public function testIsZeroAndIsNull() { $matrix = new Matrix(3, 3, 2); $sut = new Properties($matrix, 2); $this->assertTrue($sut->isZero()); $this->assertTrue($sut->isNull()); $matrix = new Matrix(3, 3, 2); $matrix->setPoint(1, 3, -5, 2); $sut = new Properties($matrix, 2); $this->assertFalse($sut->isZero()); $this->assertFalse($sut->isNull()); }