Advertise lambdas as arguments to then / runRemotely

src/main/java/org/jvnet/hudson/test/RealJenkinsRule.java

@@ -745,9 +745,8 @@ public String[] getTruststoreJavaOptions() {
     /**
      * One step to run.
      * <p>Since this thunk will be sent to a different JVM, it must be serializable.
-     * The test class will certainly not be serializable, so you cannot use an anonymous inner class,
-     * and regular lambdas also risk accidentally capturing non-serializable objects from scope.
-     * The friendliest idiom is a static method reference:
+     * The test class will certainly not be serializable, so you cannot use an anonymous inner class.
+     * One idiom is a static method reference:
      * <pre>
      * &#64;Test public void stuff() throws Throwable {
      *     rr.then(YourTest::_stuff);
@@ -759,6 +758,17 @@ public String[] getTruststoreJavaOptions() {
      * If you need to pass and/or return values, you can still use a static method reference:
      * try {@link #runRemotely(Step2)} or {@link #runRemotely(StepWithReturnAndOneArg, Serializable)} etc.
      * (using {@link XStreamSerializable} as needed).
+     * <p>
+     * Alternately, you could use a lambda:
+     * <pre>
+     * &#64;Test public void stuff() throws Throwable {
+     *     rr.then(r -> {
+     *         // as needed
+     *     });
+     * }
+     * </pre>
+     * In this case you must take care not to capture non-serializable objects from scope;
+     * in particular, the body must not use (named or anonymous) inner classes.
      */
     @FunctionalInterface
     public interface Step extends Serializable {

src/main/java/org/jvnet/hudson/test/TestBuilder.java

@@ -58,4 +58,23 @@ public boolean isApplicable(Class<? extends AbstractProject> jobType) {
     }
 
     protected Object writeReplace() { return new Object(); }
+
+    @FunctionalInterface
+    public interface Body {
+        void perform(AbstractBuild<?, ?> build, Launcher launcher, BuildListener listener) throws InterruptedException, IOException;
+    }
+
+    /**
+     * More convenient form that can be used with a lambda.
+     */
+    public static Builder of(Body body) {
+        return new TestBuilder() {
+            @Override
+            public boolean perform(AbstractBuild<?, ?> build, Launcher launcher, BuildListener listener) throws InterruptedException, IOException {
+                body.perform(build, launcher, listener);
+                return true;
+            }
+        };
+    }
+
 }

src/test/java/org/jvnet/hudson/test/RealJenkinsRuleTest.java

@@ -65,7 +65,7 @@
 import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.util.List;
-import java.util.concurrent.atomic.AtomicReference;
+import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.logging.Level;
 import javax.servlet.Filter;
 import javax.servlet.FilterChain;
@@ -77,6 +77,7 @@
 import jenkins.model.JenkinsLocationConfiguration;
 import static org.junit.Assume.assumeThat;
 import org.junit.AssumptionViolatedException;
+import org.junit.Ignore;
 import org.junit.Rule;
 import org.junit.Test;
 import org.jvnet.hudson.test.recipes.LocalData;
@@ -180,41 +181,33 @@ private static void _error(JenkinsRule r) throws Throwable {
     }
 
     @Test public void agentBuild() throws Throwable {
-        try (TailLog tailLog = new TailLog(rr, "p", 1).withColor(PrefixedOutputStream.Color.MAGENTA)) {
-            rr.then(RealJenkinsRuleTest::_agentBuild);
+        try (var tailLog = new TailLog(rr, "p", 1).withColor(PrefixedOutputStream.Color.MAGENTA)) {
+            rr.then(r -> {
+                var p = r.createFreeStyleProject("p");
+                var ran = new AtomicBoolean();
+                p.getBuildersList().add(TestBuilder.of((build, launcher, listener) -> ran.set(true)));
+                p.setAssignedNode(r.createOnlineSlave());
+                r.buildAndAssertSuccess(p);
+                assertTrue(ran.get());
+            });
             tailLog.waitForCompletion();
         }
     }
-    private static void _agentBuild(JenkinsRule r) throws Throwable {
-        FreeStyleProject p = r.createFreeStyleProject("p");
-        AtomicReference<Boolean> ran = new AtomicReference<>(false);
-        p.getBuildersList().add(new TestBuilder() {
-            @Override public boolean perform(AbstractBuild<?, ?> build, Launcher launcher, BuildListener listener) throws InterruptedException, IOException {
-                ran.set(true);
-                return true;
-            }
-        });
-        p.setAssignedNode(r.createOnlineSlave());
-        r.buildAndAssertSuccess(p);
-        assertTrue(ran.get());
-    }
 
