The test is like this:

Assert.AreEqual("2000 103 123 4444 99", WeightSort.orderWeight("103 123 4444 99 2000"));
//                expected value                                    input value

2000 is at the beginning, not at the end, in the expected result. In the input value they can be at any order.

(manual notification, see above)

it checks that no pairs of queens are on the same diagonals (here, it's enough because no two queens can be on the same horizontal or vertical lines, considering how I generate the different possibilities)

You are right that when initial queen is given as c3, then c3 should be in the answer.

In the description, 'c3' is an example of an input, and 'd8,a7,e6,h5,b4,g3,c2,f1' is an eample of some output, not related to the example 'c3'. But this is a valuable remark, the example probably could be clarified in this matter.