feat: add clear opt with test

Cargo.toml

@@ -10,3 +10,6 @@ description = "A CLI app which can help users automatically add co-author(s) to
 [dependencies]
 clap = { version = "4.1.8", features = ["derive"] }
 inquire = "0.6.0"
+
+[dev-dependencies]
+mockall = "0.11.3"

src/coauthor_repo.rs

@@ -1,5 +1,8 @@
 use std::process::Command;
 
+#[cfg(test)]
+use mockall::{automock, predicate::*};
+#[cfg_attr(test, automock)]
 pub trait CoauthorRepo {
     fn list(&self) -> Vec<String>;
     fn get(&self, key: &str) -> String;

src/commands/mob.rs

@@ -8,10 +8,21 @@ pub struct Mob {
     /// Sets active co-author(s) for pair/mob programming
     #[arg(short='w', long="with", num_args=0.., value_name="COAUTHOR_KEY")]
     with: Option<Vec<String>>,
+    /// Clears mob/pair programming session. Going solo!
+    #[arg(short = 'c', long = "clear")]
+    clear: bool,
 }
 
 impl Mob {
     pub fn handle(&self, coauthor_repo: &dyn CoauthorRepo) {
+        if self.clear {
+            coauthor_repo.deactivate_all();
+        }
+
+        if self.with.is_none() {
+            return;
+        }
+
         let coauthor_keys = self.with.as_ref().unwrap();
 
         match coauthor_keys.len() {
@@ -51,3 +62,25 @@ impl Mob {
         }
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::coauthor_repo::MockCoauthorRepo;
+
+    #[test]
+    fn test_clear_deactivates_all_coauthors() {
+        let mut mock_coauthor_repo = MockCoauthorRepo::new();
+        mock_coauthor_repo
+            .expect_deactivate_all()
+            .once()
+            .return_const({});
+
+        let mob = Mob {
+            with: None,
+            clear: true,
+        };
+
+        mob.handle(&mock_coauthor_repo);
+    }
+}