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I have a test class, written in JUnit4 syntax, that can be run in eclipse with the "run as junit test" option without failing. When I run the same test via an ant target I get this error:
java.lang.Exception: Test class should have public zero-argument constructor
at org.junit.internal.runners.MethodValidator.validateNoArgConstructor(MethodValidator.java:54)
at org.junit.internal.runners.MethodValidator.validateAllMethods(MethodValidator.java:39)
at org.junit.internal.runners.TestClassRunner.validate(TestClassRunner.java:33)
at org.junit.internal.runners.TestClassRunner.<init>(TestClassRunner.java:27)
at org.junit.internal.runners.TestClassRunner.<init>(TestClassRunner.java:20)
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 org.junit.internal.requests.ClassRequest.getRunner(ClassRequest.java:26)
at junit.framework.JUnit4TestAdapter.<init>(JUnit4TestAdapter.java:24)
at junit.framework.JUnit4TestAdapter.<init>(JUnit4TestAdapter.java:17)
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 org.apache.tools.ant.taskdefs.optional.junit.JUnitTestRunner.run(JUnitTestRunner.java:386)
at org.apache.tools.ant.taskdefs.optional.junit.JUnitTestRunner.launch(JUnitTestRunner.java:911)
at org.apache.tools.ant.taskdefs.optional.junit.JUnitTestRunner.main(JUnitTestRunner.java:768)
Caused by: java.lang.NoSuchMethodException: dk.gensam.gaia.business.bonusregulering.TestBonusregulerAftale$Test1Reader.<init>()
at java.lang.Class.getConstructor0(Class.java:2706)
at java.lang.Class.getConstructor(Class.java:1657)
at org.junit.internal.runners.MethodValidator.validateNoArgConstructor(MethodValidator.java:52)
I have no public no arg constructor in the class, but is this really necessary?
This is my ant target
<target name="junit" description="Execute unit tests" depends="compile, jar-test">
<delete dir="tmp/rawtestoutput"/>
<delete dir="test-reports"/>
<mkdir dir="tmp/rawtestoutput"/>
<junit printsummary="true" failureproperty="junit.failure" fork="true">
<classpath refid="class.path.test"/>
<classpath refid="class.path.model"/>
<classpath refid="class.path.gui"/>
<classpath refid="class.path.jfreereport"/>
<classpath path="tmp/${test.jar}"></classpath>
<batchtest todir="tmp/rawtestoutput">
<fileset dir="${build}/test">
<include name="**/*Test.class" />
<include name="**/Test*.class" />
</fileset>
</batchtest>
</junit>
<junitreport todir="tmp">
<fileset dir="tmp/rawtestoutput"/>
<report todir="test-reports"/>
</junitreport>
<fail if="junit.
failure" message="Unit test(s) failed. See reports!"/>
</target>
The test class have no constructors, but it has an inner class with default modifier. It also have an anonymouse inner class. Both inner classes gives the "Test class should have public zero-argument constructor error". I am using Ant version 1.7.1 and JUnit 4.7
948
Java doesn't require a constructor when we create a class. However, it's important to know what happens under the hood when no constructors are explicitly defined. The compiler automatically provides a public no-argument constructor for any class without constructors. This is called the default constructor.
In Java, a no-argument constructor is the default constructor and if you don't define explicitly in your program. Then Java Compiler will create a default constructor with no arguments. The purpose is to call the superclass constructor.
Jackson won't use a constructor with arguments by default, you'd need to tell it to do so with the @JsonCreator annotation. By default it tries to use the no-args constructor which isn't present in your class.
So always, remember that JUnit calls the constructor of the test class before executing the test method. You can verify it by putting a System. out. println message in the constructor itself.
I believe you need a no-args constructor, but if you don't declare any constructors Java will create a synthetic one for you. Are you sure the ant-task is not picking up another class; one that just happens to follow the naming convention you've set (*Test or Test*)?
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