Fix Java8StepDefinition.isDefinedAt

Closes #1254

Author: mpkorstanje

java8/src/main/java/cucumber/runtime/java8/Java8StepDefinition.java

@@ -38,7 +38,7 @@ public <T extends StepdefBody> Java8StepDefinition(String pattern, long timeoutM
         this.body = body;
 
         this.argumentMatcher = new JdkPatternArgumentMatcher(this.pattern);
-        this.location = new Exception().getStackTrace()[3];
+        this.location = new Exception().getStackTrace()[2];
         this.method = getAcceptMethod(body.getClass());
         try {
             Class<?>[] arguments = resolveRawArguments(bodyClass, body.getClass());

java8/src/test/java/cucumber/runtime/java8/Java8LambdaStepDefinitionMarksCorrectStackElementTest.java

@@ -0,0 +1,64 @@
+package cucumber.runtime.java8;
+
+import cucumber.runtime.HookDefinition;
+import cucumber.runtime.StepDefinition;
+import cucumber.runtime.java.LambdaGlueRegistry;
+import org.hamcrest.CustomTypeSafeMatcher;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.ExpectedException;
+
+public class Java8LambdaStepDefinitionMarksCorrectStackElementTest {
+
+    @Rule
+    public ExpectedException expectedException = ExpectedException.none();
+
+    private final MyLambdaGlueRegistry myLambdaGlueRegistry = new MyLambdaGlueRegistry();
+
+    @Test
+    public void exception_from_step_should_be_defined_at_step_definition_class() throws Throwable {
+        LambdaGlueRegistry.INSTANCE.set(myLambdaGlueRegistry);
+        new SomeLambdaStepDefs();
+        final StepDefinition stepDefinition = myLambdaGlueRegistry.getStepDefinition();
+
+        expectedException.expect(new CustomTypeSafeMatcher<Throwable>("exception with matching stack trace") {
+            @Override
+            protected boolean matchesSafely(Throwable item) {
+                for (StackTraceElement stackTraceElement : item.getStackTrace()) {
+                    if(stepDefinition.isDefinedAt(stackTraceElement)){
+                        return SomeLambdaStepDefs.class.getName().equals(stackTraceElement.getClassName());
+                    }
+
+                }
+                return false;
+            }
+        });
+
+        stepDefinition.execute("en", new Object[0]);
+    }
+
+
+    private class MyLambdaGlueRegistry implements LambdaGlueRegistry {
+
+        private StepDefinition stepDefinition;
+
+        @Override
+        public void addStepDefinition(StepDefinition stepDefinition) {
+            this.stepDefinition = stepDefinition;
+        }
+
+        @Override
+        public void addBeforeHookDefinition(HookDefinition beforeHook) {
+
+        }
+
+        @Override
+        public void addAfterHookDefinition(HookDefinition afterHook) {
+
+        }
+
+        public StepDefinition getStepDefinition() {
+            return stepDefinition;
+        }
+    }
+}

java8/src/test/java/cucumber/runtime/java8/SomeLambdaStepDefs.java

@@ -0,0 +1,13 @@
+package cucumber.runtime.java8;
+
+import cucumber.api.java8.En;
+
+final class SomeLambdaStepDefs implements En {
+
+    SomeLambdaStepDefs() {
+        Given("I have a some step definition", () -> {
+            throw new Exception();
+        });
+    }
+
+}