Fix tests after release of Procfile CNB v3.0.0

[edmorley]

libcnb-test has some tests that make use of the Procfile CNB for testing the start_container() API.

These tests intentionally don't pin to a specific version of the Procfile CNB, so that (a) we don't have to manually update it all the time, (b) we test against what's actually in the builder image and so what people will be using. This is generally fine, since normally there won't be breaking changes in the Procfile CNB that affect our tests.

However, Procfile v3.0.0 was just released with an intentional breaking change to the way that the command vs args are handled.

Specifically, before the Procfile file entry would be set as the process command but now it's set as args.

See:

• Update to buildpack API 0.10, invoke processes via bash buildpacks-procfile#205 (comment)
• heroku/buildpacks-procfile@v2.0.2...v3.0.0#diff-782521a81713992d3a07e85975d367cfac60afc78583133551efcddc2026bd3eL19-R20

As a result, CI for this repo is failing with:

---- starting_containers stdout ----
thread 'starting_containers' panicked at libcnb-test/tests/integration_test.rs:502:21:
assertion failed: `(is empty)`
value (unescaped):
$DESIGNATION: line 1: Hello: command not found


value (escaped): `"$DESIGNATION: line 1: Hello: command not found\n"`

eg:
https://github.com/heroku/libcnb.rs/actions/runs/8079052018/job/22073194983#step:8:256

We'll need to update the test here accordingly:

libcnb.rs/libcnb-test/tests/integration_test.rs

Lines 445 to 513 in 5c78f1d

	fn starting_containers() {
	TestRunner::default().build(
	BuildConfig::new("heroku/builder:22", "tests/fixtures/procfile")
	.buildpacks([BuildpackReference::Other(String::from(PROCFILE_URL))]),
	|context| {
	// Using the default entrypoint and command.
	context.start_container(
	ContainerConfig::new()
	.env("PORT", TEST_PORT.to_string())
	.expose_port(TEST_PORT),
	|container| {
	let address_on_host = container.address_for_port(TEST_PORT);
	let url = format!("http://{}:{}", address_on_host.ip(), address_on_host.port());
	// Retries needed since the server takes a moment to start up.
	let mut attempts_remaining = 5;
	let response = loop {
	let response = ureq::get(&url).call();
	if response.is_ok() || attempts_remaining == 0 {
	break response;
	}
	attempts_remaining -= 1;
	thread::sleep(Duration::from_secs(1));
	}
	.unwrap();
	let body = response.into_string().unwrap();
	assert_contains!(body, "Directory listing for /");
	let server_log_output = container.logs_now();
	assert_contains!(
	server_log_output.stdout,
	&format!("Serving HTTP on 0.0.0.0 port {TEST_PORT}")
	);
	assert_contains!(server_log_output.stderr, "GET /");
	let exec_log_output = container.shell_exec("ps | grep python3");
	assert_empty!(exec_log_output.stderr);
	assert_contains!(exec_log_output.stdout, "python3");
	},
	);
	// Overriding the default entrypoint, but using the default command.
	context.start_container(ContainerConfig::new().entrypoint("worker"), |container| {
	let all_log_output = container.logs_wait();
	assert_empty!(all_log_output.stderr);
	assert_eq!(all_log_output.stdout, "this is the worker process!\n");
	});
	// Overriding both the entrypoint and command.
	context.start_container(
	ContainerConfig::new()
	.entrypoint("echo-args")
	.command(["$GREETING", "$DESIGNATION"])
	.envs([("GREETING", "Hello"), ("DESIGNATION", "World")]),
	|container| {
	let all_log_output = container.logs_wait();
	assert_empty!(all_log_output.stderr);
	assert_eq!(all_log_output.stdout, "Hello World\n");
	},
	);
	let command_output =
	context.run_shell_command("for i in {1..3}; do echo \"${i}\"; done");
	assert_empty!(command_output.stderr);
	assert_eq!(command_output.stdout, "1\n2\n3\n");
	},
	);
	}