public void test_Envelope()
{
//create a new collection
MultiLineString multiLS = CreateMLS();
//put the envelope into a geometry
Geometry env = multiLS.GetEnvelope() as Geometry;
//make sure there is something in the envelope
Assertion.AssertEquals("Envelope-1: ", false, env.IsEmpty());
Coordinates coords = env.GetCoordinates();
//check the first set of coordinates (minX, minY)
Assertion.AssertEquals("Envelope-2: ", 0.0, coords[0].X);
Assertion.AssertEquals("Envelope-3: ", 5.0, coords[0].Y);
//check the second set of coordinates (maxX, minY)
Assertion.AssertEquals("Envelope-4: ", 18.0, coords[1].X);
Assertion.AssertEquals("Envelope-5: ", 5.0, coords[1].Y);
//check the third set of coordinates (maxX, maxY)
Assertion.AssertEquals("Envelope-6: ", 18.0, coords[2].X);
Assertion.AssertEquals("Envelope-7: ", 23.0, coords[2].Y);
//check the forth set of coordinates (minX, maxY)
Assertion.AssertEquals("Envelope-8: ", 0.0, coords[3].X);
Assertion.AssertEquals("Envelope-9: ", 23.0, coords[3].Y);
//check the fifth set of coordinates (minX, minY)
Assertion.AssertEquals("Envelope-10: ", 0.0, coords[4].X);
Assertion.AssertEquals("Envelope-11: ", 5.0, coords[4].Y);
//create a null collection
GeometryFactory gf = new GeometryFactory(_precMod, _sRID);
multiLS = gf.CreateMultiLineString(null);
//put the envelope into a geometry
env = multiLS.GetEnvelope() as Geometry;
//make sure there is something in the envelope
Assertion.AssertEquals("Envelope-12: ", true, env.IsEmpty());
}