feat: improve `watch` execution mode

The `watch` command now requires user action to move to the next
exercise.

BREAKING CHANGE: this changes the behavior of `watch`.

Cargo.lock

@@ -204,6 +204,11 @@ name = "fuchsia-zircon-sys"
 version = "0.3.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "glob"
+version = "0.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "indicatif"
 version = "0.9.0"
@@ -605,8 +610,10 @@ dependencies = [
  "assert_cmd 0.11.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "clap 2.33.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "console 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "glob 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "indicatif 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "notify 4.0.12 (registry+https://github.com/rust-lang/crates.io-index)",
+ "regex 1.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.92 (registry+https://github.com/rust-lang/crates.io-index)",
  "toml 0.4.10 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -848,6 +855,7 @@ dependencies = [
 "checksum fuchsia-cprng 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "a06f77d526c1a601b7c4cdd98f54b5eaabffc14d5f2f0296febdc7f357c6d3ba"
 "checksum fuchsia-zircon 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)" = "2e9763c69ebaae630ba35f74888db465e49e259ba1bc0eda7d06f4a067615d82"
 "checksum fuchsia-zircon-sys 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)" = "3dcaa9ae7725d12cdb85b3ad99a434db70b468c09ded17e012d86b5c1010f7a7"
+"checksum glob 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)" = "9b919933a397b79c37e33b77bb2aa3dc8eb6e165ad809e58ff75bc7db2e34574"
 "checksum indicatif 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)" = "a29b2fa6f00010c268bface64c18bb0310aaa70d46a195d5382d288c477fb016"
 "checksum inotify 0.6.1 (registry+https://github.com/rust-lang/crates.io-index)" = "40b54539f3910d6f84fbf9a643efd6e3aa6e4f001426c0329576128255994718"
 "checksum inotify-sys 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)" = "e74a1aa87c59aeff6ef2cc2fa62d41bc43f54952f55652656b18a02fd5e356c0"

Cargo.toml

@@ -10,6 +10,7 @@ indicatif = "0.9.0"
 console = "0.6.2"
 notify = "4.0.0"
 toml = "0.4.10"
+regex = "1.1.6"
 serde = {version = "1.0.10", features = ["derive"]}
 
 [[bin]]
@@ -18,3 +19,4 @@ path = "src/main.rs"
 
 [dev-dependencies]
 assert_cmd = "0.11.0"
+glob = "0.3.0"

exercises/enums/enums1.rs

@@ -1,6 +1,8 @@
 // enums1.rs
 // Make me compile! Scroll down for hints!
 
+// I AM NOT DONE
+
 #[derive(Debug)]
 enum Message {
     // TODO: define a few types of messages as used below

exercises/enums/enums2.rs

@@ -1,6 +1,8 @@
 // enums2.rs
 // Make me compile! Scroll down for hints
 
+// I AM NOT DONE
+
 #[derive(Debug)]
 enum Message {
     // TODO: define the different variants used below

exercises/enums/enums3.rs

@@ -1,6 +1,8 @@
 // enums3.rs
 // Address all the TODOs to make the tests pass!
 
+// I AM NOT DONE
+
 enum Message {
     // TODO: implement the message variant types based on their usage below
 }

exercises/error_handling/errors1.rs

@@ -6,6 +6,8 @@
 // this function to have.
 // Scroll down for hints!!!
 
+// I AM NOT DONE
+
 pub fn generate_nametag_text(name: String) -> Option<String> {
     if name.len() > 0 {
         Some(format!("Hi! My name is {}", name))

exercises/error_handling/errors2.rs

@@ -16,6 +16,8 @@
 // There are at least two ways to implement this that are both correct-- but
 // one is a lot shorter! Scroll down for hints to both ways.
 
