diff --git a/tools/runtest b/tools/runtest
index a3c9331..b21aa96 100755
--- a/tools/runtest
+++ b/tools/runtest
@@ -89,9 +89,22 @@ 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`
+    workingpath=`pwd`
+    workingbasename=`basename "$workingpath"`
+    parentpath=`dirname "$workingpath"`
+    parentbasename=`basename "$parentpath"`
+
+    # try to autodetect the test program name based on the working directory
+    if [ "$workingbasename" = "tests" ]; then
+        program="${parentbasename}_test.exe.so"
+    elif [ -d "tests" ]; then
+        program="tests/${workingbasename}_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