diff --git a/environments/drupal-7.sh b/environments/drupal-7.sh
index 6f948d2..7e8367b 100644
--- a/environments/drupal-7.sh
+++ b/environments/drupal-7.sh
@@ -2,9 +2,16 @@
 # @file
 # Drupal-7 environment variables and functions.
 
-function drupal_ti_install_drupal() {
+function drupal_ti_download_drupal() {
 	drush --yes dl drupal-7 --drupal-project-rename=drupal
-	cd drupal
+}
+
+function drupal_ti_install_drupal() {
+	if [ ! -f install.php ]
+	then
+		return -1
+	fi
+
 	php -d sendmail_path=$(which true) ~/.composer/vendor/bin/drush.php --yes site-install testing --db-url="$DRUPAL_TI_DB_URL"
 	drush use $(pwd)#default
 }
diff --git a/environments/drupal-8.sh b/environments/drupal-8.sh
index 55825ab..2e0ee9e 100644
--- a/environments/drupal-8.sh
+++ b/environments/drupal-8.sh
@@ -2,9 +2,15 @@
 # @file
 # Drupal-8 environment variables and functions.
 
-function drupal_ti_install_drupal() {
+function drupal_ti_download_drupal() {
 	git clone --depth 1 --branch 8.0.x http://git.drupal.org/project/drupal.git
-	cd drupal
+}
+
+function drupal_ti_install_drupal() {
+	if [ ! -f install.php ]
+	then
+		return -1
+	fi
 	php -d sendmail_path=$(which true) ~/.composer/vendor/bin/drush.php --yes -v site-install minimal --db-url="$DRUPAL_TI_DB_URL"
 	drush use $(pwd)#default
 }
diff --git a/functions/drupal.sh b/functions/drupal.sh
index 122bbd1..3115228 100644
--- a/functions/drupal.sh
+++ b/functions/drupal.sh
@@ -3,7 +3,7 @@
 # Common functionality for common tasks.
 
 #
-# Ensures that the right Drupal version is installed.
+# Ensures that the right Drupal version exists.
 #
 function drupal_ti_ensure_drupal() {
 	# This function is re-entrant.
@@ -23,12 +23,22 @@ function drupal_ti_ensure_drupal() {
 		export PATH="$BIN_DIR:$PATH"
 	fi
 
-	# Create database and install Drupal.
-	mysql -e "create database $DRUPAL_TI_DB"
-
 	mkdir -p "$DRUPAL_TI_DRUPAL_BASE"
 	cd "$DRUPAL_TI_DRUPAL_BASE"
 
+	drupal_ti_download_drupal
+}
+
+#
+# Ensures that Drupal is installed.
+#
+function drupal_ti_ensure_drupal_installed() {
+	drupal_ti_ensure_drupal
+
+	# Create database and install Drupal.
+	mysql -e "create database $DRUPAL_TI_DB"
+
+	cd drupal
 	drupal_ti_install_drupal
 }
 
diff --git a/runners/behat/before_script.sh b/runners/behat/before_script.sh
index cebdd15..7afe134 100755
--- a/runners/behat/before_script.sh
+++ b/runners/behat/before_script.sh
@@ -4,7 +4,7 @@
 set -e $DRUPAL_TI_DEBUG
 
 # Ensure the right Drupal version is installed.
-drupal_ti_ensure_drupal
+drupal_ti_ensure_drupal_installed
 
 # Ensure the module is linked into the code base and enabled.
 drupal_ti_ensure_module
diff --git a/runners/phpunit-core/before_script.sh b/runners/phpunit-core/before_script.sh
index 43586b3..4801f8f 100755
--- a/runners/phpunit-core/before_script.sh
+++ b/runners/phpunit-core/before_script.sh
@@ -3,8 +3,8 @@
 
 set -e $DRUPAL_TI_DEBUG
 
-# Ensure the right Drupal version is installed.
+# Ensure the right Drupal version is downloaded.
 drupal_ti_ensure_drupal
 
-# Ensure the module is linked into the code base and enabled.
-drupal_ti_ensure_module
+# Ensure the module is linked into the code base.
+drupal_ti_ensure_module_linked
diff --git a/runners/simpletest/before_script.sh b/runners/simpletest/before_script.sh
index 5a526b6..1876359 100755
--- a/runners/simpletest/before_script.sh
+++ b/runners/simpletest/before_script.sh
@@ -4,7 +4,7 @@
 set -e $DRUPAL_TI_DEBUG
 
 # Ensure the right Drupal version is installed.
-drupal_ti_ensure_drupal
+drupal_ti_ensure_drupal_installed
 
 # Enable simpletest module.
 cd "$DRUPAL_TI_DRUPAL_DIR"