+// I AM NOT DONE
+
 use std::num::ParseIntError;
 
 pub fn total_cost(item_quantity: &str) -> Result<i32, ParseIntError> {

exercises/error_handling/errors3.rs

@@ -3,6 +3,8 @@
 // `total_cost` function from the previous exercise. It's not working though!
 // Why not? What should we do to fix it? Scroll for hints!
 
+// I AM NOT DONE
+
 use std::num::ParseIntError;
 
 fn main() {

exercises/error_handling/errorsn.rs

@@ -15,6 +15,8 @@
 //
 // Scroll down for hints :)
 
+// I AM NOT DONE
+
 use std::error;
 use std::fmt;
 use std::io;

exercises/error_handling/option1.rs

@@ -4,6 +4,8 @@
 // on `None`. Handle this in a more graceful way than calling `unwrap`!
 // Scroll down for hints :)
 
+// I AM NOT DONE
+
 pub fn pop_too_much() -> bool {
     let mut list = vec![3];
 

exercises/error_handling/result1.rs

@@ -1,6 +1,8 @@
 // result1.rs
 // Make this test pass! Scroll down for hints :)
 
+// I AM NOT DONE
+
 #[derive(PartialEq, Debug)]
 struct PositiveNonzeroInteger(u64);
 

exercises/functions/functions1.rs

@@ -1,6 +1,8 @@
 // functions1.rs
 // Make me compile! Scroll down for hints :)
 
+// I AM NOT DONE
+
 fn main() {
     call_me();
 }

exercises/functions/functions2.rs

@@ -1,6 +1,8 @@
 // functions2.rs
 // Make me compile! Scroll down for hints :)
 
+// I AM NOT DONE
+
 fn main() {
     call_me(3);
 }

exercises/functions/functions3.rs

@@ -1,6 +1,8 @@
 // functions3.rs
 // Make me compile! Scroll down for hints :)
 
+// I AM NOT DONE
+
 fn main() {
     call_me();
 }

exercises/functions/functions4.rs

@@ -4,6 +4,8 @@
 // This store is having a sale where if the price is an even number, you get
 // 10 (money unit) off, but if it's an odd number, it's 3 (money unit) less.
 
+// I AM NOT DONE
+
 fn main() {
     let original_price = 51;
     println!("Your sale price is {}", sale_price(original_price));

exercises/functions/functions5.rs

@@ -1,6 +1,8 @@
 // functions5.rs
 // Make me compile! Scroll down for hints :)
 
+// I AM NOT DONE
+
 fn main() {
     let answer = square(3);
     println!("The answer is {}", answer);

exercises/if/if1.rs

@@ -1,5 +1,7 @@
 // if1.rs
 
+// I AM NOT DONE
+
 pub fn bigger(a: i32, b: i32) -> i32 {
     // Complete this function to return the bigger number!
     // Do not use:

exercises/macros/macros1.rs

@@ -1,6 +1,8 @@
 // macros1.rs
 // Make me compile! Scroll down for hints :)
 
+// I AM NOT DONE
+
 macro_rules! my_macro {
     () => {
         println!("Check out my macro!");

exercises/macros/macros2.rs

@@ -1,6 +1,8 @@
 // macros2.rs
 // Make me compile! Scroll down for hints :)
 
+// I AM NOT DONE
+
 fn main() {
     my_macro!();
 }

exercises/macros/macros3.rs

@@ -1,6 +1,8 @@
 // macros3.rs
 // Make me compile, without taking the macro out of the module! Scroll down for hints :)
 
+// I AM NOT DONE
+
 mod macros {
     macro_rules! my_macro {
         () => {

exercises/macros/macros4.rs

@@ -1,6 +1,8 @@
 // macros4.rs
 // Make me compile! Scroll down for hints :)
 
+// I AM NOT DONE
+
 macro_rules! my_macro {
     () => {
         println!("Check out my macro!");

exercises/modules/modules1.rs

@@ -1,6 +1,8 @@
 // modules1.rs
 // Make me compile! Scroll down for hints :)
 
