Add test case for empty fields, and rename startSession

Author: mrober

firebase-sessions/src/main/kotlin/com/google/firebase/sessions/FirebaseSessions.kt

@@ -40,8 +40,8 @@ class FirebaseSessions internal constructor(firebaseApp: FirebaseApp) {
   fun greeting(): String = "Matt says hi!"
 
   private fun initiateSessionStart() {
-    val sessionState = sessionGenerator.generateNewSession()
-    val sessionEvent = SessionEvents.sessionStart(sessionState)
+    val sessionDetails = sessionGenerator.generateNewSession()
+    val sessionEvent = SessionEvents.startSession(sessionDetails)
 
     Log.i(TAG, "Initiate session start: $sessionEvent")
   }

firebase-sessions/src/main/kotlin/com/google/firebase/sessions/SessionEvents.kt

@@ -54,7 +54,7 @@ internal object SessionEvents {
       .build()
 
   /** Construct a Session Start event */
-  fun sessionStart(sessionDetails: SessionDetails) =
+  fun startSession(sessionDetails: SessionDetails) =
     SessionEvent(
       eventType = EventType.SESSION_START,
       sessionData =

firebase-sessions/src/test/kotlin/com/google/firebase/sessions/SessionEventEncoderTest.kt

@@ -56,6 +56,38 @@ class SessionEventEncoderTest {
       )
   }
 
+  @Test
+  fun sessionEvent_emptyValues_encodesToJson() {
+    val sessionEvent =
+      SessionEvent(
+        eventType = EventType.EVENT_TYPE_UNKNOWN,
+        sessionData =
+          SessionInfo(
+            sessionId = "",
+            firstSessionId = "",
+            sessionIndex = 0,
+          ),
+      )
+
+    val json = SESSION_EVENT_ENCODER.encode(sessionEvent)
+
+    assertThat(json)
+      .isEqualTo(
+        """
+        {
+          "event_type":0,
+          "session_data":{
+            "session_id":"",
+            "first_session_id":"",
+            "session_index":0
+          }
+        }
+        """
+          .lines()
+          .joinToString("") { it.trim() }
+      )
+  }
+
   @Test
   fun eventType_numberedEnum_encodesToJson() {
     val json =

firebase-sessions/src/test/kotlin/com/google/firebase/sessions/SessionEventTest.kt

@@ -30,7 +30,7 @@ class SessionEventTest {
         sessionIndex = 3,
       )
 
-    val sessionEvent = SessionEvents.sessionStart(sessionDetails)
+    val sessionEvent = SessionEvents.startSession(sessionDetails)
 
     assertThat(sessionEvent)
       .isEqualTo(