diff --git a/test/milquetoast/client.clj b/test/milquetoast/client.clj
index 5340305..3357600 100644
--- a/test/milquetoast/client.clj
+++ b/test/milquetoast/client.clj
@@ -6,3 +6,38 @@
 (t/deftest test-create-mqtt-client!
   (t/testing "create-mqtt-client! returns an instance of MqttClient"
     (t/is (instance? MqttClient (sut/create-mqtt-client! :broker-uri "tcp://localhost:1883")))))
+
+(t/deftest test-retry-attempt
+  (t/testing "retry-attempt retries function execution upon RuntimeException"
+    (let [attempt-count (atom 0)]
+      (sut/retry-attempt false
+                         (fn []
+                           (swap! attempt-count inc)
+                           (when (< @attempt-count 3)
+                             (throw (RuntimeException. "Test exception"))))
+                         #(println "Reconnecting..."))
+      (t/is (= 3 @attempt-count)))))
+
+(t/deftest test-create-message
+  (t/testing "create-message creates an MQTT message with the provided options"
+    (let [msg (sut/create-message "test" {:qos 2 :retain true})]
+      (t/is (= 2 (.getQos msg)))
+      (t/is (.isRetained msg)))))
+
+(t/deftest test-parse-message
+  (t/testing "parse-message parses an MQTT message into a map"
+    (let [mqtt-msg (sut/create-message "test" {:qos 2 :retain true})
+          parsed-msg (sut/parse-message mqtt-msg)]
+      (t/is (= 2 (:qos parsed-msg)))
+      (t/is (:retained parsed-msg)))))
+
+(t/deftest test-parallelism
+  (t/testing "parallelism returns the number of available processors plus one"
+    (t/is (= (inc (.availableProcessors (Runtime/getRuntime))) (sut/parallelism)))))
+
+(t/deftest test-json-parse-message
+  (t/testing "json-parse-message parses the payload of an MQTT message into a map and adds a timestamp"
+    (let [mqtt-msg (sut/create-message "{\"test\": \"value\"}" {:qos 2 :retain true})
+          parsed-msg (sut/json-parse-message (sut/parse-message mqtt-msg))]
+      (t/is (= "value" (:test (:payload parsed-msg))))
+      (t/is (instance? java.time.Instant (:timestamp parsed-msg))))))