diff --git a/test/etaoin/proc_test.clj b/test/etaoin/proc_test.clj
new file mode 100644
index 00000000..ae486f03
--- /dev/null
+++ b/test/etaoin/proc_test.clj
@@ -0,0 +1,40 @@
+(ns etaoin.proc-test
+  (:require [etaoin.api :refer :all]
+            [clojure.java.shell :refer [sh]]
+            [clojure.test :refer :all]
+            [etaoin.proc :as proc]
+            [clojure.string :as str]))
+
+(defn get-count-chromedriver-processes
+  []
+  (->> (sh "sh" "-c" "ps aux | grep chromedriver")
+       :out
+       str/split-lines
+       (drop-last 2)
+       count))
+
+(deftest test-prevent-process-fork
+  (testing "certain driver port"
+    (let [port    9999
+          process (proc/run ["chromedriver" (format "--port=%d" port)])
+          _       (wait-running (atom {:port port :host "localhost"}))]
+      (is (= 1 (get-count-chromedriver-processes)))
+      (is (thrown-with-msg?
+            clojure.lang.ExceptionInfo
+            #"already in use"
+            (chrome {:port port})))
+      (proc/kill process)))
+  (testing "random driver port"
+    (let [port    9999
+          process (proc/run ["chromedriver" (format "--port=%d" port)])
+          _       (wait-running (atom {:port port :host "localhost"}))]
+      (with-chrome {:args ["--no-sandbox"]} driver
+        (is (= 2 (get-count-chromedriver-processes)))
+        (proc/kill process))))
+  (testing "connect to driver"
+    (let [port    9999
+          process (proc/run ["chromedriver" (format "--port=%d" port)])
+          _       (wait-running (atom {:port port :host "localhost"}))
+          driver  (chrome {:host "localhost" :port port :args ["--no-sandbox"]})]
+      (is (= 1 (get-count-chromedriver-processes)))
+      (proc/kill process))))