+// I AM NOT DONE
+
 mod sausage_factory {
     fn make_sausage() {
         println!("sausage!");

exercises/modules/modules2.rs

@@ -1,6 +1,8 @@
 // modules2.rs
 // Make me compile! Scroll down for hints :)
 
+// I AM NOT DONE
+
 mod delicious_snacks {
     use self::fruits::PEAR as fruit;
     use self::veggies::CUCUMBER as veggie;

exercises/move_semantics/move_semantics1.rs

@@ -1,6 +1,8 @@
 // move_semantics1.rs
 // Make me compile! Scroll down for hints :)
 
+// I AM NOT DONE
+
 fn main() {
     let vec0 = Vec::new();
 

exercises/move_semantics/move_semantics2.rs

@@ -1,6 +1,8 @@
 // move_semantics2.rs
 // Make me compile without changing line 10! Scroll down for hints :)
 
+// I AM NOT DONE
+
 fn main() {
     let vec0 = Vec::new();
 

exercises/move_semantics/move_semantics3.rs

@@ -3,6 +3,8 @@
 // (no lines with multiple semicolons necessary!)
 // Scroll down for hints :)
 
+// I AM NOT DONE
+
 fn main() {
     let vec0 = Vec::new();
 

exercises/move_semantics/move_semantics4.rs

@@ -3,6 +3,8 @@
 // in `fn main`, we instead create it within `fn fill_vec` and transfer the
 // freshly created vector from fill_vec to its caller. Scroll for hints!
 
+// I AM NOT DONE
+
 fn main() {
     let vec0 = Vec::new();
 

exercises/primitive_types/primitive_types1.rs

@@ -2,6 +2,8 @@
 // Fill in the rest of the line that has code missing!
 // No hints, there's no tricks, just get used to typing these :)
 
+// I AM NOT DONE
+
 fn main() {
     // Booleans (`bool`)
 

exercises/primitive_types/primitive_types2.rs

@@ -2,6 +2,8 @@
 // Fill in the rest of the line that has code missing!
 // No hints, there's no tricks, just get used to typing these :)
 
+// I AM NOT DONE
+
 fn main() {
     // Characters (`char`)
 

exercises/primitive_types/primitive_types3.rs

@@ -2,6 +2,8 @@
 // Create an array with at least 100 elements in it where the ??? is. 
 // Scroll down for hints!
 
+// I AM NOT DONE
+
 fn main() {
     let a = ???
 

exercises/primitive_types/primitive_types4.rs

@@ -2,6 +2,8 @@
 // Get a slice out of Array a where the ??? is so that the `if` statement
 // returns true. Scroll down for hints!!
 
+// I AM NOT DONE
+
 #[test]
 fn main() {
     let a = [1, 2, 3, 4, 5];

exercises/primitive_types/primitive_types5.rs

@@ -2,6 +2,8 @@
 // Destructure the `cat` tuple so that the println will work.
 // Scroll down for hints!
 
+// I AM NOT DONE
+
 fn main() {
     let cat = ("Furry McFurson", 3.5);
     let /* your pattern here */ = cat;

exercises/primitive_types/primitive_types6.rs

@@ -3,6 +3,8 @@
 // You can put this right into the `println!` where the ??? is.
 // Scroll down for hints!
 
+// I AM NOT DONE
+
 fn main() {
     let numbers = (1, 2, 3);
     println!("The second number is {}", ???);

exercises/standard_library_types/arc1.rs

@@ -4,6 +4,8 @@
 // somewhere. Try not to create any copies of the `numbers` Vec!
 // Scroll down for hints :)
 
+// I AM NOT DONE
+
 use std::sync::Arc;
 use std::thread;
 

exercises/standard_library_types/iterators2.rs

@@ -5,6 +5,8 @@
 // Step 3. Apply the `capitalize_first` function again to a list, but try and ensure it returns a single string
 // As always, there are hints below!
 
