[Junit-devel] Using APT as preprocessor for Junit annotations (Patch - 1581916)

[worodin <wo...@fr...>]

Hey ho list!

As a reference for this thread, pls take a look at
https://sourceforge.net/tracker/?func=detail&atid=315278&aid=1581916&group_id=15278
and try the jar.

E. g. executing  a task like

  <exec executable="C:/dev/tool/sun/j2sdk/1.5.0_07/bin/apt.exe">
    <arg line='-classpath ".;./junit4.1/junit-4.1.jar" -nocompile -d "."
org/junit/tests/apt/*.java'/>
  </exec>

against the test classes supplied in the patch would yield:

     [exec] org/junit/tests/apt/AllTests.java:41: The abstract test
class org.junit.tests.apt.TestAfter can not be instanced by suite runner
     [exec] public class AllTests {
     [exec] ^
     [exec] org/junit/tests/apt/AllTests.java:41: The abstract test
class org.junit.tests.apt.TestAfterClass can not be instanced by suite
runner
     [exec] public class AllTests {
     [exec] ^
     [exec] org/junit/tests/apt/AllTests.java:41: The abstract test
class org.junit.tests.apt.TestBefore can not be instanced by suite runner
     [exec] public class AllTests {
     [exec] ^
     [exec] org/junit/tests/apt/AllTests.java:41: The abstract test
class org.junit.tests.apt.TestBeforeClass can not be instanced by suite
runner
     [exec] public class AllTests {
     [exec] ^
     [exec] org/junit/tests/apt/AllTests.java:41: The abstract test
class org.junit.tests.apt.Quiet can not be instanced by suite runner
     [exec] public class AllTests {
     [exec] ^
     [exec] org/junit/tests/apt/EmptySuiteClasses.java:11: warning:
Annotation @SuiteClasses was empty - nothing to test.
     [exec] public class EmptySuiteClasses {}
     [exec] ^
     [exec] org/junit/tests/apt/NoSuiteClasses.java:8: warning: Classes
annotated with @RunWith(Suite.class) should also be annotated with a non
empty @SuiteClasses({}). The resulting test suite is empty.
     [exec] public class NoSuiteClasses {}
     [exec] ^
     [exec] org/junit/tests/apt/NotThrowing.java:7: Checked Exception
org.junit.tests.apt.NotThrowing.MyException will never be thrown,
because it isn't declared for method notThrowing. This test will allways
fail.
     [exec] @Test(expected=MyException.class) public void notThrowing() {}
     [exec] ^
     [exec] org/junit/tests/apt/OrphanedSuite.java:7: warning: The
annotation @SuiteClasses({...}) is only of use for classes also
annotated with @RunWith(Suite.class).
     [exec] public class OrphanedSuite {}
     [exec] ^
     [exec] org/junit/tests/apt/StaticTest.java:7: Methods annotated
with org.junit.Test must not be static.
     [exec] @Test public static void staticTest() {}
     [exec] ^
     [exec] org/junit/tests/apt/TestAfter.java:7: Methods annotated with
org.junit.After need to return void.
     [exec] @After public int notVoid(Object o) {return 0;}
     [exec] ^
     [exec] org/junit/tests/apt/TestAfter.java:7: Methods annotated with
org.junit.After shouldn't have parameters.
     [exec] @After public int notVoid(Object o) {return 0;}
     [exec] ^
     [exec] org/junit/tests/apt/TestAfterClass.java:7: Methods annotated
with org.junit.AfterClass need to be public.
     [exec] @AfterClass void notPublic(Object o) {}
     [exec] ^
     [exec] org/junit/tests/apt/TestAfterClass.java:7: Methods annotated
with org.junit.AfterClass shouldn't have parameters.
     [exec] @AfterClass void notPublic(Object o) {}
     [exec] ^
     [exec] org/junit/tests/apt/TestAfterClass.java:7: Methods annotated
with org.junit.AfterClass need to be static.
