tests: add a tool for mass updates

When we update some output format, too many adjustements must be made
by hand.  This script updates most tests based on the actual output
made during the tests.

* build-aux/update-test: New.

build-aux/update-test

@@ -0,0 +1,93 @@
+#! /usr/bin/env python
+
+# usage:
+# update-test _build/8d/tests/testsuite.dir/*.testsuite.log
+
+import argparse
+import os
+import re
+
+
+def getargs():
+    p = argparse.ArgumentParser(description='Update test cases.')
+    opt = p.add_argument
+    opt('tests', metavar='test', nargs='+', type=str, default=None,
+        help='test files to update')
+    opt('-v', '--verbose', action='store_true',
+        help='Be verbose')
+    return p.parse_args()
+
+args = getargs()
+subst = dict()
+
+
+def log(*args_):
+    if args.verbose:
+        print(*args_)
+
+
+def contents(file):
+    '''The contents of a file.'''
+    log(file)
+    f = open(file)
+    return f.read()
+
+
+def diff_to_re(match):
+    '''Convert a portion of patch into a regex substitution to perform.
+    No longer used, we now use the expected/effective parts.
+    '''
+    frm = []
+    to = []
+    is_diff = False
+    for l in match.group(1).splitlines():
+        print(l)
+        # t in [-+ ]
+        t = l[0]
+        l = l[1:]
+        if t in ['-', ' ']:
+            is_diff = True
+            frm.append(l)
+        if t in ['+', ' ']:
+            is_diff = True
+            to.append(l)
+    if is_diff:
+        frm = "\n".join(frm)
+        to = "\n".join(to)
+        subst[frm] = to
+
+
+def update(at_file, logfile):
+    test = contents(at_file)
+    if os.path.isfile(logfile):
+        log("LOG: ", logfile)
+        l = contents(logfile)
+        log("LOG: ", l)
+        global subst
+        subst = {}
+        re.sub(r'(?:^@@.*\n)((?:^[-+ ].*\n)+)',
+               diff_to_re, l, flags = re.MULTILINE)
+        print(subst)
+        if subst:
+            # Turn "subst{frm} -> to" into a large RE.
+            frm = '|'.join([re.escape(x) for x in subst])
+            log("FROM:", frm)
+            test = re.sub("(" + frm + ")",
+                          lambda m: subst[m.group(1)],
+                          test, flags=re.MULTILINE)
+    open(at_file, 'w').write(test)
+
+
+def process(logfile):
+    log = contents(logfile)
+    # Look for the file to update.
+    m = re.search(r'^\d+\. (\w+\.at):\d+: ', log, re.MULTILINE)
+    if not m:
+        return
+    at_file = 'tests/' + m.group(1)
+    print(at_file)
+    update(at_file, logfile)
+
+for t in args.tests:
+    log("FILE:", t)
+    process(t)