c# - How do you Unit TEst code which uses String.IsNullOrEmpty? -

do write 2 unit tests? 1 value being null , 1 value being string.empty? similar string.isnullorwhitespace()?

typically i'd use nunit test cases test these permutations. they'll give coverage of 3 different checks without duplicating test code.

for example:

[testcase("")] [testcase(null)] public class sometest(string stringvalue) {    assert.throws<argumentexception>(()=> checkifnullorempty(stringvalue)); }  public void checkifnullorempty(string val) {    if(string.isnullorempty(val))    {        throw new argumentexception();    } }