TEST(Matrix, ColSwap) { MatrixQ A = {{1, 2, 3}, {4, 5, 6}, {7, 8, 9}}; MatrixQ B = {{2, 1, 3}, {5, 4, 6}, {8, 7, 9}}; EXPECT_EQ(B, A.col_swap(0, 1)); MatrixQ C = A; EXPECT_EQ(C, A.col_swap(0, 0)); }