Document and test cargo_toml

src/app_state.rs

@@ -1,9 +1,5 @@
 use anyhow::{bail, Context, Result};
-use crossterm::{
+use crossterm::style::Stylize;
-    style::Stylize,
-    terminal::{Clear, ClearType},
-    ExecutableCommand,
-};
 use serde::Deserialize;
 use std::{
     fs::{self, File},
@@ -13,6 +9,7 @@ use std::{
 };
 
 use crate::{
+    clear_terminal,
     embedded::EMBEDDED_FILES,
     exercise::{Exercise, OUTPUT_CAPACITY},
     info_file::ExerciseInfo,
@@ -33,6 +30,7 @@ pub enum StateFileStatus {
     NotRead,
 }
 
+// Parses parts of the output of `cargo metadata`.
 #[derive(Deserialize)]
 struct CargoMetadata {
     target_directory: PathBuf,
@@ -41,14 +39,18 @@ struct CargoMetadata {
 pub struct AppState {
     current_exercise_ind: usize,
     exercises: Vec<Exercise>,
+    // Caches the number of done exercises to avoid iterating over all exercises every time.
     n_done: u16,
     final_message: String,
+    // Preallocated buffer for reading and writing the state file.
     file_buf: Vec<u8>,
     official_exercises: bool,
+    // Cargo's target directory.
     target_dir: PathBuf,
 }
 
 impl AppState {
+    // Update the app state from the state file.
     fn update_from_file(&mut self) -> StateFileStatus {
         self.file_buf.clear();
         self.n_done = 0;
@@ -98,6 +100,7 @@ impl AppState {
         exercise_infos: Vec<ExerciseInfo>,
         final_message: String,
     ) -> Result<(Self, StateFileStatus)> {
+        // Get the target directory from Cargo.
         let metadata_output = Command::new("cargo")
             .arg("metadata")
             .arg("-q")
@@ -117,31 +120,7 @@ impl AppState {
 
         let exercises = exercise_infos
             .into_iter()
-            .map(|mut exercise_info| {
+            .map(Exercise::from)
-                // Leaking to be able to borrow in the watch mode `Table`.
-                // Leaking is not a problem because the `AppState` instance lives until
-                // the end of the program.
-                let path = exercise_info.path().leak();
-
-                exercise_info.name.shrink_to_fit();
-                let name = exercise_info.name.leak();
-                let dir = exercise_info.dir.map(|mut dir| {
-                    dir.shrink_to_fit();
-                    &*dir.leak()
-                });
-
-                let hint = exercise_info.hint.trim().to_owned();
-
-                Exercise {
-                    dir,
-                    name,
-                    path,
-                    test: exercise_info.test,
-                    strict_clippy: exercise_info.strict_clippy,
-                    hint,
-                    done: false,
-                }
-            })
             .collect::<Vec<_>>();
 
         let mut slf = Self {
@@ -184,6 +163,36 @@ impl AppState {
         &self.target_dir
     }
 
+    // Write the state file.
+    // The file's format is very simple:
+    // - The first line is a comment.
+    // - The second line is an empty line.
+    // - The third line is the name of the current exercise. It must end with `\n` even if there
+    // are no done exercises.
+    // - The fourth line is an empty line.
+    // - All remaining lines are the names of done exercises.
+    fn write(&mut self) -> Result<()> {
+        self.file_buf.clear();
+
+        self.file_buf
+            .extend_from_slice(b"DON'T EDIT THIS FILE!\n\n");
+        self.file_buf
+            .extend_from_slice(self.current_exercise().name.as_bytes());
+        self.file_buf.push(b'\n');
+
+        for exercise in &self.exercises {
+            if exercise.done {
+                self.file_buf.push(b'\n');
+                self.file_buf.extend_from_slice(exercise.name.as_bytes());
+            }
+        }
+
+        fs::write(STATE_FILE_NAME, &self.file_buf)
+            .with_context(|| format!("Failed to write the state file {STATE_FILE_NAME}"))?;
+
+        Ok(())
+    }
+
     pub fn set_current_exercise_ind(&mut self, ind: usize) -> Result<()> {
         if ind >= self.exercises.len() {
             bail!(BAD_INDEX_ERR);
@@ -218,6 +227,8 @@ impl AppState {
         Ok(())
     }
 
