diff --git a/src/matrix/mat.rs b/src/matrix/mat.rs
index ec61e66..f748ced 100644
--- a/src/matrix/mat.rs
+++ b/src/matrix/mat.rs
@@ -621,7 +621,242 @@ pub type StringMatrix = Matrix<String>;
 mod tests {
     use crate::matrix::BoolOps;
 
-    use super::{BoolMatrix, FloatMatrix, Matrix, StringMatrix};
+    use super::*; // Import items from outer scope
+
+    // Helper to create a 2x2 f64 matrix easily
+    fn make_f64_matrix(a: f64, b: f64, c: f64, d: f64) -> FloatMatrix {
+        Matrix::from_cols(vec![vec![a, c], vec![b, d]])
+    }
+
+    // Helper to create a 2x2 bool matrix easily
+    fn make_bool_matrix(a: bool, b: bool, c: bool, d: bool) -> BoolMatrix {
+        Matrix::from_cols(vec![vec![a, c], vec![b, d]])
+    }
+
+    // --- Arithmetic Tests ---
+
+    #[test]
+    fn test_add_f64() {
+        let m1 = make_f64_matrix(1.0, 2.0, 3.0, 4.0);
+        let m2 = make_f64_matrix(5.0, 6.0, 7.0, 8.0);
+        let expected = make_f64_matrix(6.0, 8.0, 10.0, 12.0);
+
+        assert_eq!(m1.clone() + m2.clone(), expected, "M + M");
+        assert_eq!(m1.clone() + &m2, expected, "M + &M");
+        assert_eq!(&m1 + m2.clone(), expected, "&M + M");
+        assert_eq!(&m1 + &m2, expected, "&M + &M");
+    }
+
+    #[test]
+    fn test_add_scalar_f64() {
+        let m1 = make_f64_matrix(1.0, 2.0, 3.0, 4.0);
+        let scalar = 10.0;
+        let expected = make_f64_matrix(11.0, 12.0, 13.0, 14.0);
+
+        assert_eq!(m1.clone() + scalar, expected, "M + S");
+        assert_eq!(&m1 + scalar, expected, "&M + S");
+    }
+
+    #[test]
+    fn test_sub_f64() {
+        let m1 = make_f64_matrix(10.0, 20.0, 30.0, 40.0);
+        let m2 = make_f64_matrix(1.0, 2.0, 3.0, 4.0);
+        let expected = make_f64_matrix(9.0, 18.0, 27.0, 36.0);
+
+        assert_eq!(m1.clone() - m2.clone(), expected, "M - M");
+        assert_eq!(m1.clone() - &m2, expected, "M - &M");
+        assert_eq!(&m1 - m2.clone(), expected, "&M - M");
+        assert_eq!(&m1 - &m2, expected, "&M - &M");
+    }
+
+    #[test]
+    fn test_sub_scalar_f64() {
+        let m1 = make_f64_matrix(11.0, 12.0, 13.0, 14.0);
+        let scalar = 10.0;
+        let expected = make_f64_matrix(1.0, 2.0, 3.0, 4.0);
+
+        assert_eq!(m1.clone() - scalar, expected, "M - S");
+        assert_eq!(&m1 - scalar, expected, "&M - S");
+    }
+
+    #[test]
+    fn test_mul_f64() {
+        // Element-wise
+        let m1 = make_f64_matrix(1.0, 2.0, 3.0, 4.0);
+        let m2 = make_f64_matrix(5.0, 6.0, 7.0, 8.0);
+        let expected = make_f64_matrix(5.0, 12.0, 21.0, 32.0);
+
+        assert_eq!(m1.clone() * m2.clone(), expected, "M * M");
+        assert_eq!(m1.clone() * &m2, expected, "M * &M");
+        assert_eq!(&m1 * m2.clone(), expected, "&M * M");
+        assert_eq!(&m1 * &m2, expected, "&M * &M");
+    }
+
+    #[test]
+    fn test_mul_scalar_f64() {
+        let m1 = make_f64_matrix(1.0, 2.0, 3.0, 4.0);
