feat: test main

Cargo.toml

@@ -18,3 +18,7 @@ serde_json = { version = "1.0", optional = true }
 [features]
 default = ["serde"]
 serde = ["dep:serde", "dep:serde_json"]
+
+[dev-dependencies]
+assert_cmd = "2.0.13"
+predicates = "3.1.0"

src/lib.rs

@@ -505,7 +505,11 @@ pub fn print_output(
                 println!("{:?} -> {:?}", one_res.path, one_res.modified.unwrap());
             }
         }
-        println!("{} files checked", len);
+        if len == 1 {
+            println!("{} file checked", len);
+        } else {
+            println!("{} files checked", len);
+        }
     } else if options.json.json {
         #[cfg(feature = "serde")]
         {

tests/tests_main.rs

@@ -0,0 +1,33 @@
+#[cfg(test)]
+mod tests {
+    use assert_cmd::prelude::*; // Add methods on commands
+    use predicates::prelude::*; // Used for writing assertions
+    use std::process::Command; // Run programs
+
+    #[test]
+    fn test_main_wrong_path() {
+        let mut cmd = Command::cargo_bin("notox").unwrap();
+
+        cmd.arg("READ ME.md");
+        cmd.assert().failure().stdout(predicate::str::contains(
+            " need to provide at least one valid",
+        ));
+    }
+
+    #[test]
+    fn test_main_normal() {
+        let mut cmd = Command::cargo_bin("notox").unwrap();
+
+        cmd.arg("README.md");
+        cmd.assert()
+            .stdout(predicate::str::contains("1 file checked"));
+    }
+
+    #[test]
+    fn test_main_quiet() {
+        let mut cmd = Command::cargo_bin("notox").unwrap();
+
+        cmd.arg("README.md").arg("-q");
+        cmd.assert().stdout(predicate::str::is_empty());
+    }
+}