add unhandled exception session test

features/unhandled_exception_session.feature

@@ -0,0 +1,14 @@
+Feature: Android support
+
+Scenario: Test handled Android Exception
+    When I run "UnhandledExceptionSessionScenario" with the defaults
+    Then I should receive a request
+    And the request is a valid for the error reporting API
+    And the exception "errorClass" equals "java.lang.RuntimeException"
+    And the exception "message" equals "UnhandledExceptionSessionScenario"
+    And the event "session" is not null
+    And the event "session.id" is not null
+    And the event "session.startedAt" is not null
+    And the event "session.events" is not null
+    And the payload field "events.0.session.events.handled" equals 0
+    And the payload field "events.0.session.events.unhandled" equals 1

mazerunner/src/main/java/com/bugsnag/android/mazerunner/scenarios/UnhandledExceptionSessionScenario.kt

@@ -0,0 +1,20 @@
+package com.bugsnag.android.mazerunner.scenarios
+
+import android.content.Context
+import com.bugsnag.android.Bugsnag
+import com.bugsnag.android.Configuration
+
+/**
+ * Sends an unhandled exception to Bugsnag, which includes session data.
+ */
+internal class UnhandledExceptionSessionScenario(config: Configuration,
+                                                 context: Context) : Scenario(config, context) {
+
+    override fun run() {
+        super.run()
+        disableSessionDelivery()
+        Bugsnag.startSession()
+        throw generateException()
+    }
+
+}