output.
fn expect_success(self) -> process::Output;
/// Expect the child process to fail, and return `std::process::Output`
/// object with its output.
fn expect_failure(self) -> process::Output;
}
impl ExpectStatus for process::Output {
fn expect_success(self) -> process::Output {
if !self.status.success() {
io::stdout()
.write_all(&self.stdout)
.expect("could not write to stdout");
io::stderr()
.write_all(&self.stderr)
.expect("could not write to stderr");
panic!("expected command to succeed, got {}", self.status)
}
self
}
fn expect_failure(self) -> process::Output {
if self.status.success() {
io::stdout()
.write_all(&self.stdout)
.expect("could not write to stdout");
io::stderr()
.write_all(&self.stderr)
.expect("could not write to stderr");
panic!("expected command to fail, got {}", self.status)
}
self
}
}
impl<ES: ExpectStatus, E: fmt::Debug> ExpectStatus for Result<ES, E> {
fn expect_success(self) -> process::Output {
// Unwrap the result, fail on error, and pass `expect_success` to
// our wrapped type.
match self {
Ok(es) => es.expect_success(),
Err(err) => panic!("error running command: {:?}", err),
}
}
fn expect_failure(self) -> process::Output {
// Unwrap the result, fail on error, and pass `expect_failure` to
// our wrapped type.
match self {
Ok(es) => es.expect_failure(),
// Note that this means we couldn't _run_ the command (perhaps
// because it doesn't exist or wasn't in our path), not that it
// ran but failed.
Err(err) => panic!("error running command: {:?}", err),
}
}
}
impl<'a> ExpectStatus for &'a mut process::Command {
fn expect_success(self) -> process::Output {
self.output().expect_success()
}
fn expect_failure(self) -> process::Output {
self.output().expect_failure()
}
}
impl ExpectStatus for process::Child {
fn expect_success(self) -> process::Output {
self.wait_with_output().expect_success()
}
fn expect_failure(self) -> process::Output {
self.wait_with_output().expect_failure()
}
}