+    // Official exercises: Dump the original file from the binary.
+    // Third-party exercises: Reset the exercise file with `git stash`.
     fn reset(&self, ind: usize, dir_name: Option<&str>, path: &str) -> Result<()> {
         if self.official_exercises {
             return EMBEDDED_FILES
@@ -271,6 +282,7 @@ impl AppState {
         Ok(exercise.path)
     }
 
+    // Return the index of the next pending exercise or `None` if all exercises are done.
     fn next_pending_exercise_ind(&self) -> Option<usize> {
         if self.current_exercise_ind == self.exercises.len() - 1 {
             // The last exercise is done.
@@ -293,6 +305,8 @@ impl AppState {
         }
     }
 
+    // Official exercises: Dump the solution file form the binary and return its path.
+    // Third-party exercises: Check if a solution file exists and return its path in that case.
     pub fn current_solution_path(&self) -> Result<Option<String>> {
         if DEBUG_PROFILE {
             return Ok(None);
@@ -328,6 +342,9 @@ impl AppState {
         }
     }
 
+    // Mark the current exercise as done and move on to the next pending exercise if one exists.
+    // If all exercises are marked as done, run all of them to make sure that they are actually
+    // done. If an exercise which is marked as done fails, mark it as pending and continue on it.
     pub fn done_current_exercise(&mut self, writer: &mut StdoutLock) -> Result<ExercisesProgress> {
         let exercise = &mut self.exercises[self.current_exercise_ind];
         if !exercise.done {
@@ -335,7 +352,12 @@ impl AppState {
             self.n_done += 1;
         }
 
-        let Some(ind) = self.next_pending_exercise_ind() else {
+        if let Some(ind) = self.next_pending_exercise_ind() {
+            self.set_current_exercise_ind(ind)?;
+
+            return Ok(ExercisesProgress::Pending);
+        }
+
         writer.write_all(RERUNNING_ALL_EXERCISES_MSG)?;
 
         let mut output = Vec::with_capacity(OUTPUT_CAPACITY);
@@ -362,7 +384,7 @@ impl AppState {
             writeln!(writer, "{}", "ok".green())?;
         }
 
-            writer.execute(Clear(ClearType::All))?;
+        clear_terminal(writer)?;
         writer.write_all(FENISH_LINE.as_bytes())?;
 
         let final_message = self.final_message.trim();
@@ -371,42 +393,7 @@ impl AppState {
             writer.write_all(b"\n")?;
         }
 
-            return Ok(ExercisesProgress::AllDone);
+        Ok(ExercisesProgress::AllDone)
-        };
-
-        self.set_current_exercise_ind(ind)?;
-
-        Ok(ExercisesProgress::Pending)
-    }
-
-    // Write the state file.
-    // The file's format is very simple:
-    // - The first line is a comment.
-    // - The second line is an empty line.
-    // - The third line is the name of the current exercise. It must end with `\n` even if there
-    // are no done exercises.
-    // - The fourth line is an empty line.
-    // - All remaining lines are the names of done exercises.
-    fn write(&mut self) -> Result<()> {
-        self.file_buf.clear();
-
-        self.file_buf
-            .extend_from_slice(b"DON'T EDIT THIS FILE!\n\n");
-        self.file_buf
-            .extend_from_slice(self.current_exercise().name.as_bytes());
-        self.file_buf.push(b'\n');
-
-        for exercise in &self.exercises {
-            if exercise.done {
-                self.file_buf.push(b'\n');
-                self.file_buf.extend_from_slice(exercise.name.as_bytes());
-            }
-        }
-
-        fs::write(STATE_FILE_NAME, &self.file_buf)
-            .with_context(|| format!("Failed to write the state file {STATE_FILE_NAME}"))?;
-
-        Ok(())
     }
 }
 
