I am using Moq, NUnit, WPF, MVVM, Ninject.
I am writing a test for my LoginViewModel, and in the test when I use the constructor of the LoginViewModel to create a new instance, I am getting a NullReferenceException error. The code compiles and runs, (i.e. when I run the program the LoginView shows, and works with the LoginViewModel to create the correct behaviour etc) but for some reason the UnitTest is crashing.
this is the constructor:
public LoginViewModel(ILoginServices loginServices,IDialogService dialogServices)
{
InitializeFields();
_loginServices = loginServices;
_dialogService = dialogServices;
DomainList = _loginServices.GetDomainListing();
}
I have mocked the dependencies as follows:
Mock<ILoginServices> moq = new Mock<ILoginServices>();
moq.Setup(log =>
log.LoginUser(It.IsAny<string>(),
It.IsAny<string>(),
It.IsAny<string>()))
.Callback<string, string, string>((i, j, k) => CheckArgs(i, j, k));
moq.Setup(log2 =>
log2.GetDomainListing()).Returns(new List<string> { "Domain" });
Mock<IDialogService> moq2 = new Mock<IDialogService>();
I have also tried inserting real services as the parameters.
I have verified that the mocks do work, and the objects these mocks
return are not null.
I have commented out all the code in the constructor.
I have tried inserting the line
LoginViewModel test = new LoginViewModel(_fakeLoginService,_fakeDialogService);
in front of the call to the constructor (to see if it had to do with the original local variable being disposed or something before) and this line crashed instead.
From all I can see this must be the constructor,(but not the code I have written inside it) and that this is solely related to NUnit / Moq as my code still compiles and runs fine.
I have no idea on this one guys, can anyone point me in the right direction?
[Edit]
Ok so I have run through the code and the error comes from this line of code:
ImageSource = (ImageSource)Application.Current.FindResource(_imageName);
This code is going to a ImageDictionary and getting a reference to the image for an undo button in the WindowViewModel (which my LoginViewModel inherits).
My hypotheses as to why its working in the normal running of the application, but not in the testing are:
1) Because I am running the program code through NUnit, the Application.Current object isnt getting property assigned/there is no Application.Current object to get.
**or**
2) Something to do with the fact that because the program code is being run in NUnit, the code doesn't have access to/can't resolve the ImageDictionary to find the image.
I'm leaning more strongly to the first hypothesis, but I'm as of yet not 100% sure, and I am having trouble finding the values of the Application.Current at runtime, cause when I move my cursor over the code the tooltip that normally appears showing the detail of the object that is not appearing.
My new question is: Does any of this make sense? Do you guys know if the Application.Current object exists / can be accessed when running the testing project through NUnit?
Any help will be appreciated.
You are correct. Application.Current is null for Unit tests. You can work around this by injecting the Application object as referencing singletons in code can make life tricky.
Related
I have ~50 JSON arrays as an array of models being plugged into Unit tests to compare resultant configs. Each file looks like this:
0.json
1.json... and so on
[{model1},{model2},{model3}]
I am trying to run unit tests to compare the resultant configs and want to run the tests in a manner that the test itself keeps running and collect the models if an assertion fails and output it to a json file somewhere.
Say, model2 fails, I want to collect model2 into a file output.json as an array
Till now, the code looks like this, even if the test is file by file, its fine, but will save me days of effort:
#Test
public void compareAWithB() throws Exception {
File lbJsonFile1 = new File("src/test/resources/iad_ad3/6.json");
compareAWithBHelper(lbJsonFile1);
}
public void compareAWithBHelper(File lbJsonFile) throws Exception {
Model[] dtos = new ObjectMapper().readValue(lbJsonFile, Model[].class);
for(Model dto : dtos) {
Model model = ModelConverter.apiToDao(dto);
String A = doSomeThing();
String B = doSomething2();
Assert.assertEquals(A,B);
//Required: if assert fails, collect the json object and continue
}
I tried using SoftAssertions in AssertJ, but weirdly, it was not printing out all the json objects OR maybe, I don't really understand the checkThat() method properly.
