[JUnit, TestNg] Use switch statement consistently

 The AndroidInstrumentationReporter, JUnitReporter and TestNgReporter have
  some subtle style difference between. This made the code base a bit harder to
  understand.

  Using a switch-case-default-throws pattern makes it consistent and will make
  errors explicit when more states are added.

Author: mpkorstanje

junit/src/main/java/cucumber/runtime/junit/JUnitReporter.java

@@ -132,6 +132,8 @@ void handleStepResult(TestStep testStep, Result result) {
             stepErrors.add(error);
             stepNotifier.addFailure(error);
             break;
+        default:
+            throw new IllegalStateException("Unexpected result status: " + result.getStatus());
         }
         stepNotifier.fireTestFinished();
     }

testng/src/main/java/cucumber/api/testng/TestNgReporter.java

@@ -3,14 +3,14 @@
 import static org.testng.Reporter.getCurrentTestResult;
 import static org.testng.Reporter.log;
 
-import cucumber.runtime.Utils;
 import cucumber.api.Result;
 import cucumber.api.event.EventHandler;
 import cucumber.api.event.EventPublisher;
 import cucumber.api.event.TestRunFinished;
 import cucumber.api.event.TestStepFinished;
 import cucumber.api.formatter.Formatter;
 import cucumber.api.formatter.NiceAppendable;
+import cucumber.runtime.Utils;
 import org.testng.ITestResult;
 
 class TestNgReporter implements Formatter {
@@ -50,19 +50,27 @@ void uri(String uri) {
 
     private void result(String stepText, Result result) {
         logResult(stepText, result);
-
-        if (result.is(Result.Type.FAILED) || result.is(Result.Type.AMBIGUOUS)) {
-            ITestResult tr = getCurrentTestResult();
-            tr.setThrowable(result.getError());
-            tr.setStatus(ITestResult.FAILURE);
-        } else if (result.is(Result.Type.SKIPPED)) {
-            ITestResult tr = getCurrentTestResult();
-            tr.setThrowable(result.getError());
-            tr.setStatus(ITestResult.SKIP);
-        } else if (result.is(Result.Type.UNDEFINED) || result.is(Result.Type.PENDING)) {
-            ITestResult tr = getCurrentTestResult();
-            tr.setThrowable(result.getError());
-            tr.setStatus(ITestResult.FAILURE);
+        ITestResult tr = getCurrentTestResult();
+
+        switch (result.getStatus()) {
+            case PASSED:
+                // do nothing
+                break;
+            case FAILED:
+            case AMBIGUOUS:
+                tr.setThrowable(result.getError());
+                tr.setStatus(ITestResult.FAILURE);
+                break;
+            case SKIPPED:
+                tr.setThrowable(result.getError());
+                tr.setStatus(ITestResult.SKIP);
+            case UNDEFINED:
+            case PENDING:
+                tr.setThrowable(result.getError());
+                tr.setStatus(ITestResult.FAILURE);
+                break;
+            default:
+                throw new IllegalStateException("Unexpected result status: " + result.getStatus());
         }
     }