diff --git a/ChangeLog b/ChangeLog
index 566a7e56c..8b82580a8 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,12 @@
 2003-04-29  Alexandre DURET-LUTZ  <aduret@src.lip6.fr>
 
+	* src/ltltest/tostring.test: Simplify with set -e.  Move the
+	description of the test ...
+	* src/ltltest/tostring.cc: ... here, where it is actually coded.
+	* src/ltltest/lunabbrev.test, src/ltltest/tunabbrev.test, 
+	src/ltltest/nenoform.test,  src/ltltest/tunenoform.test: 
+	Simplify with set -e.
+
 	* configure.ac (AM_INIT_AUTOMAKE): Use nostdinc, to make
 	sure we always use paths relative to src/ in src/'s 
 	subdirectories.
diff --git a/src/ltltest/lunabbrev.test b/src/ltltest/lunabbrev.test
index 386dfd165..0f1a5fde8 100755
--- a/src/ltltest/lunabbrev.test
+++ b/src/ltltest/lunabbrev.test
@@ -4,32 +4,25 @@
 
 . ./defs || exit 1
 
-check()
-{
-  ./lunabbrev "$1" "$2" || exit 1
-}
+set -e
 
 # A few things that do not change
-check 'a' 'a'
-check '1' '1'
-check '0' '0'
-check 'G a ' ' G a'
-check 'a U b' 'a U b'
-check 'a & b' 'a & b'
-check 'a & b' 'b & a'
-check 'a & b & c' 'c & a & b'
-check 'a & b & c' 'b & c & a'
-check 'a & b & a' 'b & a & b'
-check 'a & b' 'b & a & b'
-check 'a & b' 'b & a & a'
-check 'a & b & (c |(f U g)| e)' 'b & a & a & (c | e |(f U g)| e | c) & b'
-
+./lunabbrev 'a' 'a'
+./lunabbrev '1' '1'
+./lunabbrev '0' '0'
+./lunabbrev 'G a ' ' G a'
+./lunabbrev 'a U b' 'a U b'
+./lunabbrev 'a & b' 'a & b'
+./lunabbrev 'a & b' 'b & a'
+./lunabbrev 'a & b & c' 'c & a & b'
+./lunabbrev 'a & b & c' 'b & c & a'
+./lunabbrev 'a & b & a' 'b & a & b'
+./lunabbrev 'a & b' 'b & a & b'
+./lunabbrev 'a & b' 'b & a & a'
+./lunabbrev 'a & b & (c |(f U g)| e)' 'b & a & a & (c | e |(f U g)| e | c) & b'
 # other formulae that do change
-check 'a ^ b' '(a & !b) | (!a & b)'
-check 'a ^ Xb' '(!Xb & a) | (!a & Xb) | (Xb & !a)'
-check 'GF a => F G(b)' '!GFa | F Gb'
-check '!a <-> Xb' '(Xb & !a) | (!!a & !Xb)'
-check '(a ^ b) | (b ^ c)' '(c & !b) | (!c & b) | (a & !b) | (!a & b)'
-
-# Success.
-:
\ No newline at end of file
+./lunabbrev 'a ^ b' '(a & !b) | (!a & b)'
+./lunabbrev 'a ^ Xb' '(!Xb & a) | (!a & Xb) | (Xb & !a)'
+./lunabbrev 'GF a => F G(b)' '!GFa | F Gb'
+./lunabbrev '!a <-> Xb' '(Xb & !a) | (!!a & !Xb)'
+./lunabbrev '(a ^ b) | (b ^ c)' '(c & !b) | (!c & b) | (a & !b) | (!a & b)'
diff --git a/src/ltltest/nenoform.test b/src/ltltest/nenoform.test
index 91cf388d6..224500b3c 100755
--- a/src/ltltest/nenoform.test
+++ b/src/ltltest/nenoform.test
@@ -4,46 +4,40 @@
 
 . ./defs || exit 1
 
-check()
-{
-  ./nenoform "$1" "$2" || exit 1
-}
+set -e
 
 # A few things that do not change
-check 'a' 'a'
-check '1' '1'
-check '0' '0'
-check '!a' '!a'
-check 'a U b' 'a U b'
-check 'a & b' 'a & b'
-check 'a & b' 'b & a'
-check 'a & !b & c' 'c & a & !b'
-check 'a & b & c' 'b & c & a'
-check 'Xa & b & Xa' 'b & Xa & b'
-check 'a & b' 'b & a & b'
-check 'a & !b' '!b & a & a'
-check 'a & b & (Xc |(f U !g)| e)' 'b & a & a & (Xc | e |(f U !g)| e | Xc) & b'
-check 'GFa => FGb' 'GFa => FGb'
+./nenoform 'a' 'a'
+./nenoform '1' '1'
+./nenoform '0' '0'
+./nenoform '!a' '!a'
+./nenoform 'a U b' 'a U b'
+./nenoform 'a & b' 'a & b'
+./nenoform 'a & b' 'b & a'
+./nenoform 'a & !b & c' 'c & a & !b'
+./nenoform 'a & b & c' 'b & c & a'
+./nenoform 'Xa & b & Xa' 'b & Xa & b'
+./nenoform 'a & b' 'b & a & b'
+./nenoform 'a & !b' '!b & a & a'
+./nenoform 'a & b & (Xc |(f U !g)| e)' 'b & a & a & (Xc | e |(f U !g)| e | Xc) & b'
+./nenoform 'GFa => FGb' 'GFa => FGb'
 