@@ -441,3 +428,56 @@ const FENISH_LINE: &str = "+----------------------------------------------------
            ▒▒  ▒▒                      ▒▒  ▒▒\x1b[0m
 
 ";
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn dummy_exercise() -> Exercise {
+        Exercise {
+            dir: None,
+            name: "0",
+            path: "exercises/0.rs",
+            test: false,
+            strict_clippy: false,
+            hint: String::new(),
+            done: false,
+        }
+    }
+
+    #[test]
+    fn next_pending_exercise() {
+        let mut app_state = AppState {
+            current_exercise_ind: 0,
+            exercises: vec![dummy_exercise(), dummy_exercise(), dummy_exercise()],
+            n_done: 0,
+            final_message: String::new(),
+            file_buf: Vec::new(),
+            official_exercises: true,
+            target_dir: PathBuf::new(),
+        };
+
+        let mut assert = |done: [bool; 3], expected: [Option<usize>; 3]| {
+            for (exercise, done) in app_state.exercises.iter_mut().zip(done) {
+                exercise.done = done;
+            }
+            for (ind, expected) in expected.into_iter().enumerate() {
+                app_state.current_exercise_ind = ind;
+                assert_eq!(
+                    app_state.next_pending_exercise_ind(),
+                    expected,
+                    "done={done:?}, ind={ind}",
+                );
+            }
+        };
+
+        assert([true, true, true], [None, None, None]);
+        assert([false, false, false], [Some(1), Some(2), Some(0)]);
+        assert([false, true, true], [None, Some(0), Some(0)]);
+        assert([true, false, true], [Some(1), None, Some(1)]);
+        assert([true, true, false], [Some(2), Some(2), None]);
+        assert([true, false, false], [Some(1), Some(2), Some(1)]);
+        assert([false, true, false], [Some(2), Some(2), Some(0)]);
+        assert([false, false, true], [Some(1), Some(0), Some(0)]);
+    }
+}

src/cargo_toml.rs

@@ -2,6 +2,10 @@ use anyhow::{Context, Result};
 
 use crate::info_file::ExerciseInfo;
 
+// Return the start and end index of the content of the list `bin = […]`.
+// bin = [xxxxxxxxxxxxxxxxx]
+//        |start_ind       |
+//                         |end_ind
 pub fn bins_start_end_ind(cargo_toml: &str) -> Result<(usize, usize)> {
     let start_ind = cargo_toml
         .find("bin = [")
@@ -16,6 +20,8 @@ pub fn bins_start_end_ind(cargo_toml: &str) -> Result<(usize, usize)> {
     Ok((start_ind, end_ind))
 }
 
+// Generate and append the content of the `bin` list in `Cargo.toml`.
+// The `exercise_path_prefix` is the prefix of the `path` field of every list entry.
 pub fn append_bins(
     buf: &mut Vec<u8>,
     exercise_infos: &[ExerciseInfo],
@@ -37,6 +43,7 @@ pub fn append_bins(
     }
 }
 
+// Update the `bin` list and leave everything else unchanged.
 pub fn updated_cargo_toml(
     exercise_infos: &[ExerciseInfo],
     current_cargo_toml: &str,
@@ -55,3 +62,61 @@ pub fn updated_cargo_toml(
 
