admin: adds paging to global user list

Currently there is a limit of 1000 users in the global
user list. This change introduces paging so that an
admin can see all users and not just the first 1000.

Adds a new route to the api - /api/users/search that
returns a list of users and a total count. It takes
two parameters perpage and page that enable paging.

Fixes #7469

pkg/api/datasources_test.go

@@ -59,7 +59,9 @@ func loggedInUserScenario(desc string, url string, fn scenarioFunc) {
 	Convey(desc+" "+url, func() {
 		defer bus.ClearBusHandlers()
 
-		sc := &scenarioContext{}
+		sc := &scenarioContext{
+			url: url,
+		}
 		viewsPath, _ := filepath.Abs("../../public/views")
 
 		sc.m = macaron.New()
@@ -71,16 +73,18 @@ func loggedInUserScenario(desc string, url string, fn scenarioFunc) {
 		sc.m.Use(middleware.GetContextHandler())
 		sc.m.Use(middleware.Sessioner(&session.Options{}))
 
-		sc.defaultHandler = func(c *middleware.Context) {
+		sc.defaultHandler = wrap(func(c *middleware.Context) Response {
 			sc.context = c
 			sc.context.UserId = TestUserID
 			sc.context.OrgId = TestOrgID
 			sc.context.OrgRole = models.ROLE_EDITOR
 			if sc.handlerFunc != nil {
-				sc.handlerFunc(sc.context)
+				return sc.handlerFunc(sc.context)
 			}
-		}
-		sc.m.SetAutoHead(true)
+
+			return nil
+		})
+
 		sc.m.Get(url, sc.defaultHandler)
 
 		fn(sc)
@@ -96,6 +100,20 @@ func (sc *scenarioContext) fakeReq(method, url string) *scenarioContext {
 	return sc
 }
 
+func (sc *scenarioContext) fakeReqWithParams(method, url string, queryParams map[string]string) *scenarioContext {
+	sc.resp = httptest.NewRecorder()
+	req, err := http.NewRequest(method, url, nil)
+	q := req.URL.Query()
+	for k, v := range queryParams {
+		q.Add(k, v)
+	}
+	req.URL.RawQuery = q.Encode()
+	So(err, ShouldBeNil)
+	sc.req = req
+
+	return sc
+}
+
 type scenarioContext struct {
 	m              *macaron.Macaron
 	context        *middleware.Context
@@ -103,6 +121,7 @@ type scenarioContext struct {
 	handlerFunc    handlerFunc
 	defaultHandler macaron.Handler
 	req            *http.Request
+	url            string
 }
 
 func (sc *scenarioContext) exec() {
@@ -110,4 +129,4 @@ func (sc *scenarioContext) exec() {
 }
 
 type scenarioFunc func(c *scenarioContext)
-type handlerFunc func(c *middleware.Context)
+type handlerFunc func(c *middleware.Context) Response