diff --git a/tests/sanity/80columns.test b/tests/sanity/80columns.test
index cfab94180..c1d297843 100755
--- a/tests/sanity/80columns.test
+++ b/tests/sanity/80columns.test
@@ -1,6 +1,6 @@
 #! /bin/sh
 # -*- coding: utf-8 -*-
-# Copyright (C) 2012 Laboratoire de Recherche et Développement de
+# Copyright (C) 2012, 2016 Laboratoire de Recherche et Développement de
 # l'Epita (LRDE).
 # Copyright (C) 2004, 2005 Laboratoire d'Informatique de Paris 6
 # (LIP6), département Systèmes Répartis Coopératifs (SRC), Université
@@ -25,7 +25,7 @@
 
 set -e
 
-rm -f failures
+rm -f failures.80
 
 LANG=en_US.UTF-8
 export LANG
@@ -55,15 +55,15 @@ for dir in "${srcdir-.}/../../spot" "${srcdir-.}/.."; do
 	   grep 'generated by flex' "$file" >/dev/null ; then
 	  :
 	else
-	  echo "$file" >>failures
+	  echo "$file" >>failures.80
 	fi
      fi
   done
 done
 
-if test -f failures; then
+if test -f failures.80; then
    echo "The following files contain lines with more than 80 characters:"
-   cat failures
-   rm failures
+   cat failures.80
+   rm failures.80
    exit 1;
 fi
diff --git a/tests/sanity/includes.test b/tests/sanity/includes.test
index efd74505f..a37e1b3d8 100755
--- a/tests/sanity/includes.test
+++ b/tests/sanity/includes.test
@@ -25,7 +25,7 @@
 
 set -e
 
-rm -f failures
+rm -f failures.inc
 
 
 INCDIR=${srcdir-.}/../../spot
@@ -45,15 +45,15 @@ for file in `find "$INCDIR" \( -name "${1-*}.hh" \
    else
      echo "Missing, or incorrect include guard." >&2
      echo "FAIL: $file"
-     echo "  $file" >> failures
+     echo "  $file" >> failures.inc
      continue
    fi
    echo "PASS: $file"
 done
 
-if test -f failures; then
+if test -f failures.inc; then
    echo "Failed files:"
-   cat failures
-   rm failures
+   cat failures.inc
+   rm failures.inc
    exit 1;
 fi
diff --git a/tests/sanity/private.test b/tests/sanity/private.test
index ba0d658f9..8e10605de 100755
--- a/tests/sanity/private.test
+++ b/tests/sanity/private.test
@@ -25,7 +25,7 @@
 
 set -e
 
-rm -f failures
+rm -f failures.private
 
 
 INCDIR=${srcdir-.}/../../spot
@@ -41,15 +41,15 @@ for file in `find "$INCDIR" \( -name "${1-*}.hh" \
 	:
       elif test -f "$INCDIR/${file%.*}.cc"; then
 	echo "FAIL: $file -- no exported symbol, should this file be private?"
-	echo "  $file" >> failures
+	echo "  $file" >> failures.private
       fi
       ;;
   esac
 done
 
-if test -f failures; then
+if test -f failures.private; then
    echo "Failed files:"
-   cat failures
-   rm failures
+   cat failures.private
+   rm failures.private
    exit 1
 fi
diff --git a/tests/sanity/style.test b/tests/sanity/style.test
index 5bd975f37..7ca9a2a1d 100755
--- a/tests/sanity/style.test
+++ b/tests/sanity/style.test
@@ -32,7 +32,7 @@ diag()
   echo ============================================================
 }
 
-rm -f failures
+rm -f failures.style
 
 GREP=grep
 
@@ -324,7 +324,7 @@ for dir in "$TOP/spot" "$TOP/bin" "$TOP/tests"; do
     esac
 
 
-    $fail && echo "$file" >>failures
+    $fail && echo "$file" >>failures.style
 
   done || : # Make sure sh does not abort when read exits with false.
 done
@@ -346,14 +346,14 @@ for dir in "${INCDIR-..}" "${INCDIR-..}/../bin" "${INCDIR-..}/../tests"; do
     $GREP '\.libs/' $tmp &&
 	diag "Don't reference files in .libs/, use Libtool instead."
 
-    $fail && echo "$file" >>failures
+    $fail && echo "$file" >>failures.style
   done || : # Make sure sh does not abort when read exits with false.
 done
 
-if test -f failures; then
+if test -f failures.style; then
    echo "The following files contain style errors:"
-   cat failures
-   rm failures
+   cat failures.style
+   rm failures.style
    exit 1;
 fi