JUnit5: first, experimental support for dynamic tests

build.gradle

@@ -125,6 +125,8 @@ configure(subprojects.findAll {!it.name.contains("android")}) {
         }
         testLogging {
             showStandardStreams = true
+            events "failed"
+            exceptionFormat "full"
         }
     }
 

docs/junit5.adoc

@@ -81,6 +81,43 @@ public class JGiven5ScenarioTest
 }
 ----
 
+=== Dynamic Tests
+JUnit 5 introduces so-called _dynamic tests_.
+Dynamic tests are created completely differently than normal JUnit 5 tests, by using _factory methods_.
+A factory method is a method annotated with `@TestFactory` returning a sequence of `DynamicTest` instances.
+Normally you create instances of `DynamicTest` by using the `DynamicTest.dynamicTest` method.
+This method takes two parameters: a display name in form of a String and a lambda expression that contains
+the actual test implementation.
+
+==== Dynamic JGiven Tests
+To write dynamic JGiven tests, all you have to do is to use the method `DynamicJGivenTest.dynamicJGivenTest`
+to create instances of `DynamicTest`.
+The difference to the JUnit 5 method is that the lambda expression of the JGiven method takes a `ScenarioBase` parameter.
+You use this parameter to add stages to the scenario.
+
+[source,java]
+----
+@ExtendWith(JGivenExtension.class)
+public class DynamicTestTest {
+
+    @TestFactory
+    Collection<DynamicTest> dynamicTests() {
+        return Arrays.asList(
+            dynamicJGivenTest("1st dynamic test", (scenario) -> {
+                scenario.given(GivenStage.class)
+                        .some_state();
+                scenario.when(WhenStage.class)
+                        .some_action();
+            })
+        );
+    }
+}
+----
+
+CAUTION: Dynamic JGiven Tests is currently a highly experimental feature and will most likely
+be changed in backwards-incompatible ways in future versions of JGiven. Use with caution.
+Feedback is welcome!
+
 === Example Project
 
 You find a complete example project on GitHub: https://github.com/TNG/JGiven/tree/master/example-projects/junit5

jgiven-core/src/main/java/com/tngtech/jgiven/impl/ReportModelHolder.java

@@ -0,0 +1,26 @@
+package com.tngtech.jgiven.impl;
+
+import com.tngtech.jgiven.report.model.ReportModel;
+
+public class ReportModelHolder {
+    private final ThreadLocal<ReportModel> reportModel = new ThreadLocal<ReportModel>();
+
+    private static final ReportModelHolder INSTANCE = new ReportModelHolder();
+
+    public static ReportModelHolder get() {
+        return INSTANCE;
+    }
+
+    public ReportModel getReportModelOfCurrentThread() {
+        return reportModel.get();
+    }
+
+    public void setReportModelOfCurrentThread(ReportModel reportModel) {
+        this.reportModel.set(reportModel);
+    }
+
+    public void removeReportModelOfCurrentThread() {
+        reportModel.remove();
+    }
+
+}

jgiven-core/src/main/java/com/tngtech/jgiven/impl/Scenario.java

@@ -41,10 +41,6 @@ public THEN getThenStage() {
         return thenStage;
     }
 
-    public void addIntroWord( String word ) {
-        executor.addIntroWord( word );
-    }
-
     /**
      * Creates a scenario with 3 different steps classes.
      *

jgiven-core/src/main/java/com/tngtech/jgiven/impl/ScenarioBase.java

@@ -117,4 +117,76 @@ public void section( String sectionTitle ) {
     public void setStageCreator(StageCreator stageCreator) {
         this.executor.setStageCreator(stageCreator);
     }
+
+    public void addIntroWord( String word ) {
+        executor.addIntroWord( word );
+    }
+
+    /**
+     * Alias for {@link #addStage}
+     */
+    public <T> T stage(Class<T> stageClass) {
+        return addStage(stageClass);
+    }
+
+    /**
+     * Alias for {@link #addIntroWord(String)}
+     * @see #addIntroWord(String)
+     */
+    public ScenarioBase intro(String introWord) {
+        addIntroWord(introWord);
+        return this;
+    }
+
+    /**
+     * Convenience method for adding the 'given' intro word
+     * and adding a stage class. Equivalent to
+     *
+     * <pre>
+     *     addIntroWord("given");
+     *     return addStage(stageClass);
+     * </pre>
+     *
+     * @see #addIntroWord(String)
+     * @see #addStage(Class)
+     */
+    public <T> T given(Class<T> stageClass) {
+        addIntroWord("given");
+        return addStage(stageClass);
+    }
+
+    /**
+     * Convenience method for adding the 'when' intro word
+     * and adding a stage class. Equivalent to
+     *
+     * <pre>
+     *     addIntroWord("when");
+     *     return addStage(stageClass);
+     * </pre>
+     *
+     * @see #addIntroWord(String)
+     * @see #addStage(Class)
+     */
+    public <T> T when(Class<T> stageClass) {
+        addIntroWord("when");
+        return addStage(stageClass);
+    }
+
+    /**
+     * Convenience method for adding the 'then' intro word
+     * and adding a stage class. Equivalent to
+     *
+     * <pre>
+     *     addIntroWord("then");
+     *     return addStage(stageClass);
+     * </pre>
+     *
+     * @see #addIntroWord(String)
+     * @see #addStage(Class)
+     */
+    public <T> T then(Class<T> stageClass) {
+        addIntroWord("then");
+        return addStage(stageClass);
+    }
+
 }

