Added simple test for monitor-dashboard function

Using clojure.string/includes? to see if the result of calling the
monitor-dashboard function includes specific sub-strings.

This could be done using the mock framework and put into a let to make the code
cleaner.

test/status_monitor/handler_test.clj

@@ -49,3 +49,22 @@
              :fill   "orange"}]]]
       (is (= (component-status-bar 50)
              component-50-per-cent)))))
+
+(deftest test-monitor-dashboard
+  (testing "Test dashboard contains key pieces of information"
+    (is (clojure.string/includes?
+         (monitor-dashboard {})
+         "<title>Area51 Mock Status</title>"))
+    (is (clojure.string/includes?
+         (monitor-dashboard {})
+         "<link href=\"//stackpath.bootstrapcdn.com/bootstrap/4.1.3/css/bootstrap.min.css\" rel=\"stylesheet\" type=\"text/css\">"))
+    (is (clojure.string/includes?
+         (monitor-dashboard {}) "<div class=\"jumbotron\"><h1>Mock Status Monitor Dashboard</h1></div>"))
+    (is (clojure.string/includes?
+         (monitor-dashboard {}) "<h2>Application monitor</h2>"))
+    (is (clojure.string/includes?
+         (monitor-dashboard {})
+         "view-box=\"0 0 100 20\""))))
+
+;; Refactor the above test to use a let value for the response from calling monitor-dashboard
+;; Also consider using the (app (mock/request :get "/")) call in the let and comparing the :body from the response.