     [exec] @AfterClass void notPublic(Object o) {}
     [exec] ^
     [exec] org/junit/tests/apt/TestBefore.java:7: Methods annotated
with org.junit.Before need to be public.
     [exec] @Before int notPublicNotVoid() {return 0;}
     [exec] ^
     [exec] org/junit/tests/apt/TestBefore.java:7: Methods annotated
with org.junit.Before need to return void.
     [exec] @Before int notPublicNotVoid() {return 0;}
     [exec] ^
     [exec] org/junit/tests/apt/TestBeforeClass.java:7: Methods
annotated with org.junit.BeforeClass need to be public.
     [exec] @BeforeClass int notPublicNotVoid(Object o) {return 0;}
     [exec] ^
     [exec] org/junit/tests/apt/TestBeforeClass.java:7: Methods
annotated with org.junit.BeforeClass need to return void.
     [exec] @BeforeClass int notPublicNotVoid(Object o) {return 0;}
     [exec] ^
     [exec] org/junit/tests/apt/TestBeforeClass.java:7: Methods
annotated with org.junit.BeforeClass shouldn't have parameters.
     [exec] @BeforeClass int notPublicNotVoid(Object o) {return 0;}
     [exec] ^
     [exec] org/junit/tests/apt/TestBeforeClass.java:7: Methods
annotated with org.junit.BeforeClass need to be static.
     [exec] @BeforeClass int notPublicNotVoid(Object o) {return 0;}
     [exec] ^
     [exec] org/junit/tests/apt/TestHasParameters.java:7: Methods
annotated with org.junit.Test shouldn't have parameters.
     [exec] @Test public void hasParameters(Object o) {}
     [exec] ^
     [exec] org/junit/tests/apt/TestInheritedParameters.java:11: Methods
annotated with org.junit.runners.Parameterized.Parameters are required
to return java.util.Collection<java.lang.Object[]>.
     [exec] @Parameters public static Object data2() {return new Object();}
     [exec] ^
     [exec] org/junit/tests/apt/TestNotPublic.java:7: Methods annotated
with org.junit.Test need to be public.
     [exec] @Test void notPublic() {}
     [exec] ^
     [exec] org/junit/tests/apt/TestNotVoid.java:7: Methods annotated
with org.junit.Test need to return void.
     [exec] @Test public int notVoid() {return 0;}
     [exec] ^
     [exec]
org/junit/tests/apt/TestParameterizedWith2Constructors.java:15:
Constructor competes with one allready seen at
org/junit/tests/apt/TestParameterizedWith2Constructors.java:14 - classes
annotated with @RunWith(Parameterized.class) require exactly one public
constructor taking the parameters.
     [exec] public TestParameterizedWith2Constructors() {}
     [exec] ^
     [exec]
org/junit/tests/apt/TestParameterizedWith2Constructors.java:12:
org.junit.tests.apt.TestParameterizedWith2Constructors contains 2 public
constructors - classes annotated with @RunWith(Parameterized.class)
require exactly one public constructor taking the parameters.
     [exec] public class TestParameterizedWith2Constructors {
     [exec] ^
     [exec]
org/junit/tests/apt/TestParameterizedWith2ParameterMethods.java:26:
warning: Method annotated with  @Parameters competes with one allready
seen at
org/junit/tests/apt/TestParameterizedWith2ParameterMethods.java:20 - as
of Junit 4.1, only one of them will be used to retrieve test parameters.
     [exec] @Parameters public static Collection<Object[]> data2() {
     [exec] ^
     [exec]
org/junit/tests/apt/TestParameterizedWith2ParameterMethods.java:11:
warning: There are 2 competing methods all annotated with  @Parameters -
as of Junit 4.1, only one of them will be used to retrieve test parameters.
     [exec] public class TestParameterizedWith2ParameterMethods {
     [exec] ^
     [exec]
org/junit/tests/apt/TestParameterizedWithNoParameterMethods.java:9:
