java - How to give null value to a parameter when using @FileParameters of JUnitParams -

i try use fileparameters annotation of junitparamsrunner. cannot give null variable. code , test file below.

@runwith(junitparamsrunner.class) public class passwordcheckerfileparameterizedtest {       @test     @fileparameters("src/test/resources/testscenarios.csv")     public void checkpasswordisvalid_checkmultiplecase(string password,boolean expectedresult){         passwordchecker passwordchecker = new passwordchecker();         assertequals(expectedresult,passwordchecker.checkpasswordisvalid(password));     } } 

testscenarios.csv

,false sd1.,false ssfdsdfsdf234.,false sewerwer234.,false ssfdsdfsdsdfsdf.,false ssfdsdfsdsdfsdf3234,false ssfdsdfsdsdfsdf23.,true 

this not work default since fileparameters uses identitymapper map lines in file parameters , works if used @parameters({"aaa,bbb", "ccc,ddd"} syntax in cannot provide null value - writing null give string saying "null".

you can provide own mapper means of fileparameters#mapper. has return mapped object[][] (same format if used method parameter provider @parameters(method = ...)). need decide in way you'll mark null in file.

a sample mapper treats string "xxx" null marker this:

public class xxxtonullmapper implements datamapper {     @override     public object[] map(reader reader) {         return new bufferedreader(reader).lines()                 .map(line -> line.split(","))                 .map(columns ->                         stream.of(columns)                                 .map(column -> column.equals("xxx") ? null : column)                                 .collect(collectors.tolist()).toarray()                 )                 .collect(collectors.tolist()).toarray();     } } 

usage:

@test @fileparameters(         value = "/test.csv",         mapper = xxxtonullmapper.class ) public void xxxisnullfileparameters(string a, string b) {     system.out.println("params are: " + + " (is null? " + (a == null) + "), " + b + " (is null? " + (b == null) + ")"); } 

/test.csv:

aaa,bbb aaa,xxx 

prints

params are: aaa (is null? false), bbb (is null? false) params are: aaa (is null? false), null (is null? true)