 # Basic rewritings
-check '!!a' 'a'
-check '!!!!!a' '!a'
-check '!Xa' 'X!a'
-check '!Fa' 'G!a'
-check '!Ga' 'F!a'
-check '!(a ^ b)' 'a <=> b'
-check '!(a <=> b)' '(((a) ^ (b)))'
-check '!(a => b)' 'a&!b'
-check '!(!a => !b)' '!a&b'
-check '!(a U b)' '!a R !b'
-check '!(a R b)' '!a U !b'
-check '!(!a R !b)' 'a U b'
-check '!(a & b & c & d & b)' '!a | !b | !c | !d'
-check '!(a | b | c | d)' '!a & !b & !c & !d'
+./nenoform '!!a' 'a'
+./nenoform '!!!!!a' '!a'
+./nenoform '!Xa' 'X!a'
+./nenoform '!Fa' 'G!a'
+./nenoform '!Ga' 'F!a'
+./nenoform '!(a ^ b)' 'a <=> b'
+./nenoform '!(a <=> b)' '(((a) ^ (b)))'
+./nenoform '!(a => b)' 'a&!b'
+./nenoform '!(!a => !b)' '!a&b'
+./nenoform '!(a U b)' '!a R !b'
+./nenoform '!(a R b)' '!a U !b'
+./nenoform '!(!a R !b)' 'a U b'
+./nenoform '!(a & b & c & d & b)' '!a | !b | !c | !d'
+./nenoform '!(a | b | c | d)' '!a & !b & !c & !d'
 
 # Nested rewritings
-check '!(a U (!b U ((a & b & c) R d)))' '!a R (b R ((!a | !b | !c) U !d))'
-check '!(GF a => FG b)' 'GFa & GF!b'
-
-# Success.
-:
\ No newline at end of file
+./nenoform '!(a U (!b U ((a & b & c) R d)))' '!a R (b R ((!a | !b | !c) U !d))'
+./nenoform '!(GF a => FG b)' 'GFa & GF!b'
diff --git a/src/ltltest/tostring.cc b/src/ltltest/tostring.cc
index 66cb29a1d..3a2bb9217 100644
--- a/src/ltltest/tostring.cc
+++ b/src/ltltest/tostring.cc
@@ -16,13 +16,16 @@ main(int argc, char **argv)
 {
   if (argc != 2)
     syntax(argv[0]);
-  
+
   spot::ltl::parse_error_list p1;
   spot::ltl::formula* f1 = spot::ltl::parse(argv[1], p1);
 
   if (spot::ltl::format_parse_errors(std::cerr, argv[1], p1))
     return 2;
 
+  // The string generated from an abstract tree should be parsable
+  // again.
+
   std::ostringstream os;
   spot::ltl::to_string(*f1, os);
   std::cout << os.str() << std::endl;
@@ -32,14 +35,18 @@ main(int argc, char **argv)
   if (spot::ltl::format_parse_errors(std::cerr, os.str(), p1))
     return 2;
 
+  // This second abstract tree should be equal to the first.
+
+  if (! equals(f1, f2))
+    return 1;
+
+  // It should also map to the same string.
+
   std::ostringstream os2;
   spot::ltl::to_string(*f2, os2);
   std::cout << os2.str() << std::endl;
 
   if (os2.str() != os.str())
     return 1;
-
-  if (! equals(f1, f2))
-    return 1;
 }
  
diff --git a/src/ltltest/tostring.test b/src/ltltest/tostring.test
index 04c7a3015..9579b63a5 100755
--- a/src/ltltest/tostring.test
+++ b/src/ltltest/tostring.test
@@ -1,28 +1,24 @@
 #! /bin/sh
 
-# Check that spot::ltl::tostring is correct: after to parse we get the
-# string of the abstract syntax tree and xe parse it again to apply spot::ltl::tostring one more times.
+# Check for spot::ltl::tostring.
 
 . ./defs || exit 1
 
-check()
-{
-  ./tostring "$1" || exit 1
-}
+set -e 
+
+./tostring 'a'
+./tostring '1'
+./tostring '0'
+./tostring 'a => b'
+./tostring 'G a '
+./tostring 'a U b'
+./tostring 'a & b'
+./tostring 'a & b & c'
+./tostring 'b & a & b'
+./tostring 'b & a & a'
+./tostring 'a & b & (c |(f U g)| e)'
+./tostring 'b & a & a & (c | e |(f U g)| e | c) & b'
+./tostring 'a <=> b'
+./tostring 'a & b & (c |(f U g)| e)'
+./tostring 'b & a & a & (c | e |(g U g)| e | c) & b'
 
