tests: add repository check for pyflakes test

If this test was run from a tarball with no Mercurial repository, it
would fail because 'hg manifest' didn't work.

tests/hghave.py

@@ -259,6 +259,10 b' def has_system_sh():'
 def has_serve():
     return os.name != 'nt' # gross approximation
 
+def has_test_repo():
+    t = os.environ["TESTDIR"]
+    return os.path.isdir(os.path.join(t, "..", ".hg"))
+
 def has_tic():
     try:
         import curses
@@ -317,6 +321,7 b' checks = {'
     "svn-bindings": (has_svn_bindings, "subversion python bindings"),
     "symlink": (has_symlink, "symbolic links"),
     "system-sh": (has_system_sh, "system() uses sh"),
+    "test-repo": (has_test_repo, "running tests from repository"),
     "tic": (has_tic, "terminfo compiler and curses module"),
     "tla": (has_tla, "GNU Arch tla client"),
     "unix-permissions": (has_unix_permissions, "unix-style permissions"),

tests/test-check-pyflakes.t

@@ -1,8 +1,10 b''
-  $ "$TESTDIR/hghave" pyflakes || exit 80
+#if test-repo pyflakes
+
   $ cd "`dirname "$TESTDIR"`"
 
 run pyflakes on all tracked files ending in .py or without a file ending
 (skipping binary file random-seed)
+
   $ hg manifest 2>/dev/null | egrep "\.py$|^[^.]*$" | grep -v /random_seed$ \
   > | xargs pyflakes 2>/dev/null | "$TESTDIR/filterpyflakes.py"
   contrib/win32/hgwebdir_wsgi.py:*: 'win32traceutil' imported but unused (glob)
@@ -16,4 +18,4 b' run pyflakes on all tracked files ending'
   tests/hghave.py:*: 'ssl' imported but unused (glob)
   contrib/win32/hgwebdir_wsgi.py:93: 'from isapi.install import *' used; unable to detect undefined names (glob)
   
-
+#endif