+// I AM NOT DONE
+
 pub fn capitalize_first(input: &str) -> String {
     let mut c = input.chars();
     match c.next() {

exercises/standard_library_types/iterators3.rs

@@ -8,6 +8,8 @@
 // a major hint.
 // Have fun :-)
 
+// I AM NOT DONE
+
 #[derive(Debug, PartialEq, Eq)]
 pub enum DivisionError {
     NotDivisible(NotDivisibleError),

exercises/standard_library_types/iterators4.rs

@@ -1,5 +1,7 @@
 // iterators4.rs
 
+// I AM NOT DONE
+
 pub fn factorial(num: u64) -> u64 {
     // Complete this function to return factorial of num
     // Do not use:

exercises/strings/strings1.rs

@@ -1,6 +1,8 @@
 // strings1.rs
 // Make me compile without changing the function signature! Scroll down for hints :)
 
+// I AM NOT DONE
+
 fn main() {
     let answer = current_favorite_color();
     println!("My current favorite color is {}", answer);

exercises/strings/strings2.rs

@@ -1,6 +1,8 @@
 // strings2.rs
 // Make me compile without changing the function signature! Scroll down for hints :)
 
+// I AM NOT DONE
+
 fn main() {
     let word = String::from("green"); // Try not changing this line :)
     if is_a_color_word(word) {

exercises/structs/structs1.rs

@@ -1,6 +1,8 @@
 // structs1.rs
 // Address all the TODOs to make the tests pass!
 
+// I AM NOT DONE
+
 struct ColorClassicStruct {
     // TODO: Something goes here
 }

exercises/structs/structs2.rs

@@ -2,6 +2,8 @@
 // Address all the TODOs to make the tests pass!
 // No hints, just do it!
 
+// I AM NOT DONE
+
 #[derive(Debug)]
 struct Order {
     name: String,

exercises/test1.rs

@@ -7,6 +7,8 @@
 // more than 40 at once, each apple only costs 1! Write a function that calculates
 // the price of an order of apples given the order amount. No hints this time!
 
+// I AM NOT DONE
+
 // Put your function here!
 // fn ..... {
 

exercises/test2.rs

@@ -7,6 +7,8 @@
 // you think each value is. That is, add either `string_slice` or `string`
 // before the parentheses on each line. If you're right, it will compile!
 
+// I AM NOT DONE
+
 fn string_slice(arg: &str) {
     println!("{}", arg);
 }

exercises/test3.rs

@@ -7,6 +7,8 @@
 // we expect to get when we call `times_two` with a negative number.
 // No hints, you can do this :)
 
+// I AM NOT DONE
+
 pub fn times_two(num: i32) -> i32 {
     num * 2
 }

exercises/test4.rs

@@ -5,6 +5,8 @@
 
 // Write a macro that passes the test! No hints this time, you can do it!
 
+// I AM NOT DONE
+
 fn main() {
     if my_macro!("world!") != "Hello world!" {
         panic!("Oh no! Wrong output!");

exercises/tests/tests1.rs

@@ -6,6 +6,8 @@
 // This test has a problem with it -- make the test compile! Make the test
 // pass! Make the test fail! Scroll down for hints :)
 
+// I AM NOT DONE
+
 #[cfg(test)]
 mod tests {
     #[test]

exercises/tests/tests2.rs

@@ -2,6 +2,8 @@
 // This test has a problem with it -- make the test compile! Make the test
 // pass! Make the test fail! Scroll down for hints :)
 
+// I AM NOT DONE
+
 #[cfg(test)]
 mod tests {
     #[test]

exercises/tests/tests3.rs

@@ -3,6 +3,8 @@
 // the test passes. Then write a second test that tests whether we get the result
 // we expect to get when we call `is_even(5)`. Scroll down for hints!
 
