public function testMatrixMultiplyByMatrix() { $matrix1 = new Matrix([[1, 2, 3], [4, 5, 6]]); $matrix2 = new Matrix([[7, 8], [9, 10], [11, 12]]); $product = [[58, 64], [139, 154]]; $this->assertEquals($product, $matrix1->multiply($matrix2)->toArray()); }