Trying to use Dustmite

[Nordlöw via Digitalmars-d-learn]

I'm trying to figure out how to use DustMite.

I have a file `tester.d` in a clean sub-directory `src` containing

void err(int x)
{
    assert(x > 0);
}

auto inc(int x)
{
    return x + 1;
}

void main(string[] args)
{
    auto y = inc(42);
    err(10);
    err(-10);
}


I want to reduce with respect to AssertError thrown in the 
function `err`. BUt when I call

    dustmite src 'dmd tester && ./tester | grep -qF "Assertion 
failure"'

I doesn't progress but instead I get

Loading src/tester.d
None => No
object.Exception@dustmite.d(270): Initial test fails (try using 
--no-redirect for details)
----------------
??:? _Dmain [0x5c6be8]
??:? 
_D2rt6dmain211_d_run_mainUiPPaPUAAaZiZ6runAllMFZ9__lambda1MFZv 
[0x62544e]
??:? void rt.dmain2._d_run_main(int, char**, extern (C) int 
function(char[][])*).tryExec(scope void delegate()) [0x625398]
??:? void rt.dmain2._d_run_main(int, char**, extern (C) int 
function(char[][])*).runAll() [0x62540a]
??:? void rt.dmain2._d_run_main(int, char**, extern (C) int 
function(char[][])*).tryExec(scope void delegate()) [0x625398]
??:? _d_run_main [0x625309]
??:? main [0x61732d]
??:? __libc_start_main [0xb429f82f]

What am doing wrong?