+// I AM NOT DONE
+
 pub fn is_even(num: i32) -> bool {
     num % 2 == 0
 }

exercises/threads/threads1.rs

@@ -5,6 +5,8 @@
 // of "waiting..." and the program ends without timing out the playground,
 // you've got it :)
 
+// I AM NOT DONE
+
 use std::sync::Arc;
 use std::thread;
 use std::time::Duration;

exercises/variables/variables1.rs

@@ -1,6 +1,13 @@
 // variables1.rs
 // Make me compile! Scroll down for hints :)
 
+// About this `I AM NOT DONE` thing:
+// We sometimes encourage you to keep trying things on a given exercise,
+// even after you already figured it out. If you got everything working and
+// feel ready for the next exercise, you the `I AM NOT DONE` comment below.
+
+// I AM NOT DONE
+
 fn main() {
     x = 5;
     println!("x has the value {}", x);

exercises/variables/variables2.rs

@@ -1,6 +1,8 @@
 // variables2.rs
 // Make me compile! Scroll down for hints :)
 
+// I AM NOT DONE
+
 fn main() {
     let x;
     if x == 10 {

exercises/variables/variables3.rs

@@ -1,6 +1,8 @@
 // variables3.rs
 // Make me compile! Scroll down for hints :)
 
+// I AM NOT DONE
+
 fn main() {
     let x = 3;
     println!("Number {}", x);

exercises/variables/variables4.rs

@@ -1,6 +1,8 @@
 // variables4.rs
 // Make me compile! Scroll down for hints :)
 
+// I AM NOT DONE
+
 fn main() {
     let x: i32;
     println!("Number {}", x);

src/exercise.rs

@@ -1,16 +1,20 @@
+use regex::Regex;
 use serde::Deserialize;
 use std::fmt::{self, Display, Formatter};
-use std::fs::remove_file;
+use std::fs::{remove_file, File};
+use std::io::Read;
 use std::path::PathBuf;
 use std::process::{self, Command, Output};
 
 const RUSTC_COLOR_ARGS: &[&str] = &["--color", "always"];
+const I_AM_DONE_REGEX: &str = r"(?m)^\s*///?\s*I\s+AM\s+NOT\s+DONE";
+const CONTEXT: usize = 2;
 
 fn temp_file() -> String {
     format!("./temp_{}", process::id())
 }
 
-#[derive(Deserialize)]
+#[derive(Deserialize, Copy, Clone)]
 #[serde(rename_all = "lowercase")]
 pub enum Mode {
     Compile,
@@ -28,6 +32,19 @@ pub struct Exercise {
     pub mode: Mode,
 }
 
+#[derive(PartialEq, Debug)]
+pub enum State {
+    Done,
+    Pending(Vec<ContextLine>),
+}
+
+#[derive(PartialEq, Debug)]
+pub struct ContextLine {
+    pub line: String,
+    pub number: usize,
+    pub important: bool,
+}
+
 impl Exercise {
     pub fn compile(&self) -> Output {
         match self.mode {
@@ -52,6 +69,48 @@ impl Exercise {
     pub fn clean(&self) {
         let _ignored = remove_file(&temp_file());
     }
+
+    pub fn state(&self) -> State {
+        let mut source_file =
+            File::open(&self.path).expect("We were unable to open the exercise file!");
+
+        let source = {
+            let mut s = String::new();
+            source_file
+                .read_to_string(&mut s)
+                .expect("We were unable to read the exercise file!");
+            s
+        };
+
+        let re = Regex::new(I_AM_DONE_REGEX).unwrap();
+
+        if !re.is_match(&source) {
+            return State::Done;
+        }
+
+        let matched_line_index = source
+            .lines()
+            .enumerate()
+            .filter_map(|(i, line)| if re.is_match(line) { Some(i) } else { None })
+            .next()
+            .expect("This should not happen at all");
+
+        let min_line = ((matched_line_index as i32) - (CONTEXT as i32)).max(0) as usize;
+        let max_line = matched_line_index + CONTEXT;
+
+        let context = source
+            .lines()
+            .enumerate()
+            .filter(|&(i, _)| i >= min_line && i <= max_line)
+            .map(|(i, line)| ContextLine {
+                line: line.to_string(),
+                number: i + 1,
+                important: i == matched_line_index,
+            })
+            .collect();
+
+        State::Pending(context)
+    }
 }
 
 impl Display for Exercise {
@@ -63,7 +122,6 @@ impl Display for Exercise {
 #[cfg(test)]
 mod test {
     use super::*;
-    use std::fs::File;
     use std::path::Path;
 