jgiven-junit5/src/main/java/com/tngtech/jgiven/junit5/DynamicJGivenTest.java

@@ -0,0 +1,61 @@
+package com.tngtech.jgiven.junit5;
+
+import com.tngtech.jgiven.impl.ReportModelHolder;
+import com.tngtech.jgiven.impl.ScenarioBase;
+import com.tngtech.jgiven.report.model.ReportModel;
+import org.junit.jupiter.api.Assumptions;
+import org.junit.jupiter.api.DynamicTest;
+import org.junit.jupiter.api.function.Executable;
+
+import java.util.EnumSet;
+
+import static com.tngtech.jgiven.report.model.ExecutionStatus.FAILED;
+import static com.tngtech.jgiven.report.model.ExecutionStatus.SUCCESS;
+
+/**
+ * @since 0.15.0
+ */
+public class DynamicJGivenTest {
+
+    /**
+     * JGiven-specific factory method for creating dynamic JUnit 5 tests
+     *
+     * <h1>HIGHLY EXPERIMENTAL</h1>
+     *
+     * Most likely this method will change in future versions of JGiven, please don't
+     * use this method for any serious projects, yet.
+     *
+     * @see DynamicTest#dynamicTest(String, Executable)
+     * @param displayName the display name for the dynamic test; never
+     *                    {@code null} or blank
+     * @param executable the executable code block for the dynamic test;
+     *                    never {@code null}
+     */
+    public static DynamicTest dynamicJGivenTest(String displayName, JGivenExecutable executable) {
+        return DynamicTest.dynamicTest(displayName, executableWrapper(displayName, executable));
+    }
+
+    private static Executable executableWrapper(final String displayName, final JGivenExecutable executable) {
+        return new Executable() {
+            @Override
+            public void execute() throws Throwable {
+                ScenarioBase scenario = new ScenarioBase();
+                ReportModel reportModel = ReportModelHolder.get().getReportModelOfCurrentThread();
+                scenario.setModel(reportModel);
+                scenario.startScenario(displayName);
+                try {
+                    executable.execute(scenario);
+
+                    scenario.finished();
+                    // ignore test when scenario is not implemented
+                    Assumptions.assumeTrue( EnumSet.of( SUCCESS, FAILED ).contains( scenario.getScenarioModel().getExecutionStatus() ) );
+                } catch( Exception e ) {
+                    scenario.finished();
+                    scenario.getExecutor().failed( e );
+                    throw e;
+                }
+            }
+        };
+    }
+
+}

jgiven-junit5/src/main/java/com/tngtech/jgiven/junit5/JGivenExecutable.java

@@ -0,0 +1,20 @@
+package com.tngtech.jgiven.junit5;
+
+import com.tngtech.jgiven.impl.ScenarioBase;
+
+/**
+ * JGiven-specific variant of the {@link org.junit.jupiter.api.function.Executable} interface
+ * of JUnit 5 for writing dynamic tests.
+ *
+ * <h1>HIGHLY EXPERIMENTAL</h1>
+ *
+ * Most likely this interface will change in future versions of JGiven without prior-notice,
+ * please don't use this for any serious projects, yet.
+ *
+ * @see org.junit.jupiter.api.function.Executable
+ * @since 0.15.0
+ */
+@FunctionalInterface
+public interface JGivenExecutable {
+    void execute(ScenarioBase scenario) throws Throwable;
+}

jgiven-junit5/src/main/java/com/tngtech/jgiven/junit5/JGivenExtension.java

@@ -7,10 +7,9 @@
 import java.util.EnumSet;
 import java.util.List;
 
