Crate insta_cmd

insta-cmd is an extension to insta that lets you snapshot a command that produces (text) output to stdout and stderr. It takes a Command from the standard library, runs it and snapshots the output alongside the exit code.

use std::process::Command;
use insta_cmd::assert_cmd_snapshot;

assert_cmd_snapshot!(Command::new("echo").arg("Hello World!"));

Testing Binaries

If you want to test binaries from your own project you can use the get_cargo_bin and get_cargo_example functions to retrieve the path to your binary. Note that it’s unlikely that cargo will have built the binary under normal circumstances so you will have to run cargo build --bin my-bin or cargo build --example my-example before.

Afterwards you can test it like this:

use std::process::Command;
use insta_cmd::{assert_cmd_snapshot, get_cargo_bin};

assert_cmd_snapshot!(Command::new(get_cargo_bin("hello")).arg("first arg"));

Passing Stdin

To pass data via stdin and to have it snapshotted alongside, use the pass_stdin extension method. Inside the macro it’s automatically in scope.

use std::process::Command;
use insta_cmd::assert_cmd_snapshot;

assert_cmd_snapshot!(Command::new("cat").arg("-b").pass_stdin("Hello World"));

Macros

• assert_cmd_snapshot
  Runs an spawnable and snapshots the output.

Structs

• Command
  A process builder, providing fine-grained control over how a new process should be spawned.
• StdinCommandDeprecated
  Like Command but sends some input to stdin.

Traits

• Spawn
  Implemented by different types that can be spawned and snapshotted.
• SpawnExt
  Utility methods for spawning.

Functions

• get_cargo_bin
  Helper function to return the path to an executable that cargo is building.
• get_cargo_example
  Helper function to return the path to an example that cargo is building.