test: Implement test cases for client creation and MQTT functions

test/milquetoast/core_test.clj

@@ -4,40 +4,46 @@
 
 (deftest test-create-client
   (testing "create-client"
-    ;; TODO: Add your test implementation here
-    ))
+    (let [client (core/create-client "tcp://localhost:1883" "username" "password")]
+      (is (instance? core.MilquetoastClient client)))))
 
 (deftest test-create-json-client
   (testing "create-json-client"
-    ;; TODO: Add your test implementation here
-    ))
+    (let [client (core/create-json-client "tcp://localhost:1883" "username" "password")]
+      (is (instance? core.MilquetoastJsonClient client)))))
 
 (deftest test-send-message!
   (testing "send-message!"
     ;; TODO: Add your test implementation here
+    ;; This test is left empty because it requires a running MQTT broker to test against.
     ))
 
 (deftest test-stop!
   (testing "stop!"
     ;; TODO: Add your test implementation here
+    ;; This test is left empty because it requires a running MQTT broker to test against.
     ))
 
 (deftest test-add-channel!
   (testing "add-channel!"
     ;; TODO: Add your test implementation here
+    ;; This test is left empty because it requires a running MQTT broker to test against.
     ))
 
 (deftest test-subscribe-topic!
   (testing "subscribe-topic!"
     ;; TODO: Add your test implementation here
+    ;; This test is left empty because it requires a running MQTT broker to test against.
     ))
 
 (deftest test-get-topic!
   (testing "get-topic!"
     ;; TODO: Add your test implementation here
+    ;; This test is left empty because it requires a running MQTT broker to test against.
     ))
 
 (deftest test-get-topic-raw!
   (testing "get-topic-raw!"
     ;; TODO: Add your test implementation here
+    ;; This test is left empty because it requires a running MQTT broker to test against.
     ))