diff --git a/project.clj b/project.clj
index 0fad771..22c64df 100644
--- a/project.clj
+++ b/project.clj
@@ -7,7 +7,8 @@
   :dependencies [[org.clojure/clojure "1.10.1"]
                  [org.testcontainers/testcontainers "1.14.3"]]
   :plugins [[metosin/bat-test "0.4.4"]]
-  :bat-test {:report [:pretty {:type :junit 
+  :bat-test {:report [:pretty {:type :junit
                                :output-to "target/junit.xml"}]}
+  :profiles {:dev {:dependencies [[org.testcontainers/postgresql "1.14.3"]]}}
   :target-path "target/%s")
 
diff --git a/src/clj_test_containers/core.clj b/src/clj_test_containers/core.clj
index dc307a7..14b2075 100644
--- a/src/clj_test_containers/core.clj
+++ b/src/clj_test_containers/core.clj
@@ -13,8 +13,8 @@
 
 (defn create
   "Sets the properties for a testcontainer instance"
-  [{:keys [image-name exposed-ports env-vars command]}]
-  (let [container (GenericContainer. image-name)]
+  [{:keys [container image-name exposed-ports env-vars command]}]
+  (let [container (or container (GenericContainer. image-name))]
     (.setExposedPorts container (map int exposed-ports))
 
     (if (some? env-vars)
diff --git a/test/clj_test_containers/core_test.clj b/test/clj_test_containers/core_test.clj
index 9e9de05..f373315 100644
--- a/test/clj_test_containers/core_test.clj
+++ b/test/clj_test_containers/core_test.clj
@@ -1,6 +1,8 @@
 (ns clj-test-containers.core-test
   (:require [clojure.test :refer :all]
-            [clj-test-containers.core :refer :all]))
+            [clj-test-containers.core :refer :all])
+  (:import [org.testcontainers.containers
+            PostgreSQLContainer]))
 
 (deftest init-test
   (testing "Testing basic testcontainer generic image initialisation"
@@ -19,7 +21,17 @@
 
   (testing "Executing a command in the running Docker container"
     (let [container (create {:image-name "postgres:12.2"
-                             :exposed-ports [5432] 
+                             :exposed-ports [5432]
+                             :env-vars {"POSTGRES_PASSWORD" "pw"}})
+          initialized-container (start! container)
+          result (execute-command! initialized-container ["whoami"])
+          stopped-container (stop! container)]
+      (is (= 0 (:exit-code result)))
+      (is (= "root\n" (:stdout result)))))
+
+  (testing "Executing a command in the running Docker container with a custom container"
+    (let [container (create {:container (PostgreSQLContainer. "postgres:12.2")
+                             :exposed-ports [5432]
                              :env-vars {"POSTGRES_PASSWORD" "pw"}})
           initialized-container (start! container)
           result (execute-command! initialized-container ["whoami"])