add test code

ci/app/go_test.go

@@ -0,0 +1,26 @@
+package main
+
+import (
+    "net/http"
+    "net/http/httptest"
+    "strings"
+    "testing"
+)
+
+
+func TestHealthMessage(t *testing.T) {
+    wr := httptest.NewRecorder()
+    req := httptest.NewRequest(http.MethodGet, "/health", nil)
+
+    healthMessage(wr, req)
+    if wr.Code != http.StatusOK {
+        t.Errorf("got HTTP status code %d, expected 200", wr.Code)
+    }
+
+    if !strings.Contains(wr.Body.String(), `{"health":"OK"}`) {
+        t.Errorf(
+            `response body "%s" does not contain "health OK"`,
+            wr.Body.String(),
+        )
+    }
+}

ci/app/main.go

@@ -12,6 +12,11 @@ func indexHandler(w http.ResponseWriter, r *http.Request) {
     w.Write([]byte("<h1>Hello World, im ver:"+Version+" !</h1>"))
 }
 
+func healthMessage(w http.ResponseWriter, r *http.Request) {
+    w.Header().Add("Content-Type", "application/json")
+    w.Write([]byte(`{"health":"OK"}`))
+}
+
 func main() {
     port := os.Getenv("PORT")
     if port == "" {
@@ -22,5 +27,6 @@ func main() {
 
     mux := http.NewServeMux()
     mux.HandleFunc("/", indexHandler)
+    mux.HandleFunc("/health", healthMessage)
     http.ListenAndServe(":"+port, mux)
 }