[add] tests for matrix rotations and vector cross products.

Author: vmarcella

crates/lambda-rs/src/math/matrix.rs

@@ -397,6 +397,7 @@ mod tests {
 
   use super::{
     filled_matrix,
+    identity_matrix,
     perspective_matrix,
     rotate_matrix,
     submatrix,
@@ -542,4 +543,30 @@ mod tests {
       }
     }
   }
+
+  /// Verify that `rotate_matrix` returns `InvalidRotationAxis` when a non-unit
+  /// axis vector is provided.
+  #[test]
+  fn rotate_matrix_fails_for_invalid_axis() {
+    let matrix: [[f32; 4]; 4] = identity_matrix(4, 4);
+    let result = rotate_matrix(matrix, [1.0, 1.0, 0.0], 0.25);
+    assert_eq!(
+      result,
+      Err(MathError::InvalidRotationAxis {
+        axis: [1.0, 1.0, 0.0]
+      })
+    );
+  }
+
+  /// Verify that `rotate_matrix` returns `InvalidRotationMatrixSize` when a
+  /// non-4x4 matrix is provided.
+  #[test]
+  fn rotate_matrix_fails_for_non_4x4_matrix() {
+    let matrix: [[f32; 3]; 3] = identity_matrix(3, 3);
+    let result = rotate_matrix(matrix, [0.0, 1.0, 0.0], 0.25);
+    assert_eq!(
+      result,
+      Err(MathError::InvalidRotationMatrixSize { rows: 3, cols: 3 })
+    );
+  }
 }

crates/lambda-rs/src/math/vector.rs

@@ -215,6 +215,20 @@ mod tests {
     assert_eq!(result, Err(MathError::CrossProductDimension { actual: 2 }));
   }
 
+  /// Verify that `cross` returns `MismatchedVectorDimensions` when vectors of
+  /// different dimensions are provided.
+  #[test]
+  fn cross_product_fails_for_mismatched_dimensions() {
+    let a: Vec<f32> = vec![1.0, 2.0];
+    let b: Vec<f32> = vec![4.0, 5.0, 6.0];
+
+    let result = a.cross(&b);
+    assert_eq!(
+      result,
+      Err(MathError::MismatchedVectorDimensions { left: 2, right: 3 })
+    );
+  }
+
   #[test]
   fn length() {
     let a = [1.0, 2.0, 3.0];