Add unit tests for transposition

src/card.rs

@@ -619,14 +619,97 @@ mod test {
     assert_eq!(result, expected);
   }
 
+  /// Test transposition on column 1
   #[test]
   fn transpose_vertical() {
-    todo!();
+    let left_shape = Card {
+      cells: OCTAGON,
+      ..Default::default()
+    };
+
+    // It's a small NW triangle.
+    let right_shape = Card {
+      #[rustfmt::skip]
+      cells: [
+        Cell::Filled, Cell::Empty, Cell::Empty,
+        Cell::SE, Cell::Empty, Cell::NW,
+        Cell::Empty, Cell::NW, Cell::Filled,
+      ],
+      ..Default::default()
+    };
+
+    let expected_left = Card {
+      #[rustfmt::skip]
+      cells: [
+        Cell::Filled, Cell::Filled, Cell::NE,
+        Cell::SE, Cell::Filled, Cell::Filled,
+        Cell::Empty, Cell::Filled, Cell::SE,
+      ],
+      ..Default::default()
+    };
+
+    let expected_right = Card {
+      #[rustfmt::skip]
+      cells: [
+        Cell::NW, Cell::Empty, Cell::Empty,
+        Cell::Filled, Cell::Empty, Cell::NW,
+        Cell::SW, Cell::NW, Cell::Filled,
+      ],
+      ..Default::default()
+    };
+
+    let (res_left, res_right) = left_shape.transpose(
+      right_shape,
+      TransposeSelection::Column(TransposeIndex::First),
+    );
+    assert_eq!(res_left, expected_left);
+    assert_eq!(res_right, expected_right);
   }
 
+  /// Test transposition on row 3
   #[test]
   fn transpose_horizontal() {
-    todo!();
+    let left_shape = Card {
+      cells: OCTAGON,
+      ..Default::default()
+    };
+
+    let right_shape = Card {
+      #[rustfmt::skip]
+      cells: [
+        Cell::Filled, Cell::Empty, Cell::Empty,
+        Cell::SE, Cell::Empty, Cell::NW,
+        Cell::Empty, Cell::NW, Cell::Filled,
+      ],
+      ..Default::default()
+    };
+
+    let expected_left = Card {
+      #[rustfmt::skip]
+      cells: [
+        Cell::NW, Cell::Filled, Cell::NE,
+        Cell::Filled, Cell::Filled, Cell::Filled,
+        Cell::Empty, Cell::NW, Cell::Filled,
+      ],
+      ..Default::default()
+    };
+
+    let expected_right = Card {
+      #[rustfmt::skip]
+      cells: [
+        Cell::Filled, Cell::Empty, Cell::Empty,
+        Cell::SE, Cell::Empty, Cell::NW,
+        Cell::SW, Cell::Filled, Cell::SE,
+      ],
+      ..Default::default()
+    };
+
+    let (res_left, res_right) = left_shape.transpose(
+      right_shape,
+      TransposeSelection::Row(TransposeIndex::Third),
+    );
+    assert_eq!(res_left, expected_left);
+    assert_eq!(res_right, expected_right);
   }
 
   #[test]