Add a wrapper method to allow mocking terminal size

1 files changed, 21 insertions, 2 deletions

diff --git a/CLI/rust/src/game_of_life/opts/validators.rs b/CLI/rust/src/game_of_life/opts/validators.rs
index 0de7b3f..5ea37e2 100644
--- a/CLI/rust/src/game_of_life/opts/validators.rs
+++ b/CLI/rust/src/game_of_life/opts/validators.rs
@@ -5,11 +5,20 @@
 
 use terminal_size::{terminal_size, Height, Width};
 
+#[cfg(test)]
+use mocktopus::macros::mockable;
+
+/// An internal method used to allow mocking terminal size in tests
+#[cfg_attr(test, mockable)]
+fn terminal_size_wrapper() -> (Width, Height) {
+    terminal_size().unwrap()
+}
+
 /// Validator to check if width configuration can be used
 ///
 /// The maximum width allowed is the current terminal window width
 pub(crate) fn is_fitting_term_width(val: &str) -> Result<(), String> {
-    let (Width(term_width), Height(_)) = terminal_size().unwrap();
+    let (Width(term_width), Height(_)) = terminal_size_wrapper();
     match val.parse::<u16>() {
         Ok(n) if n > 0 && n <= term_width => Ok(()),
         Ok(_) => Err(format!(
@@ -23,24 +32,29 @@ pub(crate) fn is_fitting_term_width(val: &str) -> Result<(), String> {
 #[cfg(test)]
 mod is_fitting_term_width {
     use super::*;
+    use mocktopus::mocking::*;
 
     #[test]
     fn positive_value() {
+        terminal_size_wrapper.mock_safe(|| MockResult::Return((Width(42), Height(42))));
         assert!(is_fitting_term_width("13").is_ok());
     }
 
     #[test]
     fn value_too_large() {
+        terminal_size_wrapper.mock_safe(|| MockResult::Return((Width(42), Height(42))));
         assert!(is_fitting_term_width("1337").is_err());
     }
 
     #[test]
     fn negative_value() {
+        terminal_size_wrapper.mock_safe(|| MockResult::Return((Width(42), Height(42))));
         assert!(is_fitting_term_width("-13").is_err());
     }
 
     #[test]
     fn string_value() {
+        terminal_size_wrapper.mock_safe(|| MockResult::Return((Width(42), Height(42))));
         assert!(is_fitting_term_width("not a number").is_err());
     }
 }
@@ -51,7 +65,7 @@ mod is_fitting_term_width {
 /// The last 2 lines are used for status reporting (seed/input) and space
 /// for ease of use
 pub(crate) fn is_fitting_term_height(val: &str) -> Result<(), String> {
-    let (Width(_), Height(term_height)) = terminal_size().unwrap();
+    let (Width(_), Height(term_height)) = terminal_size_wrapper();
     let term_height = term_height - 2;
     match val.parse::<u16>() {
         Ok(n) if n > 0 && n <= term_height => Ok(()),
@@ -66,24 +80,29 @@ pub(crate) fn is_fitting_term_height(val: &str) -> Result<(), String> {
 #[cfg(test)]
 mod is_fitting_term_height {
     use super::*;
+    use mocktopus::mocking::*;
 
     #[test]
     fn positive_value() {
+        terminal_size_wrapper.mock_safe(|| MockResult::Return((Width(42), Height(42))));
         assert!(is_fitting_term_height("13").is_ok());
     }
 
     #[test]
     fn value_too_large() {
+        terminal_size_wrapper.mock_safe(|| MockResult::Return((Width(42), Height(42))));
         assert!(is_fitting_term_height("1337").is_err());
     }
 
     #[test]
     fn negative_value() {
+        terminal_size_wrapper.mock_safe(|| MockResult::Return((Width(42), Height(42))));
         assert!(is_fitting_term_height("-13").is_err());
     }
 
     #[test]
     fn string_value() {
+        terminal_size_wrapper.mock_safe(|| MockResult::Return((Width(42), Height(42))));
         assert!(is_fitting_term_height("not a number").is_err());
     }
 }