+        let scalar = 3.0;
+        let expected = make_f64_matrix(3.0, 6.0, 9.0, 12.0);
+
+        assert_eq!(m1.clone() * scalar, expected, "M * S");
+        assert_eq!(&m1 * scalar, expected, "&M * S");
+    }
+
+    #[test]
+    fn test_div_f64() {
+        // Element-wise
+        let m1 = make_f64_matrix(10.0, 20.0, 30.0, 40.0);
+        let m2 = make_f64_matrix(2.0, 5.0, 6.0, 8.0);
+        let expected = make_f64_matrix(5.0, 4.0, 5.0, 5.0);
+
+        assert_eq!(m1.clone() / m2.clone(), expected, "M / M");
+        assert_eq!(m1.clone() / &m2, expected, "M / &M");
+        assert_eq!(&m1 / m2.clone(), expected, "&M / M");
+        assert_eq!(&m1 / &m2, expected, "&M / &M");
+    }
+
+    #[test]
+    fn test_div_scalar_f64() {
+        let m1 = make_f64_matrix(10.0, 20.0, 30.0, 40.0);
+        let scalar = 10.0;
+        let expected = make_f64_matrix(1.0, 2.0, 3.0, 4.0);
+
+        assert_eq!(m1.clone() / scalar, expected, "M / S");
+        assert_eq!(&m1 / scalar, expected, "&M / S");
+    }
+
+    #[test]
+    fn test_chained_ops_f64() {
+        let m = make_f64_matrix(1.0, 2.0, 3.0, 4.0);
+        let result = (((m.clone() + 1.0) * 2.0) - 4.0) / 2.0;
+        // Expected:
+        // m+1 = [2, 3], [4, 5]
+        // *2  = [4, 6], [8, 10]
+        // -4  = [0, 2], [4, 6]
+        // /2  = [0, 1], [2, 3]
+        let expected = make_f64_matrix(0.0, 1.0, 2.0, 3.0);
+        assert_eq!(result, expected);
+    }
+
+    // --- Boolean Logic Tests ---
+
+    #[test]
+    fn test_bitand_bool() {
+        let m1 = make_bool_matrix(true, false, true, false);
+        let m2 = make_bool_matrix(true, true, false, false);
+        let expected = make_bool_matrix(true, false, false, false);
+
+        assert_eq!(m1.clone() & m2.clone(), expected, "M & M");
+        assert_eq!(m1.clone() & &m2, expected, "M & &M");
+        assert_eq!(&m1 & m2.clone(), expected, "&M & M");
+        assert_eq!(&m1 & &m2, expected, "&M & &M");
+    }
+
+    #[test]
+    fn test_bitor_bool() {
+        let m1 = make_bool_matrix(true, false, true, false);
+        let m2 = make_bool_matrix(true, true, false, false);
+        let expected = make_bool_matrix(true, true, true, false);
+
+        assert_eq!(m1.clone() | m2.clone(), expected, "M | M");
+        assert_eq!(m1.clone() | &m2, expected, "M | &M");
+        assert_eq!(&m1 | m2.clone(), expected, "&M | M");
+        assert_eq!(&m1 | &m2, expected, "&M | &M");
+    }
+
+    #[test]
+    fn test_bitxor_bool() {
+        let m1 = make_bool_matrix(true, false, true, false);
+        let m2 = make_bool_matrix(true, true, false, false);
+        let expected = make_bool_matrix(false, true, true, false);
+
+        assert_eq!(m1.clone() ^ m2.clone(), expected, "M ^ M");
+        assert_eq!(m1.clone() ^ &m2, expected, "M ^ &M");
+        assert_eq!(&m1 ^ m2.clone(), expected, "&M ^ M");
+        assert_eq!(&m1 ^ &m2, expected, "&M ^ &M");
+    }
+
