新浪微博客户端围脖七开发笔记（2） 添加更多测试到MainPageViewModel
想了一个礼拜，究竟是先实现些具体功能呢，还是继续完善TDD，还是先后者吧：具体功能无非就是些api的调用，wp7的twiter或者围脖的例子也有一些了，也不少我这一篇:)
1. 准备几个基本类，status，user和SinaService接口
代码
public
class
User
{
public
ulong
Id {
get
;
set
; }
public
string
ScreenName {
get
;
set
; }
public
string
ImageUrl {
get
;
set
; }
public
string
Name {
get
;
set
; }
public
string
Url {
get
;
set
; }
public
string
Description {
get
;
set
; }
public
string
Location {
get
;
set
; }
public
int
Followers {
get
;
set
; }
public
int
Friends {
get
;
set
; }
public
DateTime CreatedAt {
get
;
set
; }
}
public
class
Status
{
public
Status()
{
User
=
new
User();
}
public
DateTime CreatedAt {
get
;
set
; }
public
ulong
Id {
get
;
set
; }
public
string
Text {
get
;
set
; }
public
string
Source {
get
;
set
; }
public
User User {
get
;
set
; }
public
bool
Favorited {
get
;
set
; }
public
int
RetweetCount {
get
;
set
; }
public
bool
Retweeted {
get
;
set
; }
}
///
<summary>
///
A simple Sina service interface
///
</summary>
public
interface
ISinaService
{
///
<summary>
///
Get statuses from sina weibo
///
</summary>
///
<param name="onGetStatusesCompleted">
the callback method
</param>
///
<param name="onError"></param>
///
<param name="onFinally"></param>
void
GetStatuses(Action
<
IEnumerable
<
Status
>>
onGetStatusesCompleted
=
null
, Action
<
Exception
>
onError
=
null
, Action onFinally
=
null
);
}
status和user类的相应测试俺就偷懒不写了，读者有兴趣可以自己试试！
2. 修改下MainPageViewModel， 加入SinaService接口和HomeList，前者用来调用sina的接口取得数据，后者是最新微博的容器。注意把它们设置为internal，方便测试项目调用，还要添加如下一行在AssemblyInfo.cs中：
[assembly: InternalsVisibleTo("WeiBo7.Test")]
代码
public
class
MainPageViewModel : ViewModelBase
{
internal
readonly
ISinaService SinaService;
private
bool
_isHomeRefreshing
=
false
;
public
MainPageViewModel()
{
SinaService
=
new
SinaService();
HomeList
=
new
ObservableCollection
<
Status
>
();
}
public
ObservableCollection
<
Status
>
HomeList {
get
;
internal
set
; }
///
<summary>
///
Indicates whether there is an indeterminate operation in progress
///
</summary>
public
bool
IsHomeRefreshing
{
get
{
return
_isHomeRefreshing; }
set
{
if
(value
!=
_isHomeRefreshing)
{
_isHomeRefreshing
=
value;
OnNotifyPropertyChanged(
"
IsHomeRefreshing
"
);
}
}
}
}
3. 现在转到测试项目，先加入一个TestInitialize方法，在所有的测试方法前做些准备工作：
private
MainPageViewModel _mainViewModel;
[TestInitialize]
public
void
Initialize()
{
_mainViewModel
=
new
MainPageViewModel();
}
还可以加入一个[TestCleanup]方法：
[TestCleanup]
public
void
CleanUp()
{
}
目前没干什么事情，但对于任何一个测试方法，执行顺序是TestInitialize->test method->TestCleanup, 这样保证每个测试方法是彼此独立，互不影响，不用在每个测试方法里面都初始化，节省些代码。
4. 在MainPageViewModelTests先添加一个negative test, 看下这个类如何应对NullInstance
代码
[TestMethod]
[ExpectedException(
typeof
(NullReferenceException))]
public
void
NullInstance()
{
_mainViewModel
=
null
;
bool
x
=
_mainViewModel.IsHomeRefreshing;
}
5. 测试初始化是否成功
代码
[TestMethod]
public
void
Init_MainPageViewModel_Success()
{
Assert.IsNotNull(_mainViewModel);
Assert.IsNotNull(_mainViewModel.HomeList);
Assert.IsNotNull(_mainViewModel.SinaService);
Assert.IsInstanceOfType(_mainViewModel,
typeof
(INotifyPropertyChanged));
}
6. 测试当添加一个item到HomeList时，是否CollectionChanged被fire
代码
[TestMethod]
public
void
AddItem_HomeList_RaisesCollectionChanged()
{
bool
changeObserved
=
false
;
_mainViewModel.HomeList.CollectionChanged
+=
(s, e)
=>
{
changeObserved
=
true
;
Assert.AreEqual(NotifyCollectionChangedAction.Add, e.Action);
Assert.AreEqual(
1
, e.NewItems.Count,
"
only should be +1 item
"
);
};
_mainViewModel.HomeList.Add(
new
Status());
Assert.IsTrue(changeObserved);
}
