Add n-ary version of `two_normalisers` to testsuite lib

This is more readable than nesting `two_normalisers()`-invocations

testsuite/driver/testlib.py

@@ -506,8 +506,29 @@ def _normalise_errmsg_fun( name, opts, f ):
     opts.extra_errmsg_normaliser = f
 
 def two_normalisers(f, g):
+    """
+    See also `join_normalisers` for a n-ary version of `two_normalisers`
+    """
     return lambda x, f=f, g=g: f(g(x))
 
+def join_normalisers(*a):
+    """
+    Compose functions, e.g.
+
+       join_normalisers(f1,f2,f3)
+
+    is the same as
+
+       lambda x: f1(f2(f3(x)))
+    """
+
+    assert all(callable(f) for f in a)
+
+    fn = lambda x:x # identity function
+    for f in a:
+        fn = lambda x,f=f,fn=fn: fn(f(x))
+    return fn
+
 # ----
 # Function for composing two opt-fns together
 
@@ -1004,8 +1025,10 @@ def do_compile( name, way, should_fail, top_mod, extra_mods, extra_hc_opts, over
     (platform_specific, expected_stderr_file) = platform_wordsize_qualify(namebase, 'stderr')
     actual_stderr_file = qualify(name, 'comp.stderr')
 
-    if not compare_outputs('stderr', \
-                           two_normalisers(two_normalisers(getTestOpts().extra_errmsg_normaliser, normalise_errmsg), normalise_whitespace), \
+    if not compare_outputs('stderr',
+                           join_normalisers(getTestOpts().extra_errmsg_normaliser,
+                                            normalise_errmsg,
+                                            normalise_whitespace),
                            expected_stderr_file, actual_stderr_file):
         return failBecause('stderr mismatch')
 

testsuite/tests/safeHaskell/check/pkg01/all.T

@@ -8,6 +8,9 @@ def normaliseArrayPackage(str):
 def normaliseBytestringPackage(str):
     return re.sub('bytestring-[0-9]+(\.[0-9]+)*', 'bytestring-<VERSION>', str)
 
+def normaliseIntegerPackage(str):
+    return re.sub('integer-(gmp|simple)-[0-9.]+', 'integer-<IMPL>-<VERSION>', str)
+
 def normaliseArrayPackageKey(str):
     return re.sub('array_[A-Za-z0-9]+', 'array_<HASH>', str)
 
@@ -38,10 +41,11 @@ make_args = 'VANILLA=' + vanilla + ' PROF=' + prof + ' DYN=' + dyn
 test('safePkg01',
      [clean_cmd('$MAKE -s --no-print-directory cleanPackageDatabase.safePkg01'),
       normalise_errmsg_fun(ignoreLdOutput),
-      normalise_fun(two_normalisers(two_normalisers(normaliseArrayPackage,
-                                                    normaliseArrayPackageKey),
-                                    normaliseBytestringPackage))],
-     run_command, 
+      normalise_fun(join_normalisers(
+        normaliseArrayPackage,
+        normaliseArrayPackageKey,
+        normaliseBytestringPackage))],
+     run_command,
      ['$MAKE -s --no-print-directory safePkg01 ' + make_args])
 
 # Fail since we enable package trust