+    #[test]
+    fn test_not_bool() {
+        let m = make_bool_matrix(true, false, true, false);
+        let expected = make_bool_matrix(false, true, false, true);
+
+        assert_eq!(!m.clone(), expected, "!M (consuming)");
+        assert_eq!(!&m, expected, "!&M (borrowing)");
+
+        // Check original is unchanged when using !&M
+        let original = make_bool_matrix(true, false, true, false);
+        let _negated_ref = !&original;
+        assert_eq!(original, make_bool_matrix(true, false, true, false));
+    }
+
+    // --- Comparison Tests ---
+    #[test]
+    fn test_comparison_eq_elem() {
+        let m1 = make_f64_matrix(1.0, 2.0, 3.0, 4.0);
+        let m2 = make_f64_matrix(1.0, 0.0, 3.0, 5.0);
+        let s = 3.0;
+        let expected_m = make_bool_matrix(true, false, true, false);
+        let expected_s = make_bool_matrix(false, false, true, false);
+
+        assert_eq!(m1.eq_elem(m2), expected_m, "eq_elem matrix");
+        assert_eq!(m1.eq_elem(s), expected_s, "eq_elem scalar");
+    }
+
+    #[test]
+    fn test_comparison_gt_elem() {
+        let m1 = make_f64_matrix(1.0, 2.0, 3.0, 4.0);
+        let m2 = make_f64_matrix(0.0, 3.0, 3.0, 5.0);
+        let s = 2.5;
+        let expected_m = make_bool_matrix(true, false, false, false);
+        let expected_s = make_bool_matrix(false, false, true, true);
+
+        assert_eq!(m1.gt_elem(m2), expected_m, "gt_elem matrix");
+        assert_eq!(m1.gt_elem(s), expected_s, "gt_elem scalar");
+    }
+
+    // Add more comparison tests (lt, le, ge, ne) if desired...
+
+    // --- Basic Method Tests ---
+    #[test]
+    fn test_indexing() {
+        let m = make_f64_matrix(1.0, 2.0, 3.0, 4.0);
+        assert_eq!(m[(0, 0)], 1.0);
+        assert_eq!(m[(0, 1)], 2.0);
+        assert_eq!(m[(1, 0)], 3.0);
+        assert_eq!(m[(1, 1)], 4.0);
+        assert_eq!(*m.get(1, 0), 3.0); // Test get() too
+    }
+
+    #[test]
+    #[should_panic]
+    fn test_index_out_of_bounds_row() {
+        let m = make_f64_matrix(1.0, 2.0, 3.0, 4.0);
+        let _ = m[(2, 0)]; // Row 2 is out of bounds
+    }
+
+    #[test]
+    #[should_panic]
+    fn test_index_out_of_bounds_col() {
+        let m = make_f64_matrix(1.0, 2.0, 3.0, 4.0);
+        let _ = m[(0, 2)]; // Col 2 is out of bounds
+    }
+
+    #[test]
+    fn test_dimensions() {
+        let m = make_f64_matrix(1.0, 2.0, 3.0, 4.0);
+        assert_eq!(m.rows(), 2);
+        assert_eq!(m.cols(), 2);
+    }
+
+    #[test]
+    fn test_from_vec() {
+        let data = vec![1.0, 3.0, 2.0, 4.0]; // Column major: [col0_row0, col0_row1, col1_row0, col1_row1]
+        let m = Matrix::from_vec(data, 2, 2);
+        let expected = make_f64_matrix(1.0, 2.0, 3.0, 4.0);
+        assert_eq!(m, expected);
+        assert_eq!(m.to_vec(), vec![1.0, 3.0, 2.0, 4.0]);
+    }
 
     // Helper function to create a basic Matrix for testing
     fn static_test_matrix() -> Matrix<i32> {