Class org.junit.tests.apt.TestParameterizedWithNoParameterMethods is not
abstract, annotated as @RunWith(Parameterized.class), but there is no
instance method annotated with @Parameters within the type hierarchy:
There will be nothing to test.
     [exec] public class TestParameterizedWithNoParameterMethods {
     [exec] ^
     [exec] org/junit/tests/apt/TestParameters.java:11: Methods
annotated with org.junit.runners.Parameterized.Parameters are required
to return java.util.Collection<java.lang.Object[]>.
     [exec] @Parameters public static Object data2() {return new Object();}
     [exec] ^
     [exec] org/junit/tests/apt/SuiteCycle.java:25: The following
classes annotated with @RunWith(Suite.class) form a loop:
org.junit.tests.apt.SuiteCycle.ASuite ->
org.junit.tests.apt.SuiteCycle.AnotherSuite - invoking any of them will
result in a stack overflow at runtime.
     [exec] public static class ASuite {}
     [exec] ^
     [exec] org/junit/tests/apt/SuiteCycle.java:25: Referenced suite
org.junit.tests.apt.SuiteCycle.AnotherSuite is part of or references a
loop of suits - invokation will cause a stack overflow at runtime.
     [exec] public static class ASuite {}
     [exec] ^
     [exec] org/junit/tests/apt/SuiteCycle.java:21: Referenced suite
org.junit.tests.apt.SuiteCycle.ASuite is part of or references a loop of
suits - invokation will cause a stack overflow at runtime.
     [exec] public class SuiteCycle {
     [exec] ^
     [exec] org/junit/tests/apt/AllTests.java:41: Referenced suite
org.junit.tests.apt.SuiteCycle is part of or references a loop of suits
- invokation will cause a stack overflow at runtime.
     [exec] public class AllTests {
     [exec] ^
     [exec] org/junit/tests/apt/NoTestInSuiteClass.java:11: warning:
Test case org.junit.tests.apt.NoTestInSuiteClass doesn't contain any
test methods.
     [exec] public class NoTestInSuiteClass {}
     [exec] ^
     [exec] org/junit/tests/apt/NoSuiteClasses.java:8: warning: Test
case org.junit.tests.apt.NoSuiteClasses doesn't contain any test methods.
     [exec] public class NoSuiteClasses {}
     [exec] ^
     [exec] org/junit/tests/apt/EmptySuiteClasses.java:11: warning: Test
case org.junit.tests.apt.EmptySuiteClasses doesn't contain any test methods.
     [exec] public class EmptySuiteClasses {}
     [exec] ^
     [exec] org/junit/tests/apt/ClassNotPublic.java:9: Class
org.junit.tests.apt.ClassNotPublic has to be public in order to be
instanced.
     [exec] class ClassNotPublic {
     [exec] ^
     [exec] org/junit/tests/apt/NoValidConstructors.java:6: This test
class requires a public no argument constructor.
     [exec] public class NoValidConstructors {
     [exec] ^
     [exec] 32 errors
     [exec] 8 warnings
     [exec] Result: 1


As far as I can tell, the checks are pretty complete, but I'm open to
suggestions. The processor might do with some refactoring, but hey, it's
my first try at apt.

I see several spin offs:

- the apt processor uses 20+ messages (Errors and warnings), some of
them intersecting with runtime messages. It might be viable, to start
pooling all messages used in org.junit in a jdk 1.5 enumeration.

- as an afterthought, I wonder if we really need @RunWith. AFAICT, the
proper runner can mostly infered from an other annotation, e. g.
@SuiteClasses or @Parameters, leaving the rest to the default runner.

- the patch contains a test, that runs apt on a isolated file, checking
for results. This could be evolved into a pattern for testing apt
processors.

Hope this is of interest.

Thomas