     Ok(updated_cargo_toml)
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_bins_start_end_ind() {
+        assert_eq!(bins_start_end_ind("").ok(), None);
+        assert_eq!(bins_start_end_ind("[]").ok(), None);
+        assert_eq!(bins_start_end_ind("bin = [").ok(), None);
+        assert_eq!(bins_start_end_ind("bin = ]").ok(), None);
+        assert_eq!(bins_start_end_ind("bin = []").ok(), Some((7, 7)));
+        assert_eq!(bins_start_end_ind("bin= []").ok(), None);
+        assert_eq!(bins_start_end_ind("bin =[]").ok(), None);
+        assert_eq!(bins_start_end_ind("bin=[]").ok(), None);
+        assert_eq!(bins_start_end_ind("bin = [\nxxx\n]").ok(), Some((7, 12)));
+    }
+
+    #[test]
+    fn test_bins() {
+        let exercise_infos = [
+            ExerciseInfo {
+                name: String::from("1"),
+                dir: None,
+                test: true,
+                strict_clippy: true,
+                hint: String::new(),
+            },
+            ExerciseInfo {
+                name: String::from("2"),
+                dir: Some(String::from("d")),
+                test: false,
+                strict_clippy: false,
+                hint: String::new(),
+            },
+        ];
+
+        let mut buf = Vec::with_capacity(128);
+        append_bins(&mut buf, &exercise_infos, b"");
+        assert_eq!(
+            buf,
+            br#"
+  { name = "1", path = "exercises/1.rs" },
+  { name = "2", path = "exercises/d/2.rs" },
+"#,
+        );
+
+        assert_eq!(
+            updated_cargo_toml(&exercise_infos, "abc\nbin = [xxx]\n123", b"../").unwrap(),
+            br#"abc
+bin = [
+  { name = "1", path = "../exercises/1.rs" },
+  { name = "2", path = "../exercises/d/2.rs" },
+]
+123"#,
+        );
+    }
+}

src/dev.rs

@@ -15,7 +15,7 @@ pub enum DevCommands {
     New {
         /// The path to create the project in
         path: PathBuf,
-        /// Don't initialize a Git repository in the project directory
+        /// Don't try to initialize a Git repository in the project directory
         #[arg(long)]
         no_git: bool,
     },

src/exercise.rs

@@ -10,6 +10,7 @@ use std::{
 use crate::{
     cmd::{run_cmd, CargoCmd},
     in_official_repo,
+    info_file::ExerciseInfo,
     terminal_link::TerminalFileLink,
     DEBUG_PROFILE,
 };
@@ -104,14 +105,7 @@ impl Exercise {
 
         let test_success = CargoCmd {
             subcommand: "test",
-            args: &[
+            args: &["--", "--color", "always", "--show-output"],
-                "--",
-                "--color",
-                "always",
-                "--show-output",
-                "--format",
-                "pretty",
-            ],
             exercise_name: self.name,
             description: "cargo test …",
             // Hide warnings because they are shown by Clippy.
@@ -132,6 +126,34 @@ impl Exercise {
     }
 }
 
+impl From<ExerciseInfo> for Exercise {
+    fn from(mut exercise_info: ExerciseInfo) -> Self {
+        // Leaking to be able to borrow in the watch mode `Table`.
+        // Leaking is not a problem because the `AppState` instance lives until
+        // the end of the program.
+        let path = exercise_info.path().leak();
+
+        exercise_info.name.shrink_to_fit();
+        let name = exercise_info.name.leak();
+        let dir = exercise_info.dir.map(|mut dir| {
+            dir.shrink_to_fit();
+            &*dir.leak()
+        });
+
+        let hint = exercise_info.hint.trim().to_owned();
+
+        Exercise {
+            dir,
+            name,
+            path,
+            test: exercise_info.test,
+            strict_clippy: exercise_info.strict_clippy,
+            hint,
+            done: false,
+        }
+    }
+}
+
 impl Display for Exercise {
     fn fmt(&self, f: &mut Formatter) -> fmt::Result {
         self.path.fmt(f)

src/main.rs

@@ -1,12 +1,8 @@
 use anyhow::{bail, Context, Result};
 use app_state::StateFileStatus;
 use clap::{Parser, Subcommand};
-use crossterm::{
-    terminal::{Clear, ClearType},
-    ExecutableCommand,
-};
 use std::{
-    io::{self, BufRead, Write},
+    io::{self, BufRead, StdoutLock, Write},
     path::Path,
     process::exit,
 };
@@ -40,6 +36,20 @@ const DEBUG_PROFILE: bool = {
     debug_profile
 };
 
