diff --git a/tools/runtest b/tools/runtest
index a3c9331..9368ce9 100755
--- a/tools/runtest
+++ b/tools/runtest
@@ -89,9 +89,17 @@ done
 # we must have found an input file
 if [ ! -f "$infile" ]; then usage; fi
 
-# set program to the .c file base name if not specified otherwise
 if [ -z "$program" ]; then
-    program=`basename "$infile" .c`
+    # try to autodetect the test program name based on the working directory
+    if [ "$(basename $PWD)" = "tests" ]; then
+        program="$(basename $(dirname $PWD))_test.exe.so"
+    elif [ -d "tests" ]; then
+        program="tests/$(basename $PWD)_test.exe.so"
+    fi
+    if [ ! -f "$program" ]; then
+        echo "Can't find the test program, use the -p argument to specify one" 2>&1
+        usage
+    fi
 fi
 
 # check/detect topobjdir