diff --git a/tests/letstest/scripts/test_sdists.sh b/tests/letstest/scripts/test_sdists.sh
index a8d0362fa..ad729e0eb 100755
--- a/tests/letstest/scripts/test_sdists.sh
+++ b/tests/letstest/scripts/test_sdists.sh
@@ -9,31 +9,31 @@ VENV_PATH=venv
 . $BOOTSTRAP_SCRIPT
 
 # setup venv
-# We strip the hashes because the venv creation script includes unhashed
-# constraints in the commands given to pip and the mix of hashed and unhashed
-# packages makes pip error out.
-python3 tools/strip_hashes.py tools/pipstrap_constraints.txt > constraints.txt
-python3 tools/strip_hashes.py tools/certbot_constraints.txt > requirements.txt
+python3 -m venv $VENV_PATH
+$VENV_PATH/bin/python3 tools/pipstrap.py
+. "$VENV_PATH/bin/activate"
+# pytest is needed to run tests on our packages so we install a pinned version here.
+tools/pip_install.py pytest
+
+# setup constraints
+TEMP_DIR=$(mktemp -d)
+CONSTRAINTS="$TEMP_DIR/constraints.txt"
+# We strip the hashes because we don't have hashes of our local packages and
+# the mix of hashed and unhashed packages makes pip error out.
+python3 tools/strip_hashes.py tools/certbot_constraints.txt > "$CONSTRAINTS"
+python3 tools/strip_hashes.py tools/pipstrap_constraints.txt >> "$CONSTRAINTS"
 
 # We pin cryptography to 3.1.1 and pyOpenSSL to 19.1.0 specifically for CentOS 7 / RHEL 7
 # because these systems ship only with OpenSSL 1.0.2, and this OpenSSL version support has been
 # dropped on cryptography>=3.2 and pyOpenSSL>=20.0.0.
 # Using this old version of OpenSSL would break the cryptography and pyOpenSSL wheels builds.
 if [ -f /etc/redhat-release ] && [ "$(. /etc/os-release 2> /dev/null && echo "$VERSION_ID" | cut -d '.' -f1)" -eq 7 ]; then
-  sed -i 's|cryptography==.*|cryptography==3.1.1|g' requirements.txt
-  sed -i 's|pyOpenSSL==.*|pyOpenSSL==19.1.0|g' requirements.txt
+  sed -i 's|cryptography==.*|cryptography==3.1.1|g' "$CONSTRAINTS"
+  sed -i 's|pyOpenSSL==.*|pyOpenSSL==19.1.0|g' "$CONSTRAINTS"
 fi
 
-python3 -m venv $VENV_PATH
-$VENV_PATH/bin/python3 tools/pipstrap.py
-PIP_CONSTRAINT=constraints.txt PIP_NO_BINARY=:all: $VENV_PATH/bin/python3 -m pip install --requirement requirements.txt
-. "$VENV_PATH/bin/activate"
-# pytest is needed to run tests on some of our packages so we install a pinned version here.
-tools/pip_install.py pytest
 
 PLUGINS="certbot-apache certbot-nginx"
-TEMP_DIR=$(mktemp -d)
-
 # build sdists
 for pkg_dir in acme certbot $PLUGINS; do
     cd $pkg_dir
@@ -50,8 +50,7 @@ cd $TEMP_DIR
 for pkg in acme certbot $PLUGINS; do
     tar -xvf "$pkg-$VERSION.tar.gz"
     cd "$pkg-$VERSION"
-    python setup.py build
+    PIP_CONSTRAINT=../constraints.txt PIP_NO_BINARY=:all: pip install .
     python -m pytest
-    python setup.py install
     cd -
 done