Add tests for loading Classic accounts.

Tidy up warnings and fix a few bugs that were revealed.

UnitTests/SupportingFiles/target.yml

@@ -49,7 +49,9 @@ targets:
     sources:
     - path: ../Sources
     - path: ../SupportingFiles
-    - path: ../../DevelopmentAssets
+    - path: ../../DevelopmentAssets/Media
+    - path: ../../DevelopmentAssets/ClassicAppFixtures
+      buildPhase: resources # Necessary to add binary files to the target.
     - path: ../../ElementX/Sources/Other/Extensions/Publisher.swift
     - path: ../../ElementX/Sources/Other/Extensions/XCTestCase.swift
     - path: ../../ElementX/Sources/Other/InfoPlistReader.swift