--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tests/helpers-testrepo.sh	Tue Nov 28 22:49:58 2017 -0800
@@ -0,0 +1,53 @@
+# In most cases, the mercurial repository can be read by the bundled hg, but
+# that isn't always true because third-party extensions may change the store
+# format, for example. In which case, the system hg installation is used.
+#
+# We want to use the hg version being tested when interacting with the test
+# repository, and the system hg when interacting with the mercurial source code
+# repository.
+#
+# The mercurial source repository was typically orignally cloned with the
+# system mercurial installation, and may require extensions or settings from
+# the system installation.
+syshg () {
+    (
+        syshgenv
+        exec hg "$@"
+    )
+}
+
+# Revert the environment so that running "hg" runs the system hg
+# rather than the test hg installation.
+syshgenv () {
+    . "$HGTEST_RESTOREENV"
+    HGPLAIN=1
+    export HGPLAIN
+}
+
+# The test-repo is a live hg repository which may have evolution markers
+# created, e.g. when a ~/.hgrc enabled evolution.
+#
+# Tests may be run using a custom HGRCPATH, which do not enable evolution
+# markers by default.
+#
+# If test-repo includes evolution markers, and we do not enable evolution
+# markers, hg will occasionally complain when it notices them, which disrupts
+# tests resulting in sporadic failures.
+#
+# Since we aren't performing any write operations on the test-repo, there's
+# no harm in telling hg that we support evolution markers, which is what the
+# following lines for the hgrc file do:
+cat >> "$HGRCPATH" << EOF
+[experimental]
+evolution = createmarkers
+EOF
+
+# Use the system hg command if the bundled hg can't read the repository with
+# no warning nor error.
+if [ -n "`hg id -R "$TESTDIR/.." 2>&1 >/dev/null`" ]; then
+    alias testrepohg=syshg
+    alias testrepohgenv=syshgenv
+else
+    alias testrepohg=hg
+    alias testrepohgenv=:
+fi

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tests/test-check-pyflakes.t	Tue Nov 28 22:49:58 2017 -0800
@@ -0,0 +1,19 @@
+#require test-repo pyflakes hg10
+
+  $ . "$TESTDIR/helpers-testrepo.sh"
+
+run pyflakes on all tracked files ending in .py or without a file ending
+(skipping binary file random-seed)
+
+  $ cat > test.py <<EOF
+  > print(undefinedname)
+  > EOF
+  $ pyflakes test.py 2>/dev/null
+  test.py:1: undefined name 'undefinedname'
+  [1]
+  $ cd "`dirname "$TESTDIR"`"
+
+  $ testrepohg locate 'set:**.py or grep("^#!.*python")' \
+  > -X tests/ \
+  > 2>/dev/null \
+  > | xargs pyflakes 2>/dev/null