tests: enable import checker for tests/**.py files

Several known-bad files are excluded as they couldn't be trivially fixed.
In principle, we should fix them first, however, it would have more risk
to keep Py3k porting going without the test coverage.

Still contrib/**.py aren't covered, which needs another round.

tests/test-check-module-imports.t

@@ -1,146 +1,155
 #require test-repo
 
   $ import_checker="$TESTDIR"/../contrib/import-checker.py
 
 Run the doctests from the import checker, and make sure
 it's working correctly.
   $ TERM=dumb
   $ export TERM
   $ python -m doctest $import_checker
 
 Run additional tests for the import checker
 
   $ mkdir testpackage
 
   $ cat > testpackage/multiple.py << EOF
   > from __future__ import absolute_import
   > import os, sys
   > EOF
 
   $ cat > testpackage/unsorted.py << EOF
   > from __future__ import absolute_import
   > import sys
   > import os
   > EOF
 
   $ cat > testpackage/stdafterlocal.py << EOF
   > from __future__ import absolute_import
   > from . import unsorted
   > import os
   > EOF
 
   $ cat > testpackage/requirerelative.py << EOF
   > from __future__ import absolute_import
   > import testpackage.unsorted
   > EOF
 
   $ cat > testpackage/importalias.py << EOF
   > from __future__ import absolute_import
   > import ui
   > EOF
 
   $ cat > testpackage/relativestdlib.py << EOF
   > from __future__ import absolute_import
   > from .. import os
   > EOF
 
   $ cat > testpackage/symbolimport.py << EOF
   > from __future__ import absolute_import
   > from .unsorted import foo
   > EOF
 
   $ cat > testpackage/latesymbolimport.py << EOF
   > from __future__ import absolute_import
   > from . import unsorted
   > from mercurial.node import hex
   > EOF
 
   $ cat > testpackage/multiplegroups.py << EOF
   > from __future__ import absolute_import
   > from . import unsorted
   > from . import more
   > EOF
 
   $ mkdir testpackage/subpackage
   $ cat > testpackage/subpackage/levelpriority.py << EOF
   > from __future__ import absolute_import
   > from . import foo
   > from .. import parent
   > EOF
 
   $ touch testpackage/subpackage/foo.py
   $ cat > testpackage/subpackage/__init__.py << EOF
   > from __future__ import absolute_import
   > from . import levelpriority  # should not cause cycle
   > EOF
 
   $ cat > testpackage/subpackage/localimport.py << EOF
   > from __future__ import absolute_import
   > from . import foo
   > def bar():
   >     # should not cause "higher-level import should come first"
   >     from .. import unsorted
   >     # but other errors should be detected
   >     from .. import more
   >     import testpackage.subpackage.levelpriority
   > EOF
 
   $ cat > testpackage/importmodulefromsub.py << EOF
   > from __future__ import absolute_import
   > from .subpackage import foo  # not a "direct symbol import"
   > EOF
 
   $ cat > testpackage/importsymbolfromsub.py << EOF
   > from __future__ import absolute_import
   > from .subpackage import foo, nonmodule
   > EOF
 
   $ cat > testpackage/sortedentries.py << EOF
   > from __future__ import absolute_import
   > from . import (
   >     foo,
   >     bar,
   > )
   > EOF
 
   $ cat > testpackage/importfromalias.py << EOF
   > from __future__ import absolute_import
   > from . import ui
   > EOF
 
   $ cat > testpackage/importfromrelative.py << EOF
   > from __future__ import absolute_import
   > from testpackage.unsorted import foo
   > EOF
 
   $ python "$import_checker" testpackage/*.py testpackage/subpackage/*.py
   testpackage/importalias.py:2: ui module must be "as" aliased to uimod
   testpackage/importfromalias.py:2: ui from testpackage must be "as" aliased to uimod
   testpackage/importfromrelative.py:2: import should be relative: testpackage.unsorted
   testpackage/importfromrelative.py:2: direct symbol import foo from testpackage.unsorted
   testpackage/importsymbolfromsub.py:2: direct symbol import nonmodule from testpackage.subpackage
   testpackage/latesymbolimport.py:3: symbol import follows non-symbol import: mercurial.node
   testpackage/multiple.py:2: multiple imported names: os, sys
   testpackage/multiplegroups.py:3: multiple "from . import" statements
   testpackage/relativestdlib.py:2: relative import of stdlib module
   testpackage/requirerelative.py:2: import should be relative: testpackage.unsorted
   testpackage/sortedentries.py:2: imports from testpackage not lexically sorted: bar < foo
   testpackage/stdafterlocal.py:3: stdlib import "os" follows local import: testpackage
   testpackage/subpackage/levelpriority.py:3: higher-level import should come first: testpackage
   testpackage/subpackage/localimport.py:7: multiple "from .. import" statements
   testpackage/subpackage/localimport.py:8: import should be relative: testpackage.subpackage.levelpriority
   testpackage/symbolimport.py:2: direct symbol import foo from testpackage.unsorted
   testpackage/unsorted.py:3: imports not lexically sorted: os < sys
   [1]
 
   $ cd "$TESTDIR"/..
 
 There are a handful of cases here that require renaming a module so it
 doesn't overlap with a stdlib module name. There are also some cycles
 here that we should still endeavor to fix, and some cycles will be
 hidden by deduplication algorithm in the cycle detector, so fixing
 these may expose other cycles.
 
-  $ hg locate 'mercurial/**.py' 'hgext/**.py' | sed 's-\\-/-g' | python "$import_checker" -
+Known-bad files are excluded by -X as some of them would produce unstable
+outputs, which should be fixed later.
+
+  $ hg locate 'mercurial/**.py' 'hgext/**.py' 'tests/**.py' \
+  > -X tests/test-hgweb-auth.py \
+  > -X tests/hypothesishelpers.py \
+  > -X tests/test-ctxmanager.py \
+  > -X tests/test-lock.py \
+  > -X tests/test-verify-repo-operations.py \
+  > | sed 's-\\-/-g' | python "$import_checker" -
   Import cycle: hgext.largefiles.basestore -> hgext.largefiles.localstore -> hgext.largefiles.basestore
   [1]