     @Test public void htmlUnit() throws Throwable {
         rr.startJenkins();
-        rr.runRemotely(RealJenkinsRuleTest::_htmlUnit1);
+        rr.runRemotely(r -> {
+            r.jenkins.setSecurityRealm(r.createDummySecurityRealm());
+            r.jenkins.setAuthorizationStrategy(new MockAuthorizationStrategy().grant(Jenkins.ADMINISTER).everywhere().to("admin"));
+            var p = r.createFreeStyleProject("p");
+            p.setDescription("hello");
+        });
         System.err.println("running against " + rr.getUrl());
-        rr.runRemotely(RealJenkinsRuleTest::_htmlUnit2);
-    }
-    private static void _htmlUnit1(JenkinsRule r) throws Throwable {
-        r.jenkins.setSecurityRealm(r.createDummySecurityRealm());
-        r.jenkins.setAuthorizationStrategy(new MockAuthorizationStrategy().grant(Jenkins.ADMINISTER).everywhere().to("admin"));
-        FreeStyleProject p = r.createFreeStyleProject("p");
-        p.setDescription("hello");
-    }
-    private static void _htmlUnit2(JenkinsRule r) throws Throwable {
-        FreeStyleProject p = r.jenkins.getItemByFullName("p", FreeStyleProject.class);
-        r.submit(r.createWebClient().login("admin").getPage(p, "configure").getFormByName("config"));
-        assertEquals("hello", p.getDescription());
+        rr.runRemotely(r -> {
+            var p = r.jenkins.getItemByFullName("p", FreeStyleProject.class);
+            r.submit(r.createWebClient().login("admin").getPage(p, "configure").getFormByName("config"));
+            assertEquals("hello", p.getDescription());
+        });
     }
 
     private static String _getJenkinsUrlFromRemote(JenkinsRule r) {
@@ -230,18 +223,16 @@ private static void _localData(JenkinsRule r) throws Throwable {
     }
 
     @Test public void restart() throws Throwable {
-        rr.then(RealJenkinsRuleTest::_restart1);
-        rr.then(RealJenkinsRuleTest::_restart2);
-    }
-    private static void _restart1(JenkinsRule r) throws Throwable {
-        assertEquals(r.jenkins.getRootUrl(), r.getURL().toString());
-        Files.writeString(r.jenkins.getRootDir().toPath().resolve("url.txt"), r.getURL().toString(), StandardCharsets.UTF_8);
-        r.jenkins.getExtensionList(ItemListener.class).add(0, new ShutdownListener());
-    }
-    private static void _restart2(JenkinsRule r) throws Throwable {
-        assertEquals(r.jenkins.getRootUrl(), r.getURL().toString());
-        assertEquals(r.jenkins.getRootUrl(), Files.readString(r.jenkins.getRootDir().toPath().resolve("url.txt"), StandardCharsets.UTF_8));
-        assertTrue(new File(Jenkins.get().getRootDir(), "RealJenkinsRule-ran-cleanUp").exists());
+        rr.then(r -> {
+            assertEquals(r.jenkins.getRootUrl(), r.getURL().toString());
+            Files.writeString(r.jenkins.getRootDir().toPath().resolve("url.txt"), r.getURL().toString(), StandardCharsets.UTF_8);
+            r.jenkins.getExtensionList(ItemListener.class).add(0, new ShutdownListener());
+        });
+        rr.then(r -> {
+            assertEquals(r.jenkins.getRootUrl(), r.getURL().toString());
+            assertEquals(r.jenkins.getRootUrl(), Files.readString(r.jenkins.getRootDir().toPath().resolve("url.txt"), StandardCharsets.UTF_8));
+            assertTrue(new File(Jenkins.get().getRootDir(), "RealJenkinsRule-ran-cleanUp").exists());
+        });
     }
     private static class ShutdownListener extends ItemListener {
         private final String fileName = "RealJenkinsRule-ran-cleanUp";
@@ -263,15 +254,13 @@ private static void _stepsDoNotRunOnHttpWorkerThread(JenkinsRule r) throws Throw
     }
 