Tried using collectors.checkThat, couldn't get it to work reliably. This is a production area, so, don't have much room for errors, and wanna reduce the manual effort.
Made another attempt to use collectors as one of the posts on stackoverflow, couldn't get it to work reliably
/*try {
collector.checkThat(A, CoreMatchers.equalTo(B));
} catch (AssertionError error) {
System.out.println(dto.toString());
throw new AssertionError(error.getMessage());
}*/
Can someone please help ?
If you want to gather all assertion errors and not stop at the first error then soft assertions is a good candidate to use. To get started with soft assertions you can follow the guide available here: https://assertj.github.io/doc/#assertj-core-soft-assertions.
collector.checkThat does not come from AssertJ (neither anything from your code samples), it's a bit confusing, I would suggest to write a reproducible test so that people can help more easily.
Alternatively if you are dealing with JSON, you can give a try to addressed by https://github.com/lukas-krecan/JsonUnit which provides first class citizen JSON assertions.
Hope it helps.
Using Flash CC
I have the following array. The first key retrieves the string "Fish" from another array.
static public var comboType_1:Array =
[Constants.level_Data_Edible[Constants.currentLevel],"Frog"];
When I try to iterate over this array with
for(var i:String in hint)
trace(hint[i]);
I get this result:
Fish,
Frog,
function Function() {}
I debug it, it shows the array length is 2.
I googled the function Function() {} and it produces zero hits on Google.
No one has ever heard of this function Function() {} error.
There is no third index, you can see in the array. This error prevents me from iterating over the array. #1065. Variable Function function () {} is not defined.
I'm pretty sure this is yet another Flash bug, but I just want to know the workaround.
Look it is clear that you have discovered how useful static variables can be and you use them as global variables all over your app but since you do not understand when those static variables are instantiated you are running into troubles. If you prefer to blame everything on the technology itself suit yourself but that won't fix your problem and won't make you a better coder. static variables are instantiated prior to anything else in your app so for example using another static variable like that one:
Constants.currentLevel
Is likely to produce error cos whatever the currentLevel is will be ignored anyway. Anything labelled 'current' is a red flag when instantiating static variables cos when static variables are created there's nothing current going on.
The result you are getting and the code you are showing do not match and you only do that on purpose to prove your point. You could show the whole code but you won't cos you know very well that the true mistake (your own code) will be pointed out.
Stop feeling sorry for yourself, stop blaming anything but yourself and post a real question with real code so we can show you where your mistake is.
I have just started a new version of my Crysis Wars Server Side Modification called InfinityX. For better management, I have put the functions inside tables as it looks neater and I can group functions together (like Core.PlayerHandle:GetIp(player)), but I have ran into a problem.
The problem is that the specified method to get the players' name, player:GetName() is being seen as an invalid method, when the method actually is completely valid.
I would like to know if using the below structure is causing a problem and if so, how to fix it. This is the first time I've used this structure for functions, but it is already proving easier than the old method I was using.
The Code:
Event =
{
PlayerConnect = function(player)
Msg.All:CenteredConsole("$4Event$8 (Connect)$9: $3"..player:GetName().." on channel "..player.actor:GetChannel());
System.LogAlways(Default.Tag.."Incoming Connect on Channel "..player.actor:GetChannel());
Event:Log("Connect", player);
end;
};
The below code works when I bypass the function and put the code directly where it's needed:
Msg.All:CenteredConsole("$4Event$8 (Connect)$9: $3"..player:GetName().." on channel "..player.actor:GetChannel());
System.LogAlways(Default.Tag.."Incoming Connect on Channel "..player.actor:GetChannel());
The Error:
[Warning] [Lua Error] infinityx/main/core.events.lua:23: attempt to call method 'GetName' (a nil value)
PlayerConnect, (infinityx/main/core.events.lua: 23)
ConnectScript, (infinityx/main/core.main.lua: 52)
OnClientEnteredGame, (scripts/gamerules/instantaction.lua: 511)
(null) (scripts/gamerules/teaminstantaction.lua: 520)
Any clarification would be appreciated.
