test: Add basic snapshot test coverage for EventView

This commit adds a basic snapshot test for EventView, and also adds some testing infrastructure to help with mocking NostrDB behavior.

Test
----

PASS

Device: iOS 17.0 Simulator
iOS: 17.0
Damus: This commit
Steps: Run `EventViewTests`
Results: Snapshot matches baseline reference added

damusTests/Mocking/MockDamusState.swift

@@ -0,0 +1,66 @@
+//
+//  MockDamusState.swift
+//  damusTests
+//
+//  Created by Daniel D’Aquino on 2023-10-13.
+//
+
+import Foundation
+@testable import damus
+
+// Generates a test damus state with configurable mock parameters
+func generate_test_damus_state(
+    mock_profile_info: [Pubkey: Profile]?
+) -> DamusState {
+    // Create a unique temporary directory
+    var tempDir: String!
+    do {
+        let fileManager = FileManager.default
+        let temp = fileManager.temporaryDirectory.appendingPathComponent(UUID().uuidString)
+        try fileManager.createDirectory(at: temp, withIntermediateDirectories: true, attributes: nil)
+        tempDir = temp.absoluteString
+    } catch {
+        tempDir = "."
+    }
+
+    print("opening \(tempDir!)")
+    let ndb = Ndb(path: tempDir)!
+    let our_pubkey = test_pubkey
+    let pool = RelayPool(ndb: ndb)
+    let settings = UserSettingsStore()
+    
+    let profiles: Profiles = {
+        guard let mock_profile_info, let profiles: Profiles = MockProfiles(mocked_profiles: mock_profile_info, ndb: ndb) else {
+            return Profiles.init(ndb: ndb)
+        }
+        return profiles
+    }()
+    
+    let damus = DamusState(pool: pool,
+                           keypair: test_keypair,
+                           likes: .init(our_pubkey: our_pubkey),
+                           boosts: .init(our_pubkey: our_pubkey),
+                           contacts: .init(our_pubkey: our_pubkey),
+                           profiles: profiles,
+                           dms: .init(our_pubkey: our_pubkey),
+                           previews: .init(),
+                           zaps: .init(our_pubkey: our_pubkey),
+                           lnurls: .init(),
+                           settings: settings,
+                           relay_filters: .init(our_pubkey: our_pubkey),
+                           relay_model_cache: .init(),
+                           drafts: .init(),
+                           events: .init(ndb: ndb),
+                           bookmarks: .init(pubkey: our_pubkey),
+                           postbox: .init(pool: pool),
+                           bootstrap_relays: .init(),
+                           replies: .init(our_pubkey: our_pubkey),
+                           muted_threads: .init(keypair: test_keypair),
+                           wallet: .init(settings: settings),
+                           nav: .init(),
+                           music: .init(onChange: {_ in }),
+                           video: .init(),
+                           ndb: ndb)
+
+    return damus
+}