diff --git a/iwads/.gitignore b/iwads/.gitignore
new file mode 100644
index 000000000..4ac7e24d0
--- /dev/null
+++ b/iwads/.gitignore
@@ -0,0 +1,4 @@
+doom.wad
+doom2.wad
+plutonia.wad
+tnt.wad
diff --git a/makedepends b/makedepends
index 03c287ef7..f4812486c 100755
--- a/makedepends
+++ b/makedepends
@@ -2,6 +2,7 @@
 
 from glob import glob
 import os
+from os.path import exists, join
 import sys
 
 from common import *
@@ -13,6 +14,10 @@ for filename in glob("expected/**/*.txt", recursive=True):
     lmp_file = filename.replace("expected/", "demos/").replace(".txt", ".lmp")
     cfg = read_config(lmp_file)
 
+    iwad = cfg.get("iwad")
+    assert exists(join("iwads", iwad)), (
+        "IWAD file %r not found in iwads/ directory." % iwad)
+
     pwad = cfg.get("pwad")
     if pwad is not None:
         out_file = filename.replace("expected/", "output/")
diff --git a/testrunner b/testrunner
index 3f0356fc7..03cd74815 100755
--- a/testrunner
+++ b/testrunner
@@ -13,7 +13,8 @@ lmp_file, out_file = sys.argv[1:]
 cfg = read_config(lmp_file)
 
 args = [
-    source_port, "-iwad", cfg["iwad"],
+    source_port,
+    "-iwad", join("iwads", cfg["iwad"]),
     "-statdump", out_file,
     "-timedemo", lmp_file,
 ] + shlex.split(os.getenv("DOOMOPTS", ""))