diff --git a/.tmux b/.tmux
index 9e021e4..6131250 100755
--- a/.tmux
+++ b/.tmux
@@ -20,7 +20,7 @@ tmux send-keys -t "${session_name}:vim" "nvim" Enter
 tmux split-pane -t "${session_name}:vim" -h -c "${session_path}" -p 40
 tmux send-keys -t "${session_name}:vim.right" "php -S 0.0.0.0:9000 -t web" Enter
 tmux split-pane -t "${session_name}:vim" -c "${session_path}" -v
-tmux send-keys -t "${session_name}:vim.bottom-right" "paratest && watch-changes web/modules/custom paratest" Enter
+tmux send-keys -t "${session_name}:vim.bottom-right" "./run test && watch-changes web/modules/custom ./run test" Enter
 
 # 2. General shell use.
 tmux new-window -t "${session_name}" -c "${session_path}"
diff --git a/run b/run
new file mode 100755
index 0000000..652a577
--- /dev/null
+++ b/run
@@ -0,0 +1,23 @@
+#!/usr/bin/env bash
+
+set -o errexit
+set -o nounset
+
+PATH=${PATH}:./vendor/bin
+
+# Display a list of all available commands.
+function help {
+  printf "%s <task> [args]\n\nTasks:\n" "${0}"
+
+  compgen -A function | grep -v "^_" | cat -n
+
+  printf "\nExtended help:\n  Each task has comments for general usage\n"
+}
+
+# Run PHPUnit tests.
+function test {
+  paratest --group lessons "${@}"
+}
+
+TIMEFORMAT=$'\nTask completed in %3lR'
+time "${@:-help}"