java.lang.Exception: Test class should have exactly one public zero-argument constructor    at org.junit.runners.BlockJUnit4ClassRunner.validateZeroArgConstructor(BlockJUnit4ClassRunner.java:147)    at org.junit.runners.BlockJUnit4ClassRunner.validateConstructor(BlockJUnit4ClassRunner.java:124)    at org.junit.runners.BlockJUnit4ClassRunner.collectInitializationErrors(BlockJUnit4ClassRunner.java:103)    at org.junit.runners.ParentRunner.validate(ParentRunner.java:355)    at org.junit.runners.ParentRunner.<init>(ParentRunner.java:76)    at org.junit.runners.BlockJUnit4ClassRunner.<init>(BlockJUnit4ClassRunner.java:57)    at org.junit.internal.builders.JUnit4Builder.runnerForClass(JUnit4Builder.java:10)    at org.junit.runners.model.RunnerBuilder.safeRunnerForClass(RunnerBuilder.java:59)    at org.junit.internal.builders.AllDefaultPossibilitiesBuilder.runnerForClass(AllDefaultPossibilitiesBuilder.java:26)    at org.junit.runners.model.RunnerBuilder.safeRunnerForClass(RunnerBuilder.java:59)    at org.junit.internal.requests.ClassRequest.getRunner(ClassRequest.java:26)    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.<init>(JUnit4TestReference.java:33)    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestClassReference.<init>(JUnit4TestClassReference.java:25)    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestLoader.createTest(JUnit4TestLoader.java:48)    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestLoader.loadTests(JUnit4TestLoader.java:38)    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:452)    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)