Add support for IterationSelector to run individual iterations (#1379)

Co-authored-by: Leonard Brünings <leonard.bruenings@gradle.com>

Author: marcphilipp

spock-core/src/main/java/org/spockframework/runtime/MethodSelectorResolver.java

@@ -20,8 +20,7 @@ public Resolution resolve(MethodSelector selector, Context context) {
 
     String methodName = selector.getMethodName();
     Predicate<FeatureInfo> filter = feature ->
-      feature.getFeatureMethod().getReflection().getName().equals(methodName)
-        || methodName.equals(feature.getName());
+      reflectionNameOrMethodNameEquals(methodName, feature);
 
     DiscoverySelector parentSelector = selectClass(selector.getJavaClass());
     return resolveAllowingAllIndexes(context, parentSelector, filter);
@@ -53,6 +52,21 @@ public Resolution resolve(UniqueIdSelector selector, Context context) {
     return Resolution.unresolved();
   }
 
+  @Override
+  public Resolution resolve(IterationSelector selector, Context context) {
+    if (selector.getParentSelector() instanceof MethodSelector) {
+      MethodSelector methodSelector = (MethodSelector) selector.getParentSelector();
+
+      return resolveWithIterationFilter(
+        context,
+        selectClass(methodSelector.getJavaClass()),
+        feature -> reflectionNameOrMethodNameEquals(methodSelector.getMethodName(), feature),
+        iterationFilter -> selector.getIterationIndices().forEach(iterationFilter::allow)
+      );
+    }
+    return SelectorResolver.super.resolve(selector, context);
+  }
+
   private Resolution resolveAllowingAllIndexes(Context context, DiscoverySelector parentSelector, Predicate<FeatureInfo> featureFilter) {
     return resolveWithIterationFilter(context, parentSelector, featureFilter, IterationFilter::allowAll);
   }
@@ -90,4 +104,9 @@ private TestDescriptor handle(TestDescriptor testDescriptor, Predicate<FeatureIn
     }
     return null;
   }
+
+  private static boolean reflectionNameOrMethodNameEquals(String methodName, FeatureInfo feature) {
+    return feature.getFeatureMethod().getReflection().getName().equals(methodName)
+      || methodName.equals(feature.getName());
+  }
 }

spock-testkit/src/test/groovy/spock/platform/SpockHelloWorldTest.java

@@ -1,5 +1,6 @@
 package spock.platform;
 
+import org.junit.platform.engine.discovery.MethodSelector;
 import org.junit.platform.launcher.Launcher;
 import org.junit.platform.launcher.TestPlan;
 import org.junit.platform.launcher.core.LauncherConfig;
@@ -71,7 +72,7 @@ void packageSelectorsAreResolved() {
   }
 
   @Test
-  void iterationsAreResolved() {
+  void iterationsAreResolvedViaUniqueIdSelector() {
     UniqueId featureMethodUniqueId = UniqueId.forEngine("spock")
       .append("spec", UnrollTestCase.class.getName())
       .append("feature", "$spock_feature_0_0");
@@ -96,6 +97,37 @@ void iterationsAreResolved() {
     );
   }
 
+  @Test
+  void iterationsAreResolvedViaIterationSelector() {
+    UniqueId featureMethodUniqueId = UniqueId.forEngine("spock")
+      .append("spec", UnrollTestCase.class.getName())
+      .append("feature", "$spock_feature_0_0");
+    MethodSelector methodSelector = selectMethod(UnrollTestCase.class, "unrollMe");
+
+    execute(
+      selectIteration(methodSelector, 1),
+      stats -> stats.started(2).succeeded(1).failed(1)
+    );
+    execute(
+      selectIteration(methodSelector, 0, 2),
+      stats -> stats.started(3).succeeded(3)
+    );
+    execute(
+      asList(
+        selectIteration(methodSelector, 1),
+        selectUniqueId(featureMethodUniqueId)
+      ),
+      stats -> stats.started(4).succeeded(3).failed(1)
+    );
+    execute(
+      asList(
+        selectIteration(methodSelector, 0),
+        selectUniqueId(featureMethodUniqueId.append("iteration", "2"))
+      ),
+      stats -> stats.started(3).succeeded(3)
+    );
+  }
+
   @Test
   void verifyUnrollExample() {
     execute(selectClass(UnrollTestCase.class), stats -> stats.started(13).succeeded(12).failed(1));