1: Add Rust track exercise "Hello World".

[?]

9Zb2bmkejrNknawUtr3MKvVstZkVDR8x8ritfgZXKrky

Dec 23, 2021, 12:43 PM

ERE2X4MYVDHY7U23UTAFGNDSPVKLWN2D3JO4ET7IP7CXLNFQK4CAC

Dependencies

[2] OTLQVLCV 0: Initialise repository.

Change contents

file addition: rust (d--r------)

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file addition: hello-world (d--r------)

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file addition: tests (d--r------)

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file addition: hello-world.rs (----------)

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#[test]
fn test_hello_world() {
assert_eq!("Hello, World!", hello_world::hello());
}
file addition: src (d--r------)

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file addition: lib.rs (----------)

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// &'static is a "lifetime specifier", something you'll learn more about later
pub fn hello() -> &'static str {
"Goodbye, Mars!"
}
file addition: README.md (----------)

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# Hello World

Welcome to Hello World on Exercism's Rust Track.
If you need help running the tests or submitting your code, check out `HELP.md`.

## Instructions

The classical introductory exercise. Just say "Hello, World!".

["Hello, World!"](http://en.wikipedia.org/wiki/%22Hello,_world!%22_program) is
the traditional first program for beginning programming in a new language
or environment.

The objectives are simple:

- Write a function that returns the string "Hello, World!".
- Run the test suite and make sure that it succeeds.
- Submit your solution and check it at the website.

If everything goes well, you will be ready to fetch your first real exercise.

## Source

### Created by

- @EduardoBautista

### Contributed to by

- @ashleygwilliams
- @ClashTheBunny
- @coriolinus
- @cwhakes
- @dvoytik
- @EduardoBautista
- @efx
- @ErikSchierboom
- @hydhknn
- @IanWhitney
- @ijanos
- @kytrinyx
- @lutostag
- @nfiles
- @petertseng
- @regnerjr
- @rofrol
- @stringparser
- @xakon
- @ZapAnton

### Based on

This is an exercise to introduce users to using Exercism - http://en.wikipedia.org/wiki/%22Hello,_world!%22_program
file addition: HELP.md (----------)

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# Help

## Running the tests

Execute the tests with:

```bash
$ cargo test
```

All but the first test have been ignored. After you get the first test to
pass, open the tests source file which is located in the `tests` directory
and remove the `#[ignore]` flag from the next test and get the tests to pass
again. Each separate test is a function with `#[test]` flag above it.
Continue, until you pass every test.

If you wish to run _only ignored_ tests without editing the tests source file, use:

```bash
$ cargo test -- --ignored
```

If you are using Rust 1.51 or later, you can run _all_ tests with

```bash
$ cargo test -- --include-ignored
```

To run a specific test, for example `some_test`, you can use:

```bash
$ cargo test some_test
```

If the specific test is ignored, use:

```bash
$ cargo test some_test -- --ignored
```

To learn more about Rust tests refer to the online [test documentation][rust-tests].

[rust-tests]: https://doc.rust-lang.org/book/ch11-02-running-tests.html

## Submitting your solution

You can submit your solution using the `exercism submit src/lib.rs` command.
This command will upload your solution to the Exercism website and print the solution page's URL.

It's possible to submit an incomplete solution which allows you to:

- See how others have completed the exercise
- Request help from a mentor

## Need to get help?

If you'd like help solving the exercise, check the following pages:

- The [Rust track's documentation](https://exercism.org/docs/tracks/rust)
- [Exercism's support channel on gitter](https://gitter.im/exercism/support)
- The [Frequently Asked Questions](https://exercism.org/docs/using/faqs)

Should those resources not suffice, you could submit your (incomplete) solution to request mentoring.

## Rust Installation

Refer to the [exercism help page][help-page] for Rust installation and learning
resources.

## Submitting the solution

Generally you should submit all files in which you implemented your solution (`src/lib.rs` in most cases). If you are using any external crates, please consider submitting the `Cargo.toml` file. This will make the review process faster and clearer.

## Feedback, Issues, Pull Requests

The GitHub [track repository][github] is the home for all of the Rust exercises. If you have feedback about an exercise, or want to help implement new exercises, head over there and create an issue. Members of the rust track team are happy to help!

