--- a/testing/docker/lint/system-setup.sh
+++ b/testing/docker/lint/system-setup.sh
@@ -6,17 +6,16 @@ set -ve
 
 test `whoami` == 'root'
 
 mkdir -p /setup
 cd /setup
 
 apt_packages=()
 apt_packages+=('curl')
-apt_packages+=('mercurial')
 apt_packages+=('python')
 apt_packages+=('python-pip')
 apt_packages+=('sudo')
 apt_packages+=('xz-utils')
 
 apt-get update
 apt-get install -y ${apt_packages[@]}
 
@@ -26,16 +25,51 @@ locale-gen en_US.UTF-8
 dpkg-reconfigure locales
 
 tooltool_fetch() {
     cat >manifest.tt
     /build/tooltool.py fetch
     rm manifest.tt
 }
 
+# Install Mercurial
+
+cd $BUILD
+tooltool_fetch <<EOF
+[
+{
+    "size": 44878,
+    "digest": "7b1fc1217e0dcaeea852b0af2dc559b1aafb704fbee7e29cbec75af57bacb84910a7ec92b5c33f04ee98f23b3a57f1fa451173fe7c8a96f58faefe319dc7dde1",
+    "algorithm": "sha512",
+    "filename": "mercurial_3.8.4_amd64.deb"
+},
+{
+    "size": 1818422,
+    "digest": "b476e2612e7495a1c7c5adfd84511aa7479e26cc9070289513ec705fbfc4c61806ce2dbcceca0e63f2e80669be416f3467a3cebb522dcb8a6aeb62cdd3df82f2",
+    "algorithm": "sha512",
+    "filename": "mercurial-common_3.8.4_all.deb"
+}
+]
+EOF
+
+dpkg -i mercurial-common_3.8.4_all.deb mercurial_3.8.4_amd64.deb
+
+mkdir -p /etc/mercurial
+cat >/etc/mercurial/hgrc <<EOF
+# By default the progress bar starts after 3s and updates every 0.1s. We
+# change this so it shows and updates every 1.0s.
+[progress]
+delay = 1.0
+refresh = 1.0
+
+[web]
+cacerts = /etc/ssl/certs/ca-certificates.crt
+EOF
+
+chmod 644 /etc/mercurial/hgrc
 
 ###
 # ESLint Setup
 ###
 
 # install node
 
 # For future reference things like this don't need to be uploaded to tooltool, as long