+// The current directory is the official Rustligns repository.
+fn in_official_repo() -> bool {
+    Path::new("dev/rustlings-repo.txt").exists()
+}
+
+fn clear_terminal(stdout: &mut StdoutLock) -> io::Result<()> {
+    stdout.write_all(b"\x1b[H\x1b[2J\x1b[3J")
+}
+
+fn press_enter_prompt() -> io::Result<()> {
+    io::stdin().lock().read_until(b'\n', &mut Vec::new())?;
+    Ok(())
+}
+
 /// Rustlings is a collection of small exercises to get you used to writing and reading Rust code
 #[derive(Parser)]
 #[command(version)]
@@ -54,7 +64,7 @@ struct Args {
 
 #[derive(Subcommand)]
 enum Subcommands {
-    /// Initialize Rustlings
+    /// Initialize the official Rustlings exercises
     Init,
     /// Run a single exercise. Runs the next pending exercise if the exercise name is not specified
     Run {
@@ -76,10 +86,6 @@ enum Subcommands {
     Dev(DevCommands),
 }
 
-fn in_official_repo() -> bool {
-    Path::new("dev/rustlings-repo.txt").exists()
-}
-
 fn main() -> Result<()> {
     let args = Args::parse();
 
@@ -97,7 +103,7 @@ fn main() -> Result<()> {
                 let mut stdout = io::stdout().lock();
                 stdout.write_all(b"This command will create the directory `rustlings/` which will contain the exercises.\nPress ENTER to continue ")?;
                 stdout.flush()?;
-                io::stdin().lock().read_until(b'\n', &mut Vec::new())?;
+                press_enter_prompt()?;
                 stdout.write_all(b"\n")?;
             }
 
@@ -123,19 +129,18 @@ fn main() -> Result<()> {
         info_file.final_message.unwrap_or_default(),
     )?;
 
+    // Show the welcome message if the state file doesn't exist yet.
     if let Some(welcome_message) = info_file.welcome_message {
         match state_file_status {
             StateFileStatus::NotRead => {
                 let mut stdout = io::stdout().lock();
-                stdout.execute(Clear(ClearType::All))?;
+                clear_terminal(&mut stdout)?;
 
                 let welcome_message = welcome_message.trim();
                 write!(stdout, "{welcome_message}\n\nPress ENTER to continue ")?;
                 stdout.flush()?;
-
+                press_enter_prompt()?;
-                io::stdin().lock().read_until(b'\n', &mut Vec::new())?;
+                clear_terminal(&mut stdout)?;
-
-                stdout.execute(Clear(ClearType::All))?;
             }
             StateFileStatus::Read => (),
         }

src/watch/state.rs

@@ -1,13 +1,13 @@
 use anyhow::Result;
 use crossterm::{
     style::{style, Stylize},
-    terminal::{size, Clear, ClearType},
+    terminal::size,
-    ExecutableCommand,
 };
 use std::io::{self, StdoutLock, Write};
 
 use crate::{
     app_state::{AppState, ExercisesProgress},
+    clear_terminal,
     exercise::OUTPUT_CAPACITY,
     progress_bar::progress_bar,
     terminal_link::TerminalFileLink,
@@ -111,7 +111,7 @@ impl<'a> WatchState<'a> {
         // Prevent having the first line shifted.
         self.writer.write_all(b"\n")?;
 
-        self.writer.execute(Clear(ClearType::All))?;
+        clear_terminal(&mut self.writer)?;
 
         self.writer.write_all(&self.output)?;
         self.writer.write_all(b"\n")?;