Fix serde tests without default features

Authored-by: James McCoy <jamessan@jamessan.com>

.github/workflows/ci.yml

@@ -17,6 +17,8 @@ jobs:
       - uses: actions/checkout@v3
       - name: Stable
         run: cargo test
+      - name: Stable (no default features)
+        run: cargo test -p alacritty_terminal --no-default-features
       - name: Oldstable
         run: |
           rustup default 1.70.0

alacritty_terminal/src/term/mod.rs

@@ -2710,6 +2710,7 @@ mod tests {
     /// This test is in the term module as opposed to the grid since we want to
     /// test this property with a T=Cell.
     #[test]
+    #[cfg(feature = "serde")]
     fn grid_serde() {
         let grid: Grid<Cell> = Grid::new(24, 80, 0);
         let serialized = serde_json::to_string(&grid).expect("ser");

alacritty_terminal/tests/ref.rs

@@ -1,3 +1,4 @@
+#![cfg(feature = "serde")]
 use serde::Deserialize;
 use serde_json as json;