JUnit testing with GWT and GAE

[Peerke via StackOverflow]

I want to have some JUnit test (created with GWT) to contact a servlet (with GAE calls inside). When I run the test I get the following stacktrace:

java.lang.NullPointerException
    at com.google.appengine.api.NamespaceManager.get(NamespaceManager.java:101)
    at com.google.appengine.api.memcache.BaseMemcacheServiceImpl.getEffectiveNamespace(BaseMemcacheServiceImpl.java:65)
    at com.google.appengine.api.memcache.AsyncMemcacheServiceImpl.doGet(AsyncMemcacheServiceImpl.java:295)
    at com.google.appengine.api.memcache.AsyncMemcacheServiceImpl.contains(AsyncMemcacheServiceImpl.java:283)
    at com.google.appengine.api.memcache.MemcacheServiceImpl.contains(MemcacheServiceImpl.java:44)
    at com.peerkesoftware.etheria.web.server.model.UpdateTimer.<init>(UpdateTimer.java:17)
    at com.peerkesoftware.etheria.web.server.UpdateTimerServlet.<init>(UpdateTimerServlet.java:12)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
    at java.lang.Class.newInstance0(Class.java:355)
    at java.lang.Class.newInstance(Class.java:308)
    at org.mortbay.jetty.servlet.Holder.newInstance(Holder.java:153)
    at org.mortbay.jetty.servlet.ServletHolder.getServlet(ServletHolder.java:339)
    at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:463)
    at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:362)
    at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
    at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:181)
    at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:729)
    at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:405)
    at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
    at org.mortbay.jetty.handler.RequestLogHandler.handle(RequestLogHandler.java:49)
    at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
    at org.mortbay.jetty.Server.handle(Server.java:324)
    at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:505)
    at org.mortbay.jetty.HttpConnection$RequestHandler.headerComplete(HttpConnection.java:829)
    at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:513)
    at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:211)
    at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:380)
    at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:395)
    at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:488)

Can someone explain to me why this is happening? And how can I resolve this? Do I need to initialize something before running the test?

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http://stackoverflow.com/questions/15573365/junit-testing-with-gwt-and-gae

[SSR via StackOverflow]

The line 101 throwing null pointer exception corresponds to https://code.google.com/p/googleappengine/source/browse/trunk/java/src/main/com/google/appengine/api/NamespaceManager.java

Map<String, Object> attributes =ApiProxy.getCurrentEnvironment().getAttributes();

I am guessing your ApiProxy.getCurrentEnvironment() is returning null.

Solution: Edit war/WEB-INF/web.xml to ApplicationServlet instead of GAEApplicationServlet.

I would like to point out that you unit tests for GWT client side should not be running so deep into server side. You should be using mocking or avoiding server side classes from being invoked from GWT tests to keep the GWT tests faster and client specific.

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http://stackoverflow.com/questions/15573365/junit-testing-with-gwt-and-gae/15607233#15607233

[Peerke via StackOverflow]

I figured it out myself.

The solution that I used: Create LocalServiceTestHelper and set this up before doing any calls to my servlets. Then all my JUnit tests are green.

Please DO NOT REPLY directly to this email but go to StackOverflow:

http://stackoverflow.com/questions/15573365/junit-testing-with-gwt-and-gae/15618140#15618140

[Peerke via StackOverflow]

I'm using GWT version 2.5.1 and GAE version 1.7.5.

My code can be viewed at GitHub.

[step76 via StackOverflow]

The documentation to create JUnit tests for Google App Engine applications under java is here

https://developers.google.com/appengine/docs/java/tools/localunittesting

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http://stackoverflow.com/questions/15573365/junit-testing-with-gwt-and-gae/15657996#15657996