If you want to know more about Exercism, take a look at the [contribution guide].

## Submitting Incomplete Solutions
It's possible to submit an incomplete solution so you can see how others have completed the exercise.

[help-page]: https://exercism.io/tracks/rust/learning
[github]: https://github.com/exercism/rust
[contribution guide]: https://exercism.io/docs/community/contributors
file addition: GETTING_STARTED.md (----------)

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# Getting Started

These exercises lean on Test-Driven Development (TDD), but they're not
an exact match.

The following steps assume that you are in the same directory as the exercise.

You must have Rust installed.
Follow the [Installation chapter in the Rust book](https://doc.rust-lang.org/book/ch01-01-installation.html).
The [Rust language section](http://exercism.io/languages/rust)
section from exercism is also useful.

## Step 1

Run the test suite. It can be run with `cargo`, which is installed with Rust.

```sh
$ cargo test
```

This will compile the `hello-world` crate and run the test, which fails.

```sh
running 1 test
test test_hello_world ... FAILED

failures:

---- test_hello_world stdout ----
thread 'test_hello_world' panicked at 'assertion failed: `(left == right)`
(left: `"Hello, World!"`, right: `"Goodbye, Mars!"`)', tests/hello-world.rs:5

failures:
test_hello_world

test result: FAILED. 0 passed; 1 failed; 0 ignored; 0 measured
```

### Understanding Test Failures

The `test_hello_world` failure states that it is expecting the value,
`"Hello, World!"`, to be returned from `hello()`.
The left side of the assertion (at line 5) should be equal to the right side.

```sh
---- test_hello_world stdout ----
thread 'test_hello_world' panicked at 'assertion failed: `(left == right)`
(left: `"Hello, World!"`, right: `"Goodbye, Mars!"`)', tests/hello-world.rs:5
```

### Fixing the Error

To fix it, open up `src/lib.rs` and change the `hello` function to return
`"Hello, World!"` instead of `"Goodbye, Mars!"`.

```rust
pub fn hello() -> &'static str {
"Hello, World!"
}
```

## Step 2

Run the test again. This time, it will pass.

```sh
running 0 tests

test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured

Running target/debug/deps/hello_world-bd1f06dc726ef14f

running 1 test
test test_hello_world ... ok

test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured

Doc-tests hello-world

running 0 tests

test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured
```

## Submit

Once the test is passing, you can submit your code with the following
command:

```sh
$ exercism submit src/lib.rs
```
file addition: Cargo.toml (----------)

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[package]
edition = "2018"
name = "hello-world"
version = "1.1.0"
file addition: .gitignore (----------)

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# Generated by Cargo
# will have compiled files and executables
/target/
**/*.rs.bk

# Remove Cargo.lock from gitignore if creating an executable, leave it for libraries
# More information here http://doc.crates.io/guide.html#cargotoml-vs-cargolock
Cargo.lock
file addition: .exercism (d--r------)

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file addition: metadata.json (----------)

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{"track":"rust","exercise":"hello-world","id":"9d7d60a79f684e20bc899728e28ca5a8","url":"https://exercism.org/tracks/rust/exercises/hello-world","handle":"nicoty","is_requester":true,"auto_approve":false}
file addition: config.json (----------)

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{
"blurb": "The classical introductory exercise. Just say \"Hello, World!\"",
"authors": [
"EduardoBautista"
],
"contributors": [
"ashleygwilliams",
"ClashTheBunny",
"coriolinus",
"cwhakes",
"dvoytik",
"EduardoBautista",
"efx",
"ErikSchierboom",
"hydhknn",
"IanWhitney",
"ijanos",
"kytrinyx",
"lutostag",
"nfiles",
"petertseng",
"regnerjr",
"rofrol",
"stringparser",
"xakon",
"ZapAnton"
],
"files": {
"solution": [
"src/lib.rs"
],
"test": [
"tests/hello-world.rs"
],
"example": [
".meta/example.rs"
]
},
"source": "This is an exercise to introduce users to using Exercism",
"source_url": "http://en.wikipedia.org/wiki/%22Hello,_world!%22_program"
}