我试图按照这篇博客的描述，在Eclipse中使用Robolectric运行一个App的测试用例，但是当我运行JUnit测试时，出现了以下错误：
java.lang.RuntimeException: java.io.FileNotFoundException: C:\Users\abc\workspace\SumTestCases\AndroidManifest.xml not found or not a file; it should point to your project's AndroidManifest.xml
at com.xtremelabs.robolectric.RobolectricTestRunner.createResourceLoader(RobolectricTestRunner.java:269)
at com.xtremelabs.robolectric.RobolectricTestRunner.setupApplicationState(RobolectricTestRunner.java:229)
at com.xtremelabs.robolectric.RobolectricTestRunner.internalBeforeTest(RobolectricTestRunner.java:177)
at com.xtremelabs.robolectric.RobolectricTestRunner.methodBlock(RobolectricTestRunner.java:157)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:68)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:47)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:231)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:60)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:229)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:50)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:222)
at org.junit.runners.ParentRunner.run(ParentRunner.java:300)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50)
at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)
Caused by: java.io.FileNotFoundException: C:\Users\abc\workspace\SumTestCases\AndroidManifest.xml not found or not a file; it should point to your project's AndroidManifest.xml
at com.xtremelabs.robolectric.RobolectricTestRunner.createResourceLoader(RobolectricTestRunner.java:256)
... 17 more
我错在哪里了？