necessary but not sufficient

.circleci/bootstrap-test-environment.sh

@@ -1,4 +1,4 @@
-#!/bin/sh
+#!/bin/bash -eo pipefail
 
 # Avoid the /nonexistent home directory in nobody's /etc/passwd entry.
 usermod --home /tmp/nobody nobody

.circleci/run-tests.sh

@@ -1,4 +1,4 @@
-#!/bin/sh
+#!/bin/bash -eo pipefail
 
 # Run the test suite as a non-root user.  This is the expected usage some
 # small areas of the test suite assume non-root privileges (such as unreadable

.circleci/setup-virtualenv.sh

@@ -1,4 +1,4 @@
-#!/bin/sh
+#!/bin/bash -eo pipefail
 
 # Set up the virtualenv as a non-root user so we can run the test suite as a
 # non-root user.  See below.