     @Test public void stepsDoNotOverwriteJenkinsLocationConfigurationIfOtherwiseSet() throws Throwable {
-        rr.then(RealJenkinsRuleTest::_stepsDoNotOverwriteJenkinsLocationConfigurationIfOtherwiseSet1);
-        rr.then(RealJenkinsRuleTest::_stepsDoNotOverwriteJenkinsLocationConfigurationIfOtherwiseSet2);
-    }
-    private static void _stepsDoNotOverwriteJenkinsLocationConfigurationIfOtherwiseSet1(JenkinsRule r) throws Throwable {
-        assertNotNull(JenkinsLocationConfiguration.get().getUrl());
-        JenkinsLocationConfiguration.get().setUrl("https://example.com/");
-    }
-    private static void _stepsDoNotOverwriteJenkinsLocationConfigurationIfOtherwiseSet2(JenkinsRule r) throws Throwable {
-        assertEquals("https://example.com/", JenkinsLocationConfiguration.get().getUrl());
+        rr.then(r -> {
+            assertNotNull(JenkinsLocationConfiguration.get().getUrl());
+            JenkinsLocationConfiguration.get().setUrl("https://example.com/");
+        });
+        rr.then(r -> {
+            assertEquals("https://example.com/", JenkinsLocationConfiguration.get().getUrl());
+        });
     }
 
     @Test
@@ -378,35 +367,46 @@ private static void _noDetachedPlugins(JenkinsRule r) throws Throwable {
 
     @Test
     public void safeExit() throws Throwable {
-        rr.then(RealJenkinsRuleTest::_safeExit);
-    }
-
-    private static void _safeExit(JenkinsRule r) throws Throwable {
-        var p = r.createFreeStyleProject();
-        p.getBuildersList().add(new TestBuilder() {
-            @Override
-            public boolean perform(AbstractBuild<?, ?> build, Launcher launcher, BuildListener listener) throws InterruptedException, IOException {
-                Thread.sleep(Long.MAX_VALUE);
-                return false;
-            }
+        rr.then(r -> {
+            var p = r.createFreeStyleProject();
+            p.getBuildersList().add(TestBuilder.of((build, launcher, listener) -> Thread.sleep(Long.MAX_VALUE)));
+            p.scheduleBuild2(0).waitForStart();
         });
-        p.scheduleBuild2(0).waitForStart();
     }
 
     @Test public void xStreamSerializable() throws Throwable {
         rr.startJenkins();
         // Neither ParametersDefinitionProperty nor ParametersAction could be passed directly.
         // (In this case, ParameterDefinition and ParameterValue could have been used raw.
         // But even List<ParameterValue> cannot be typed here, only e.g. ArrayList<ParameterValue>.)
-        var a = rr.runRemotely(RealJenkinsRuleTest::_xStreamSerializable, XStreamSerializable.of(new ParametersDefinitionProperty(new StringParameterDefinition("X", "dflt"))));
-        assertThat(a.object().getAllParameters(), hasSize(1));
-    }
-
-    private static XStreamSerializable<ParametersAction> _xStreamSerializable(JenkinsRule r, XStreamSerializable<JobProperty<? super FreeStyleProject>> prop) throws Throwable {
+        var prop = XStreamSerializable.of(new ParametersDefinitionProperty(new StringParameterDefinition("X", "dflt")));
+        // Static method handle idiom:
+        assertThat(rr.runRemotely(RealJenkinsRuleTest::_xStreamSerializable, prop).object().getAllParameters(), hasSize(1));
+        // Lambda idiom:
+        assertThat(rr.runRemotely(r -> {
+            var p = r.createFreeStyleProject();
+            p.addProperty(prop.object());
+            var b = r.buildAndAssertSuccess(p);
+            return XStreamSerializable.of(b.getAction(ParametersAction.class));
+        }).object().getAllParameters(), hasSize(1));
+    }
+
+    private static XStreamSerializable<ParametersAction> _xStreamSerializable(JenkinsRule r, XStreamSerializable<? extends JobProperty<? super FreeStyleProject>> prop) throws Throwable {
         var p = r.createFreeStyleProject();
         p.addProperty(prop.object());
         var b = r.buildAndAssertSuccess(p);
         return XStreamSerializable.of(b.getAction(ParametersAction.class));
     }
 
+    @Ignore("inner class inside lambda breaks with an opaque NotSerializableException: RealJenkinsRuleTest; use TestBuilder.of instead")
+    @Test public void lambduh() throws Throwable {
+        rr.then(r -> {
+            r.createFreeStyleProject().getBuildersList().add(new TestBuilder() {
+                @Override public boolean perform(AbstractBuild<?, ?> build, Launcher launcher, BuildListener listener) throws InterruptedException, IOException {
+                    return true;
+                }
+            });
+        });
+    }
+
 }