Cucumber-style E2E scenarios covering consumer-shape and edge cases

affected-tests-gradle/build.gradle

@@ -47,12 +47,40 @@ configurations {
     functionalTestRuntimeOnly.extendsFrom testRuntimeOnly
 }
 
+dependencies {
+    // Cucumber-JVM + JUnit Platform Suite power the human-readable e2e
+    // scenario layer under src/functionalTest/resources/.../features.
+    // Every feature scenario spawns a real Gradle TestKit build so the
+    // assertions cover the exact plugin surface consumers like
+    // security-service see, not just the decision engine. See
+    // RunCucumberFunctionalTest for the JUnit Platform Suite entrypoint.
+    functionalTestImplementation 'io.cucumber:cucumber-java:7.25.0'
+    functionalTestImplementation 'io.cucumber:cucumber-junit-platform-engine:7.25.0'
+    // Required so Cucumber can constructor-inject the shared `World`
+    // into step-def classes; without a DI container, CucumberException
+    // "No suitable constructor" blows up at scenario discovery time.
+    functionalTestImplementation 'io.cucumber:cucumber-picocontainer:7.25.0'
+    functionalTestImplementation 'org.junit.platform:junit-platform-suite:1.14.3'
+    // JGit mirrors the way the core engine tests construct temp repos —
+    // reusing the same dependency means the feature-file scenarios build
+    // history with the exact semantics the engine will later parse.
+    functionalTestImplementation 'org.eclipse.jgit:org.eclipse.jgit:7.6.0.202603022253-r'
+}
+
 tasks.register('functionalTest', Test) {
-    description = 'Runs functional tests with Gradle TestKit.'
+    description = 'Runs functional tests with Gradle TestKit, including Cucumber e2e scenarios.'
     group = 'verification'
     testClassesDirs = sourceSets.functionalTest.output.classesDirs
     classpath = sourceSets.functionalTest.runtimeClasspath
     useJUnitPlatform()
+
+    // Cucumber-JVM's JUnit Platform engine scans the classpath resources of
+    // the running test JVM for .feature files. Without this, feature files
+    // placed under src/functionalTest/resources are packaged into the
+    // classpath but the engine still needs glue-code packages pointed at
+    // explicitly so step definitions get picked up deterministically.
+    systemProperty 'cucumber.glue', 'io.affectedtests.gradle.e2e.steps'
+    systemProperty 'cucumber.publish.quiet', 'true'
 }
 
 tasks.named('check') {

affected-tests-gradle/src/functionalTest/java/io/affectedtests/gradle/e2e/RunCucumberFunctionalTest.java

@@ -0,0 +1,37 @@
+package io.affectedtests.gradle.e2e;
+
+import org.junit.platform.suite.api.ConfigurationParameter;
+import org.junit.platform.suite.api.IncludeEngines;
+import org.junit.platform.suite.api.SelectClasspathResource;
+import org.junit.platform.suite.api.Suite;
+
+import static io.cucumber.junit.platform.engine.Constants.GLUE_PROPERTY_NAME;
+import static io.cucumber.junit.platform.engine.Constants.PLUGIN_PROPERTY_NAME;
+
+/**
+ * JUnit 5 Platform Suite entrypoint for the Cucumber e2e feature files.
+ *
+ * <p>Every feature file under {@code src/functionalTest/resources/io/affectedtests/gradle/e2e/features}
+ * is discovered by the Cucumber JUnit Platform engine at test time. Each
+ * scenario spawns a real Gradle TestKit build via {@link TestProject}, so
+ * the assertions cover the exact plugin surface that consumer builds like
+ * {@code security-service} see in production, not just the decision
+ * engine in isolation.
+ *
+ * <p>The suite is deliberately split across multiple {@code .feature}
+ * files (pilot scenarios, the Mode x Situation matrix, security-service
+ * consumer shape, DSL migration errors, edge cases). Splitting by theme
+ * keeps feature files self-contained — a reviewer landing in
+ * {@code 02-mode-situation-matrix.feature} sees every default action
+ * cell in one place without having to cross-reference other files.
+ *
+ * <p>Glue packages point at {@code steps/} so step definitions are
+ * discovered deterministically regardless of package scanning order.
+ */
+@Suite
+@IncludeEngines("cucumber")
+@SelectClasspathResource("io/affectedtests/gradle/e2e/features")
+@ConfigurationParameter(key = GLUE_PROPERTY_NAME, value = "io.affectedtests.gradle.e2e.steps")
+@ConfigurationParameter(key = PLUGIN_PROPERTY_NAME, value = "pretty,summary")
+public class RunCucumberFunctionalTest {
+}