Thanks :)
Well, as PlayerConnect is inside the table Event, and you are calling with a ":", add self as first arg in the function, like:
PlayerConnect = function(self, player)
Clearly, player in the first block of code is not the same as player in the second block of code. The problem must be that the caller of Event.PlayerConnect is not passing the same value.
To test that your Event.PlayerConnect function works, try this in the same place as your second block of code:
Event.PlayerConnect(player)
That should work as you expect.
So, the problem comes down to how Event.PlayerConnect is called without the second block of code. I'm not familiar with that game engine so I don't know how it is done. Perhaps reviewing the documentation and/or debugging that area would help. If you print(player) or call the equivalent log function in both cases, you should see they are different. If you can't run in a debugger, you can still get a stack trace with print(debug.traceback("Accessing player, who's value is: "..player)). If there is indeed some kind of table-based player object in both cases, you can try comparing their fields to see how they are different. You might need to write a simple dumping function to help with that.
I am extremely frustrated. I'm following a tutorial and mimicing it on my own. I have been able to sort out most of the errors so far but this one has me stumped. I have tried replacing all of the class files with the tutorial specimen ones but i still get the error.
TypeError: Error #1009: Cannot access a property or method of a null object reference.
at com.senocular.utils::KeyObject/construct()
at com.senocular.utils::KeyObject()
at com.asgamer.basics1::Ship()
at com.asgamer.basics1::Engine()
Now, not really understanding the error properly I paste dumped the files online for you to look at.
Ship class: textbin.com/78z35
Engine class: textbin.com/32b24
KeyObject class: textbin.com/p2725
As the error still occured when using the specimen class files I really have no idea where to begin. I will gladly try out any suggestions.
Tip: If you allow debugging, the exception will tell you the exact line in the source code where the Error is being thrown. Assuming you're using the Flash IDE, go to publish settings and in the Flash tab check "Permit debugging". This will makes thing much easier for you.
Anyway, you have an error message. If you read it carefully, you can narrow down where the problem is. I don't know if you are a programmer or you have any interest in being one; if you're not, this answer will hopefully solve this particular problem. Anyway, if you don't mind the rambling, let me tell you that if you're interested in becoming a better programmer, paying attention to errors and learning how to debug / troubleshoot problems is one of the most important abilities you need to develop (if not the most important one); so maybe this will give you a few hints you can use to solve other problems as well.
The message says:
Cannot access a property or method of
a null object reference.
This means, at some point, you did something like this:
someobject.someMethod();
or
someobject.someProperty = "foo";
And someobject happened to be null. You can't call methods or access properties of null.
Ok, so now you know, somewhere, a variable had null as its value. Notice that the fact that you define a variable of property doesn't mean it actually holds an object.
This just says that a variable called mySprite can hold an object of the type Sprite:
var mySprite:Sprite;
But until at some point you create a Sprite and assign it to mySprite, the value held by mySprite will be null. If you do:
mySprite.x = 0;
Before initializing mySprite (i.e. before assigning a Sprite to it), you will have this same Null Reference error.
This error message also offers some helpul context, which you can use to your advantage (in them old days... errors in Flash were silent; when things didn't work, you had to manually trace down the problem).
Ok, let's break this error message down:
at com.senocular.utils::KeyObject/construct()
at com.senocular.utils::KeyObject()
at com.asgamer.basics1::Ship()
at com.asgamer.basics1::Engine()
What you have above is called a stack trace. It basically tells you where the code blew up, and also gives you some context: how did you get there.
The first line tells where the error actually occurred. That is, the construct method in the KeyObject object. That method was called from the KeyObject constructor, which was in turn called from the Ship constructor, which was in turn called from the Engine constructor.
Now, let's analyze how you got there, following the stack trace, bottom-up:
Code in Engine constructor:
ourShip = new Ship(stage);
This creates a new Ship object. It passes a reference to the stage to the Ship constructor method.
Code in Ship constructor:
this.stageRef = stageRef;
key = new KeyObject(stageRef);
It grabs the ref passed in the previous step. It stores it and creates a new KeyObject object. The KeyObject constructor is passed a reference to the stage (which is the same ref that was passed from Engine to Ship).
