Crate assert_cmd[−][src]

Expand description

Assert Command - Easy command initialization and assertions.

assert_cmd aims to simplify the process for doing integration testing of CLIs, including:

Finding your crate’s binary to test
Assert on the result of your program’s run.

Overview

Create a Command:

Command::new(path)
Command::from_std(...)
Command::cargo_bin(name)

Configure a Command:

arg / args
current_dir
env / envs / env_remove / env_clear
write_stdin / pipe_stdin
timeout

Validate a Command:

ok / unwrap / unwrap_err
assert
- success, see Assert
- failure, see Assert
- interrupted, see Assert
- code, see Assert
- stdout, see Assert
- stderr, see Assert
- get_output for everything else, see Assert

Note: Command is provided as a convenience. Extension traits for std::process::Command and Output are provided for interoperability:

Examples

Here’s a trivial example:

use assert_cmd::Command;

let mut cmd = Command::cargo_bin("bin_fixture").unwrap();
cmd.assert().success();

And a little of everything:

use assert_cmd::Command;

let mut cmd = Command::cargo_bin("bin_fixture").unwrap();
let assert = cmd
    .arg("-A")
    .env("stdout", "hello")
    .env("exit", "42")
    .write_stdin("42")
    .assert();
assert
    .failure()
    .code(42)
    .stdout("hello\n");

Relevant crates

Other crates that might be useful in testing command line programs.

escargot for more control over configuring the crate’s binary.
duct for orchestrating multiple processes.
- or commandspec for easier writing of commands
rexpect for testing interactive programs.
assert_fs for filesystem fixtures and assertions.
- or tempfile for scratchpad directories.
dir-diff for testing file side-effects.

Migrating from `assert_cli` v0.6

assert_cmd is the successor to the original assert_cli:

More flexible, reusable assertions (also used by assert_fs).
Can integrate with other process-management crates, like duct.
Addresses several architectural problems.

Key points in migrating from assert_cli:

The command-under-test is run eagerly, with assertions happening immediately.
success() is not implicit and requires being explicitly called.
stdout/stderr aren’t automatically trimmed before being passed to the Predicate.