Struct libcnb_test::TestRunner

pub struct TestRunner { /* private fields */ }

Runner for libcnb integration tests.

Dependencies

Integration tests require external tools to be available on the host to run:

• pack
• Docker

Example

use libcnb_test::{TestConfig, BuildpackReference, assert_contains, TestRunner};

TestRunner::default().run_test(
    TestConfig::new("heroku/builder:22", "test-fixtures/app").buildpacks(vec![
        BuildpackReference::Other(String::from("heroku/openjdk")),
        BuildpackReference::Crate,
    ]),
    |context| {
        assert_contains!(context.pack_stdout, "---> Maven Buildpack");
        assert_contains!(context.pack_stdout, "---> Installing Maven");
        assert_contains!(context.pack_stdout, "---> Running mvn package");

        context
            .prepare_container()
            .expose_port(12345)
            .start_with_default_process(|container| {
                assert_eq!(
                    call_test_fixture_service(
                        container.address_for_port(12345).unwrap(),
                        "Hagbard Celine"
                    )
                    .unwrap(),
                    "enileC drabgaH"
                );
            });
    },
);

Implementations

impl TestRunner

pub fn new(tokio_runtime: Runtime, docker: Docker) -> Self

Creates a new runner that uses the given Tokio runtime and Docker connection.

This function is meant for advanced use-cases where fine control over the Tokio runtime and/or Docker connection is required. For the common use-cases, use Runner::default.

pub fn run_test<C: Borrow<TestConfig>, F: FnOnce(TestContext<'_>)>(
    &self,
    config: C,
    f: F
)

Starts a new integration test run.

This function copies the application to a temporary directory, cross-compiles this crate, packages it as a buildpack and then invokes pack to build a new Docker image with the buildpacks specified by the passed TestConfig.

Since this function is supposed to only be used in integration tests, failures are not signalled via Result values. Instead, this function panics whenever an unexpected error occurred to simplify testing code.

Panics

• When the app could not be copied
• When this crate could not be packaged as a buildpack
• When the pack command unexpectedly fails

Example

use libcnb_test::{assert_contains, TestRunner, TestConfig};

TestRunner::default().run_test(
    TestConfig::new("heroku/builder:22", "test-fixtures/app"),
    |context| {
        assert_contains!(context.pack_stdout, "---> Ruby Buildpack");
        assert_contains!(context.pack_stdout, "---> Installing bundler");
        assert_contains!(context.pack_stdout, "---> Installing gems");
    },
)

Trait Implementations

impl Default for TestRunner

fn default() -> Self

Returns the “default value” for a type.