Update hello-world GETTING_STARTED.md to match simplified exercise

exercises/hello-world/GETTING_STARTED.md

@@ -18,141 +18,73 @@ Run the test suite. It can be run with `cargo`, which is installed with rust.
 $ cargo test
 ```
 
-This will fail, complaining that `hello-world` could not compile.
+This will compile the `hello-world` crate and run the test, which fails.
 
-To fix this, create a new directory called `src`.
-Create a new file called, `lib.rs`, inside the `src` directory.
-
-## Step 2
-
-Run the test again. It will give you a new error, another compile error.
-Our `lib.rs` does not contain any code, specifically the `hello()`
-function that our test is looking for.
-
-### Fixing the Error
-
-To fix it, open up the `src/lib.rs` file and add the following code:
-
-```rust
-pub fn hello(name: Option<&str>) -> String {
-    "".to_string()
-}
 ```
-
-Our test is looking for the `hello()` function from the `hello_world`
-crate. `lib.rs`, by default, is our crate root and our test
-is looking for the `hello()` function there.
-
-The code we are adding to `lib.rs` defines a public function (`pub fn`) that is called "hello".
-The function accepts a `name` as an optional argument (`Option`).
-The function returns a `String`.
-We start by returning an empty string (`"".to_string()`).
-
-## Step 3
-
-Run the test again.
-
-This time, code compilation will pass and we receive actual test failures.
-
-```
-running 3 tests
-test test_other_same_name ... ignored
-test test_sample_name ... ignored
-test test_no_name ... FAILED
+running 1 test
+test test_hello_world ... FAILED
 
 failures:
 
----- test_no_name stdout ----
-thread 'test_no_name' panicked at 'assertion failed: `(left == right)`
-(left: `"Hello, World!"`, right: `""`)', tests/hello-world.rs:5
-
+---- test_hello_world stdout ----
+thread 'test_hello_world' panicked at 'assertion failed: `(left == right)`
+(left: `"Hello, World!"`, right: `"Goodbye, World!"`)', tests/hello-world.rs:5
 
 failures:
-    test_no_name
+    test_hello_world
 
-test result: FAILED. 0 passed; 1 failed; 2 ignored; 0 measured
+test result: FAILED. 0 passed; 1 failed; 0 ignored; 0 measured
 ```
 
 ### Understanding Test Failures
 
-Only one of the tests runs (`test_no_name`) and it fails. The other
-tests are ignored (more on that later).
-
-The `test_no_name` failure states that it is expecting the value,
-`"Hello, World!"`, to be returned from `hello("")`.
+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.
 
 ```
----- test_no_name stdout ----
-thread 'test_no_name' panicked at 'assertion failed: `(left == right)`
-(left: `"Hello, World!"`, right: `""`)', tests/hello-world.rs:5
+---- test_hello_world stdout ----
+thread 'test_hello_world' panicked at 'assertion failed: `(left == right)`
+(left: `"Hello, World!"`, right: `"Goodbye, World!"`)', tests/hello-world.rs:5
 ```
 
-To fix it, let's return `"Hello, World!"`, instead of an empty string
-(`""`) inside our `hello` function.
+### Fixing the Error
+
+To fix it, open up `src/lib.rs` and change the `hello` function to return
+`"Hello, World!"` instead of `"Goodbye, World!"`.
 
 ```rust
-pub fn hello(name: Option<&str>) -> String {
-    "Hello, World!".to_string()
+pub fn hello() -> &'static str {
+    "Hello, World!"
 }
 ```
 
-## Step 4
+## Step 2
 
 Run the test again. This time, it will pass.
 
 ```
-running 3 tests
-test test_other_same_name ... ignored
-test test_sample_name ... ignored
-test test_no_name ... ok
-
-test result: ok. 1 passed; 0 failed; 2 ignored; 0 measured
-
-   Doc-tests hello-world
-
 running 0 tests
 
 test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured
-```
-
-You may have noticed compiler warnings earlier:
 
-```
-Compiling hello-world v0.0.0
-(file:////exercism/exercises/rust/hello-world)
-src/lib.rs:1:14: 1:18 warning: unused variable: `name`, #[warn(unused_variables)] on by default
-src/lib.rs:1 pub fn hello(name: Option<&str>) -> String {
-                          ^~~~
-```
-
-Our `hello` function does not use the `name` argument so the
-compiler is letting us know that we could potentially remove the
-argument from our function (it likes "clean code").
-
-As we make the rest of the tests pass, we will find that we need the `name`
-argument, so don't delete it.
-
-Activate the next test. Open the `tests/hello-world.rs` file.
-Delete the `#[ignore]` line for the `test_sample_name` test.
+     Running target/debug/deps/hello_world-bd1f06dc726ef14f
 
-## Step 5
+running 1 test
+test test_hello_world ... ok
 
-Run the test suite again. Read the test failure and make the test pass.
+test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured
 
-As a reminder, the [rust book](http://doc.rust-lang.org/stable/book/README.html)
-is a good reference for understanding rust.
-The cargo output may also have hints to help you, depending on the errors you get.
-For example, `rustc --explain E0425` will explain unresolved name errors.
+   Doc-tests hello-world
 
-## Wash, Rinse, Repeat
+running 0 tests
 
-Delete one `#[ignore]`  at a time, and make each test pass before you move to
-the next one.
+test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured
+```
 
 ## Submit
 
-When everything is passing, you can submit your code with the following
+Once the test is passing, you can submit your code with the following
 command:
 
 ```