-import com.tngtech.jgiven.config.ConfigurationUtil;
-import com.tngtech.jgiven.impl.Config;
 import org.junit.jupiter.api.Assumptions;
 import org.junit.jupiter.api.Tag;
+import org.junit.jupiter.api.TestFactory;
 import org.junit.jupiter.api.extension.AfterAllCallback;
 import org.junit.jupiter.api.extension.AfterEachCallback;
 import org.junit.jupiter.api.extension.BeforeAllCallback;
@@ -22,6 +21,8 @@
 import org.junit.jupiter.api.extension.ExtensionContext.Namespace;
 
 import com.tngtech.jgiven.base.ScenarioTestBase;
+import com.tngtech.jgiven.config.ConfigurationUtil;
+import com.tngtech.jgiven.impl.ReportModelHolder;
 import com.tngtech.jgiven.impl.ScenarioBase;
 import com.tngtech.jgiven.impl.ScenarioHolder;
 import com.tngtech.jgiven.report.impl.CommonReportHelper;
@@ -43,6 +44,7 @@
  *
  * @see ScenarioTest
  * @see SimpleScenarioTest
+ * @since 0.14.0
  */
 public class JGivenExtension implements
         TestInstancePostProcessor,
@@ -64,26 +66,42 @@ public void beforeAll( ContainerExtensionContext context ) throws Exception {
         }
         context.getStore( NAMESPACE ).put( REPORT_MODEL, reportModel );
 
-        ConfigurationUtil.getConfiguration(context.getTestClass().get())
-                .configureTag(Tag.class)
-                .description("JUnit 5 Tag")
-                .color("orange");
+        ConfigurationUtil.getConfiguration( context.getTestClass().get() )
+            .configureTag( Tag.class )
+            .description( "JUnit 5 Tag" )
+            .color( "orange" );
     }
 
     @Override
     public void afterAll( ContainerExtensionContext context ) throws Exception {
+        ReportModelHolder.get().removeReportModelOfCurrentThread();
         new CommonReportHelper().finishReport( (ReportModel) context.getStore( NAMESPACE ).get( REPORT_MODEL ) );
     }
 
     @Override
     public void beforeEach( TestExtensionContext context ) throws Exception {
+        ReportModel reportModel = (ReportModel) context.getStore( NAMESPACE ).get( REPORT_MODEL );
+        ReportModelHolder.get().setReportModelOfCurrentThread( reportModel );
+
+        if( isTestFactory( context ) ) {
+            return;
+        }
+
         List<NamedArgument> args = new ArrayList<NamedArgument>();
         getScenario().startScenario( context.getTestClass().get(), context.getTestMethod().get(), args );
+    }
 
+    private boolean isTestFactory( TestExtensionContext context ) {
+        return context.getTestMethod().get().getAnnotation( TestFactory.class ) != null;
     }
 
     @Override
     public void afterEach( TestExtensionContext context ) throws Exception {
+        ReportModelHolder.get().removeReportModelOfCurrentThread();
+
+        if( isTestFactory( context ) ) {
+            return;
+        }
 
         ScenarioBase scenario = getScenario();
         try {

jgiven-junit5/src/main/java/com/tngtech/jgiven/junit5/ScenarioTest.java

@@ -17,6 +17,8 @@
  *
  * @see JGivenExtension
  * @see SimpleScenarioTest
+ * @since 0.14.0
+ *
  */
 @ExtendWith( JGivenExtension.class )
 public class ScenarioTest<GIVEN, WHEN, THEN> extends ScenarioTestBase<GIVEN, WHEN, THEN> {

jgiven-junit5/src/main/java/com/tngtech/jgiven/junit5/SimpleScenarioTest.java

@@ -1,12 +1,15 @@
 package com.tngtech.jgiven.junit5;
 
-import com.tngtech.jgiven.base.SimpleScenarioTestBase;
 import org.junit.jupiter.api.extension.ExtendWith;
 
-import com.tngtech.jgiven.base.ScenarioTestBase;
+import com.tngtech.jgiven.base.SimpleScenarioTestBase;
 import com.tngtech.jgiven.impl.Scenario;
 
-
+/**
+ * JUnit 5
+ *
+ * @since 0.14.0
+*/
 @ExtendWith( JGivenExtension.class )
 public class SimpleScenarioTest<STAGE> extends SimpleScenarioTestBase<STAGE> {
 

jgiven-junit5/src/test/java/com/tngtech/jgiven/junit5/test/DynamicTestTest.java

@@ -11,6 +11,7 @@
 import java.util.Arrays;
 import java.util.Collection;
 
+import static com.tngtech.jgiven.junit5.DynamicJGivenTest.dynamicJGivenTest;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 import static org.junit.jupiter.api.DynamicTest.dynamicTest;
@@ -23,8 +24,19 @@ public class DynamicTestTest {
     @TestFactory
     Collection<org.junit.jupiter.api.DynamicTest> dynamicTestsFromCollection() {
         return Arrays.asList(
-                dynamicTest("1st dynamic test", () -> assertTrue(true)),
-                dynamicTest("2nd dynamic test", () -> assertEquals(4, 2 * 2))
+                dynamicJGivenTest("1st dynamic test", (s) -> {
+                    s.given(GivenStage.class)
+                            .some_state();
+                    s.when(WhenStage.class)
+                            .some_action();
+
+                }),
+                dynamicJGivenTest("2nd dynamic test", (scenario) -> {
+                    scenario.given(GivenStage.class)
+                            .some_state()
+                            .when().some_action()
+                            .then().some_outcome();
+                })
         );
     }