diff --git a/koch.nim b/koch.nim
index f7c0ae204d..e8b08c5d2c 100644
--- a/koch.nim
+++ b/koch.nim
@@ -336,10 +336,11 @@ template `|`(a, b): expr = (if a.len > 0: a else: b)
 proc tests(args: string) =
   # we compile the tester with taintMode:on to have a basic
   # taint mode test :-)
-  exec "nim cc --taintMode:on tests/testament/tester"
+  let nimexe = findNim()
+  exec nimexe & " cc --taintMode:on tests/testament/tester"
   # Since tests take a long time (on my machine), and we want to defy Murhpys
   # law - lets make sure the compiler really is freshly compiled!
-  exec "nim c --lib:lib -d:release --opt:speed compiler/nim.nim"
+  exec nimexe & " c --lib:lib -d:release --opt:speed compiler/nim.nim"
   let tester = quoteShell(getCurrentDir() / "tests/testament/tester".exe)
   let success = tryExec tester & " " & (args|"all")
   if not existsEnv("TRAVIS") and not existsEnv("APPVEYOR"):