diff --git a/.gitignore b/.gitignore
index b33c1aab8..8191c173b 100644
--- a/.gitignore
+++ b/.gitignore
@@ -46,6 +46,7 @@ zope.interface-*.egg
 /.hypothesis/
 /eliot.log
 /misc/python3/results.xml
+/misc/python3/results.subunit2
 
 # This is the plaintext of the private environment needed for some CircleCI
 # operations.  It's never supposed to be checked in.
diff --git a/misc/python3/depgraph.sh b/misc/python3/depgraph.sh
index a1ef21142..d5ad33bf7 100755
--- a/misc/python3/depgraph.sh
+++ b/misc/python3/depgraph.sh
@@ -10,7 +10,7 @@ cd tahoe-depgraph
 # Generate the maybe-changed data.
 python "${TAHOE}"/misc/python3/tahoe-depgraph.py "${TAHOE}"
 
-if git diff-index --quiet HEAD tahoe-deps.json tahoe-ported.json; then
+if git diff-index --quiet HEAD; then
   echo "Declining to commit without any changes."
   exit 0
 fi
diff --git a/misc/python3/passing b/misc/python3/ratchet-passing
similarity index 100%
rename from misc/python3/passing
rename to misc/python3/ratchet-passing
diff --git a/misc/python3/ratchet.py b/misc/python3/ratchet.py
index 136fdcf4c..cb672cf67 100755
--- a/misc/python3/ratchet.py
+++ b/misc/python3/ratchet.py
@@ -26,9 +26,6 @@ The exit codes are:
   1 - changes observed, whether welcome or unwelcome
   2 - invocation error
 
-Be sure to call as `./ratchet.py` and not `python ratchet.py` if you want to
-see our exit code instead of Python's.
-
 If <junitxml file path> does not exist, you'll get a FileNotFoundError:
 
     >>> _test('up', None, None)                                                # doctest: +ELLIPSIS
@@ -231,6 +228,7 @@ def main(direction, junitxml_path, tracking_path):
     results = JUnitXMLFile(junitxml_path).parse()
 
     if tracking_path == '...':
+        # Shortcut to aid in debugging XML parsing issues.
         results.report()
         return
 
diff --git a/misc/python3/ratchet.sh b/misc/python3/ratchet.sh
index 00acd60c3..a6a2c53c3 100755
--- a/misc/python3/ratchet.sh
+++ b/misc/python3/ratchet.sh
@@ -1,10 +1,18 @@
 #!/usr/bin/env bash
-base="$(dirname $0)"
-tracking="passing"
+set -euxo pipefail
+tracking_filename="ratchet-passing"
 
-# trial outputs some things that are only git-ignored in the root, so don't cd quite yet ...
+# Start somewhere predictable.
+cd "$(dirname $0)"
+base=$(pwd)
+
+# Actually, though, trial outputs some things that are only gitignored in the project root.
+cd "../.."
+
+# Since both of the next calls are expected to exit non-0, relax our guard.
 set +e
-trial --reporter subunitv2 allmydata | subunit2junitxml > "$base/results.xml"
+SUBUNITREPORTER_OUTPUT_PATH="$base/results.subunit2" trial --reporter subunitv2-file allmydata
+subunit2junitxml < "$base/results.subunit2" > "$base/results.xml"
 set -e
 
 # Okay, now we're clear.
@@ -13,11 +21,9 @@ cd "$base"
 # Make sure ratchet.py itself is clean.
 python3 -m doctest ratchet.py
 
-# Now see about Tahoe-LAFS ...
+# Now see about Tahoe-LAFS (also expected to fail) ...
 set +e
-# P.S. Don't invoke as `python ratchet.py ...` because then Python swallows the
-# exit code.
-./ratchet.py up results.xml "$tracking"
+python3 ratchet.py up results.xml "$tracking_filename"
 code=$?
 set -e
 
@@ -26,6 +32,6 @@ set -e
 if [ $TERM = 'dumb' ]; then
   export TERM=ansi
 fi
-git diff "$tracking"
+git diff "$tracking_filename"
 
 exit $code
diff --git a/setup.py b/setup.py
index 3a7d8ef8c..f22ca0f4c 100644
--- a/setup.py
+++ b/setup.py
@@ -142,6 +142,7 @@ tor_requires = [
 
 i2p_requires = [
     # txi2p has Python 3 support, but it's unreleased: https://github.com/str4d/txi2p/issues/10.
+    # URL lookups are in PEP-508 (via https://stackoverflow.com/a/54794506).
     # Also see the comment in tor_requires.
     "txi2p @ git+https://github.com/str4d/txi2p@0611b9a86172cb70d2f5e415a88eee9f230590b3#egg=txi2p",
 ]