     #[test]
@@ -76,4 +134,53 @@ mod test {
         exercise.clean();
         assert!(!Path::new(&temp_file()).exists());
     }
+
+    #[test]
+    fn test_pending_state() {
+        let exercise = Exercise {
+            path: PathBuf::from("tests/fixture/state/pending_exercise.rs"),
+            mode: Mode::Compile,
+        };
+
+        let state = exercise.state();
+        let expected = vec![
+            ContextLine {
+                line: "// fake_exercise".to_string(),
+                number: 1,
+                important: false,
+            },
+            ContextLine {
+                line: "".to_string(),
+                number: 2,
+                important: false,
+            },
+            ContextLine {
+                line: "// I AM NOT DONE".to_string(),
+                number: 3,
+                important: true,
+            },
+            ContextLine {
+                line: "".to_string(),
+                number: 4,
+                important: false,
+            },
+            ContextLine {
+                line: "fn main() {".to_string(),
+                number: 5,
+                important: false,
+            },
+        ];
+
+        assert_eq!(state, State::Pending(expected));
+    }
+
+    #[test]
+    fn test_finished_exercise() {
+        let exercise = Exercise {
+            path: PathBuf::from("tests/fixture/state/finished_exercise.rs"),
+            mode: Mode::Compile,
+        };
+
+        assert_eq!(exercise.state(), State::Done);
+    }
 }

src/main.rs

@@ -110,11 +110,11 @@ fn watch(exercises: &[Exercise]) -> notify::Result<()> {
                 DebouncedEvent::Create(b) | DebouncedEvent::Chmod(b) | DebouncedEvent::Write(b) => {
                     if b.extension() == Some(OsStr::new("rs")) && b.exists() {
                         let filepath = b.as_path().canonicalize().unwrap();
-                        let exercise = exercises
+                        let pending_exercises = exercises
                             .iter()
                             .skip_while(|e| !filepath.ends_with(&e.path));
                         clear_screen();
-                        let _ignored = verify(exercise);
+                        let _ignored = verify(pending_exercises);
                     }
                 }
                 _ => {}

src/run.rs

@@ -5,7 +5,9 @@ use indicatif::ProgressBar;
 
 pub fn run(exercise: &Exercise) -> Result<(), ()> {
     match exercise.mode {
-        Mode::Test => test(exercise)?,
+        Mode::Test => {
+            test(exercise)?;
+        }
         Mode::Compile => compile_and_run(exercise)?,
     }
     Ok(())

src/verify.rs

@@ -1,18 +1,21 @@
-use crate::exercise::{Exercise, Mode};
+use crate::exercise::{ContextLine, Exercise, Mode, State};
 use console::{style, Emoji};
 use indicatif::ProgressBar;
 
 pub fn verify<'a>(start_at: impl IntoIterator<Item = &'a Exercise>) -> Result<(), ()> {
     for exercise in start_at {
-        match exercise.mode {
+        let is_done = match exercise.mode {
             Mode::Test => test(&exercise)?,
             Mode::Compile => compile_only(&exercise)?,
+        };
+        if !is_done {
+            return Err(());
         }
     }
     Ok(())
 }
 