Code in KeyObject constructor:
KeyObject.stage = stage;
keysDown = new Object();
stage.addEventListener(KeyboardEvent.KEY_DOWN, keyPressed);
stage.addEventListener(KeyboardEvent.KEY_UP, keyReleased);
Now we got to the point where the error message told you the problem was. So, somewhere, you are using a variable that holds null and trying to access one of its methods or properties.
This KeyObject stores the reference to stage it was passed in a static variable and creates a new Object object. So far, no problems. KeyObject cannot be null (it's a reference to a Class). The second line itself cannot have this null problem either. So, if this is all the code in that method, the problem has to be either in the third or the fourth line. Both access the stage reference you passed and try to call a method (addEventListener) on it. So if one fails, the other will fail as well. Then, the third line: that's where the problem has to be.
So, at that point stage is null. As said previously, you can't call a method on null, and that's what the error is telling you.
Now, if you get back to the first method call, you can see this is the origin of the problem:
ourShip = new Ship(stage);
You can be pretty sure that, at this point, stage was null. Add that to the fact that Engine extends MovieClip (which is in turn a DisplayObject), and to the fact that any DisplayObject has a reference to the stage object only while it's added to the display list. The conclusion: an instance of Engine was not attached to the display list when its constructor was ran.
A way to fix this (there might be others) could be moving the code in the Engine constructor to a separate function that will be executed only if / when the Engine object has a valid reference to the stage object.
public function Engine() : void {
if(stage) {
initialize();
} else {
addEventListener(Event.ADDED_TO_STAGE,initialize);
}
}
private function initialize(e:Event = null):void {
removeEventListener(Event.ADDED_TO_STAGE,initialize);
// here goes the code that's currently in Engine constructor
}
Hope this helps.
I have a feeling your stage property is null.
You have have to test this yourself with a trace of the stage object.
In the first line in the constructor of you Engine class, add:
trace(stage);
Add that just above this line:
ourShip = new Ship(stage);
If it traces "null" then that is your problem.
I'm trying to setup a test in JUnit w/ EasyMock and I'm running into a small issue that I can't seem to wrap my head around. I was hoping someone here could help.
Here is a simplified version of the method I'm trying to test:
public void myMethod() {
//(...)
Obj myObj = this.service.getObj(param);
if (myObj.getExtId() != null) {
OtherObj otherObj = new OtherObj();
otherObj.setId(myObj.getExtId());
this.dao.insert(otherObj);
}
//(...)
}
Ok so using EasyMock I've mocked the service.getObj(myObj) call and that works fine.
My problem comes when JUnit hits the dao.insert(otherObj) call. EasyMock throws a *Unexpected Method Call* on it.
I wouldn't mind mocking that dao in my test and using expectLastCall().once(); on it, but that assumes that I have a handle on the "otherObj" that's passed as a parameter at insert time...
Which of course I don't since it's conditionally created within the context of the method being tested.
Anyone has ever had to deal with that and somehow solved it?
Thanks.
You could also use EasyMock.isA(OtherObj.class) for a little more type safety.
If you can't get a reference to the object itself in your test code, you could use EasyMock.anyObject() as the expected argument to yourinsert method. As the name suggests, it will expect the method to be called with.. well, any object :)
It's maybe a little less rigorous than matching the exact argument, but if you're happy with it, give it a spin. Remember to include the cast to OtherObjwhen declaring the expected method call.
The anyObject() matcher works great if you just want to get past this call, but if you actually want to validate the constructed object is what you thought it was going to be, you can use a Capture. It would look something like:
Capture<OtherObj> capturedOtherObj = new Capture<OtherObj>();
mockDao.insert(capture(capturedOtherObj));
replay(mockDao);
objUnderTest.myMethod();
assertThat("captured what you expected", capturedOtherObj.getValue().getId(),
equalTo(expectedId));
Also, PowerMock has the ability to expect an object to be constructed, so you could look into that if you wanted.
Note also that if you use EasyMock.createStrictMock();, the order of the method calls is also important and if you break this rule, it would throw an unexpected method call.