@Test
public void noContours() {

    // Coverage with values in range [0, 10]
    GridCoverage2D cov = createVerticalGradient(10, 10, null, 0, 10);
    // Run process asking for contours at level = 20
    SimpleFeatureCollection fc = process.execute(cov, 0, new double[20], null, null, null, null, null);
    assertNotNull(fc);
    assertTrue(fc.isEmpty());
}