-fn compile_only(exercise: &Exercise) -> Result<(), ()> {
+fn compile_only(exercise: &Exercise) -> Result<bool, ()> {
     let progress_bar = ProgressBar::new_spinner();
     progress_bar.set_message(format!("Compiling {}...", exercise).as_str());
     progress_bar.enable_steady_tick(100);
@@ -22,7 +25,12 @@ fn compile_only(exercise: &Exercise) -> Result<(), ()> {
         let formatstr = format!("{} Successfully compiled {}!", Emoji("✅", "✓"), exercise);
         println!("{}", style(formatstr).green());
         exercise.clean();
-        Ok(())
+        if let State::Pending(context) = exercise.state() {
+            print_everything_looks_good(exercise.mode, context);
+            Ok(false)
+        } else {
+            Ok(true)
+        }
     } else {
         let formatstr = format!(
             "{} Compilation of {} failed! Compiler error message:\n",
@@ -36,7 +44,7 @@ fn compile_only(exercise: &Exercise) -> Result<(), ()> {
     }
 }
 
-pub fn test(exercise: &Exercise) -> Result<(), ()> {
+pub fn test(exercise: &Exercise) -> Result<bool, ()> {
     let progress_bar = ProgressBar::new_spinner();
     progress_bar.set_message(format!("Testing {}...", exercise).as_str());
     progress_bar.enable_steady_tick(100);
@@ -52,7 +60,12 @@ pub fn test(exercise: &Exercise) -> Result<(), ()> {
             let formatstr = format!("{} Successfully tested {}!", Emoji("✅", "✓"), exercise);
             println!("{}", style(formatstr).green());
             exercise.clean();
-            Ok(())
+            if let State::Pending(context) = exercise.state() {
+                print_everything_looks_good(exercise.mode, context);
+                Ok(false)
+            } else {
+                Ok(true)
+            }
         } else {
             let formatstr = format!(
                 "{} Testing of {} failed! Please try again. Here's the output:",
@@ -77,3 +90,34 @@ pub fn test(exercise: &Exercise) -> Result<(), ()> {
         Err(())
     }
 }
+
+fn print_everything_looks_good(mode: Mode, context: Vec<ContextLine>) {
+    let success_msg = match mode {
+        Mode::Compile => "The code is compiling!",
+        Mode::Test => "The code is compiling, and the tests pass!",
+    };
+
+    println!("");
+    println!("🎉 🎉  {} 🎉 🎉", success_msg);
+    println!("");
+    println!("You can keep working on this exercise,");
+    println!(
+        "or jump into the next one by removing the {} comment:",
+        style("`I AM NOT DONE`").bold()
+    );
+    println!("");
+    for context_line in context {
+        let formatted_line = if context_line.important {
+            format!("{}", style(context_line.line).bold())
+        } else {
+            format!("{}", context_line.line)
+        };
+
+        println!(
+            "{:>2} {}  {}",
+            style(context_line.number).blue().bold(),
+            style("|").blue(),
+            formatted_line
+        );
+    }
+}

tests/fixture/state/pending_exercise.rs

@@ -0,0 +1,7 @@
+// fake_exercise
+
+// I AM NOT DONE
+
+fn main() {
+
+}

tests/integration_tests.rs

@@ -1,4 +1,7 @@
 use assert_cmd::prelude::*;
+use glob::glob;
+use std::fs::File;
+use std::io::Read;
 use std::process::Command;
 
 #[test]
@@ -105,3 +108,20 @@ fn run_single_test_no_exercise() {
         .assert()
         .code(1);
 }
+
+#[test]
+fn all_exercises_require_confirmation() {
+    for exercise in glob("exercises/**/*.rs").unwrap() {
+        let path = exercise.unwrap();
+        let source = {
+            let mut file = File::open(&path).unwrap();
+            let mut s = String::new();
+            file.read_to_string(&mut s).unwrap();
+            s
+        };
+        source.matches("// I AM NOT DONE").next().expect(&format!(
+            "There should be an `I AM NOT DONE` annotation in {:?}",
+            path
+        ));
+    }
+}