總之先寫個測試

其實這個測試到底對不對我也不知道XD

這不是單元測試，應該算是功能測試。

基本上就是先準備好一些資料，然後用 `httptest.ResponseRecorder` 發假的
http request，看看它正常情況下回傳的值是不是也很正常。

cmd/xchg/init_test.go

@@ -0,0 +1,40 @@
+package main
+
+import (
+	"database/sql"
+	"log"
+
+	"git.ronmi.tw/ronmi/sdm"
+	_ "github.com/mattn/go-sqlite3"
+)
+
+var (
+	db         *sql.DB
+	mgr        *sdm.Manager
+	presetData []Order
+)
+
+func init() {
+	var err error
+	db, err = sql.Open("sqlite3", ":memory:")
+	if err != nil {
+		log.Fatalf("Cannot connect to database: %s", err)
+	}
+
+	initTable(db)
+	mgr = sdm.New(db)
+
+	presetData = []Order{
+		Order{1468248039, 100, -100, "USD"},
+		Order{1468248040, -50, 51, "USD"},
+		Order{1468248041, 100, -100, "JPY"},
+		Order{1468248042, -50, 51, "JPY"},
+	}
+
+	// create preset data
+	for _, data := range presetData {
+		if _, err := mgr.Insert("orders", data); err != nil {
+			log.Fatalf("Cannot create data %#v: %s", data, err)
+		}
+	}
+}

cmd/xchg/listall_test.go

@@ -0,0 +1,53 @@
+package main
+
+import (
+	"encoding/json"
+	"net/http"
+	"testing"
+
+	"github.com/Patrolavia/jsonapi"
+)
+
+func TestListAll(t *testing.T) {
+	h := &listall{mgr}
+
+	resp, err := jsonapi.HandlerTest(h.Handle).Get("/api/listall", "")
+
+	if err != nil {
+		t.Fatalf("unexpected error occured when testing listall: %s", err)
+	}
+
+	if resp.Code != http.StatusOK {
+		t.Fatalf("unexpected error occured when testing listall with status code %d: %s", resp.Code, resp.Body.String())
+	}
+
+	var orders []Order
+	if resp.Body == nil {
+		t.Fatal(resp)
+	}
+	if err := json.Unmarshal(resp.Body.Bytes(), &orders); err != nil {
+		t.Fatalf("cannot encode returned data from listall: %s", err)
+	}
+
+	// too lazy to use smart algorithm XD
+	if len(orders) != len(presetData) {
+		t.Errorf("listall: expected %d records, got %d", len(presetData), len(orders))
+	}
+
+	counter := make(map[Order]int)
+	for _, data := range presetData {
+		counter[data] = 0
+	}
+
+	for _, o := range orders {
+		cnt, ok := counter[o]
+		if !ok {
+			t.Errorf("listall: unknown order: %#v", o)
+		}
+		if cnt > 0 {
+			t.Errorf("listall: duplicated order: %#v", o)
+		}
+		counter[o] = 1
+	}
+
+}