-check 'a'
-check '1'
-check '0'
-check 'a => b'
-check 'G a '
-check 'a U b'
-check 'a & b'
-check 'a & b & c'
-check 'b & a & b'
-check 'b & a & a'
-check 'a & b & (c |(f U g)| e)'
-check 'b & a & a & (c | e |(f U g)| e | c) & b'
-check 'a <=> b'
-check 'a & b & (c |(f U g)| e)'
-check 'b & a & a & (c | e |(g U g)| e | c) & b'
-:
diff --git a/src/ltltest/tunabbrev.test b/src/ltltest/tunabbrev.test
index 80ae8c56b..2321f9ddd 100755
--- a/src/ltltest/tunabbrev.test
+++ b/src/ltltest/tunabbrev.test
@@ -4,36 +4,30 @@
 
 . ./defs || exit 1
 
-check()
-{
-  ./tunabbrev "$1" "$2" || exit 1
-}
+set -e
 
 # A few things that do not change
-check 'a' 'a'
-check '1' '1'
-check '0' '0'
-check 'a U b' 'a U b'
-check 'a & b' 'a & b'
-check 'a & b' 'b & a'
-check 'a & b & c' 'c & a & b'
-check 'a & b & c' 'b & c & a'
-check 'a & b & a' 'b & a & b'
-check 'a & b' 'b & a & b'
-check 'a & b' 'b & a & a'
-check 'a & b & (c |(f U g)| e)' 'b & a & a & (c | e |(f U g)| e | c) & b'
+./tunabbrev 'a' 'a'
+./tunabbrev '1' '1'
+./tunabbrev '0' '0'
+./tunabbrev 'a U b' 'a U b'
+./tunabbrev 'a & b' 'a & b'
+./tunabbrev 'a & b' 'b & a'
+./tunabbrev 'a & b & c' 'c & a & b'
+./tunabbrev 'a & b & c' 'b & c & a'
+./tunabbrev 'a & b & a' 'b & a & b'
+./tunabbrev 'a & b' 'b & a & b'
+./tunabbrev 'a & b' 'b & a & a'
+./tunabbrev 'a & b & (c |(f U g)| e)' 'b & a & a & (c | e |(f U g)| e | c) & b'
 
 # same as in lunabbrev.test:
-check 'a ^ b' '(a & !b) | (!a & b)'
-check 'a ^ Xb' '(!Xb & a) | (!a & Xb) | (Xb & !a)'
-check '!a <-> Xb' '(Xb & !a) | (!!a & !Xb)'
-check '(a ^ b) | (b ^ c)' '(c & !b) | (!c & b) | (a & !b) | (!a & b)'
+./tunabbrev 'a ^ b' '(a & !b) | (!a & b)'
+./tunabbrev 'a ^ Xb' '(!Xb & a) | (!a & Xb) | (Xb & !a)'
+./tunabbrev '!a <-> Xb' '(Xb & !a) | (!!a & !Xb)'
+./tunabbrev '(a ^ b) | (b ^ c)' '(c & !b) | (!c & b) | (a & !b) | (!a & b)'
 
 # LTL unabbreviations:
-check 'G a ' 'false R a'
-check 'GF a => F G(b)' '!(false R (true U a)) | (true U (false V b))'
-check 'GGGGa' 'false V (false V (false V (false V a)))'
-check 'FFFfalse' 'true U ((true) U (true U (false)))'
-
-# Success.
-:
\ No newline at end of file
+./tunabbrev 'G a ' 'false R a'
+./tunabbrev 'GF a => F G(b)' '!(false R (true U a)) | (true U (false V b))'
+./tunabbrev 'GGGGa' 'false V (false V (false V (false V a)))'
+./tunabbrev 'FFFfalse' 'true U ((true) U (true U (false)))'
diff --git a/src/ltltest/tunenoform.test b/src/ltltest/tunenoform.test
index 0eba7111e..c131800b9 100755
--- a/src/ltltest/tunenoform.test
+++ b/src/ltltest/tunenoform.test
@@ -4,18 +4,12 @@
 
 . ./defs || exit 1
 
-check()
-{
-  ./tunenoform "$1" "$2" || exit 1
-}
+set -e
 
-check '!(a ^ b)' '(a|!b) & (!a|b)'
-check '!(a <=> b)' '(a|b) & (!a|!b)'
-check '!(a => b)' 'a&!b'
-check '!(!a => !b)' '!a&b'
-check '!Fa' 'false R !a'
-check '!G!a' 'true U a'
-check '!(GF a => FG b)' '(0 R (1 U a)) & (0 R (1 U !b))'
-
-# Success.
-:
\ No newline at end of file
+./tunenoform '!(a ^ b)' '(a|!b) & (!a|b)'
+./tunenoform '!(a <=> b)' '(a|b) & (!a|!b)'
+./tunenoform '!(a => b)' 'a&!b'
+./tunenoform '!(!a => !b)' '!a&b'
+./tunenoform '!Fa' 'false R !a'
+./tunenoform '!G!a' 'true U a'
+./tunenoform '!(GF a => FG b)' '(0 R (1 U a)) & (0 R (1 U !b))'