Merge pull request #1660 from rust-lang/fix/move-semantics-tests

fix: refactor move semantics 1-4 into tests

exercises/move_semantics/move_semantics1.rs

@@ -5,24 +5,19 @@
 
 // I AM NOT DONE
 
+#[test]
 fn main() {
-    let vec0 = Vec::new();
+    let vec0 = vec![22, 44, 66];
 
     let vec1 = fill_vec(vec0);
 
-    println!("{} has length {} content `{:?}`", "vec1", vec1.len(), vec1);
-
-    vec1.push(88);
-
-    println!("{} has length {} content `{:?}`", "vec1", vec1.len(), vec1);
+    assert_eq!(vec1, vec![22, 44, 66, 88]);
 }
 
 fn fill_vec(vec: Vec<i32>) -> Vec<i32> {
-    let mut vec = vec;
+    let vec = vec;
 
-    vec.push(22);
-    vec.push(44);
-    vec.push(66);
+    vec.push(88);
 
     vec
 }

exercises/move_semantics/move_semantics2.rs

@@ -1,32 +1,26 @@
 // move_semantics2.rs
 //
-// Expected output:
-// vec0 has length 3, with contents `[22, 44, 66]`
-// vec1 has length 4, with contents `[22, 44, 66, 88]`
+// Make the test pass by finding a way to keep both Vecs separate!
 //
 // Execute `rustlings hint move_semantics2` or use the `hint` watch subcommand
 // for a hint.
 
 // I AM NOT DONE
 
+#[test]
 fn main() {
-    let vec0 = Vec::new();
+    let vec0 = vec![22, 44, 66];
 
     let mut vec1 = fill_vec(vec0);
 
-    println!("{} has length {}, with contents: `{:?}`", "vec0", vec0.len(), vec0);
-
-    vec1.push(88);
-
-    println!("{} has length {}, with contents `{:?}`", "vec1", vec1.len(), vec1);
+    assert_eq!(vec0, vec![22, 44, 66]);
+    assert_eq!(vec1, vec![22, 44, 66, 88]);
 }
 
 fn fill_vec(vec: Vec<i32>) -> Vec<i32> {
     let mut vec = vec;
 
-    vec.push(22);
-    vec.push(44);
-    vec.push(66);
+    vec.push(88);
 
     vec
 }

exercises/move_semantics/move_semantics3.rs

@@ -8,22 +8,17 @@
 
 // I AM NOT DONE
 
+#[test]
 fn main() {
-    let vec0 = Vec::new();
+    let vec0 = vec![22, 44, 66];
 
     let mut vec1 = fill_vec(vec0);
 
-    println!("{} has length {} content `{:?}`", "vec1", vec1.len(), vec1);
-
-    vec1.push(88);
-
-    println!("{} has length {} content `{:?}`", "vec1", vec1.len(), vec1);
+    assert_eq!(vec1, vec![22, 44, 66, 88]);
 }
 
 fn fill_vec(vec: Vec<i32>) -> Vec<i32> {
-    vec.push(22);
-    vec.push(44);
-    vec.push(66);
+    vec.push(88);
 
     vec
 }

exercises/move_semantics/move_semantics4.rs

@@ -9,25 +9,21 @@
 
 // I AM NOT DONE
 
+#[test]
 fn main() {
-    let vec0 = Vec::new();
+    let vec0 = vec![22, 44, 66];
 
     let mut vec1 = fill_vec(vec0);
 
-    println!("{} has length {} content `{:?}`", "vec1", vec1.len(), vec1);
-
-    vec1.push(88);
-
-    println!("{} has length {} content `{:?}`", "vec1", vec1.len(), vec1);
+    assert_eq!(vec1, vec![22, 44, 66, 88]);
 }
 
-// `fill_vec()` no longer takes `vec: Vec<i32>` as argument
+// `fill_vec()` no longer takes `vec: Vec<i32>` as argument - don't change this!
 fn fill_vec() -> Vec<i32> {
+    // Instead, let's create and fill the Vec in here - how do you do that?
     let mut vec = vec;
 
-    vec.push(22);
-    vec.push(44);
-    vec.push(66);
+    vec.push(88);
 
     vec
 }

info.toml

@@ -284,9 +284,9 @@ better. What do you think is the more commonly used pattern under Rust developer
 [[exercises]]
 name = "move_semantics1"
 path = "exercises/move_semantics/move_semantics1.rs"
-mode = "compile"
+mode = "test"
 hint = """
-So you've got the "cannot borrow immutable local variable `vec1` as mutable" error on the line
+So you've got the "cannot borrow immutable local variable `vec` as mutable" error on the line
 where we push an element to the vector, right?
 The fix for this is going to be adding one keyword, and the addition is NOT on the line where
 we push to the vector (where the error is).
@@ -296,7 +296,7 @@ Also: Try accessing `vec0` after having called `fill_vec()`. See what happens!""
 [[exercises]]
 name = "move_semantics2"
 path = "exercises/move_semantics/move_semantics2.rs"
-mode = "compile"
+mode = "test"
 hint = """
 When running this exercise for the first time, you'll notice an error about
 "borrow of moved value". In Rust, when an argument is passed to a function and
@@ -309,16 +309,12 @@ Rust provides a couple of different ways to mitigate this issue, feel free to tr
 2. Make `fill_vec` borrow its argument instead of taking ownership of it,
    and then copy the data within the function (`vec.clone()`) in order to return an owned
    `Vec<i32>`.
-3. Or, you could make `fill_vec` *mutably* borrow a reference to its argument (which will need to be
-   mutable), modify it directly, then not return anything. This means that `vec0` will change over the
-   course of the function, and makes `vec1` redundant (make sure to change the parameters of the `println!`
-   statements if you go this route)
 """
 
 [[exercises]]
 name = "move_semantics3"
 path = "exercises/move_semantics/move_semantics3.rs"
-mode = "compile"
+mode = "test"
 hint = """
 The difference between this one and the previous ones is that the first line
 of `fn fill_vec` that had `let mut vec = vec;` is no longer there. You can,
@@ -328,7 +324,7 @@ an existing binding to be a mutable binding instead of an immutable one :)"""
 [[exercises]]
 name = "move_semantics4"
 path = "exercises/move_semantics/move_semantics4.rs"
-mode = "compile"
+mode = "test"
 hint = """
 Stop reading whenever you feel like you have enough direction :) Or try
 doing one step and then fixing the compiler errors that result!
@@ -337,7 +333,7 @@ So the end goal is to:
    - so then `vec0` doesn't exist, so we can't pass it to `fill_vec`
    - `fill_vec` has had its signature changed, which our call should reflect
    - since we're not creating a new vec in `main` anymore, we need to create
-     a new vec in `fill_vec`, similarly to the way we did in `main`"""
+     a new vec in `fill_vec`, and fill it with the expected values"""
 
 [[exercises]]
 name = "move_semantics5"