Phase 4 tests: DatabaseService migrations + ContextSelectionService DB paths

17 tests against throwaway in-memory DatabaseService instances: all
v1-v8 tables/columns exist post-migration, settings CRUD, conversation
save/load round-trip, instance isolation between separate in-memory
queues, and ContextSelectionService's DB-coupled paths (starring,
excluded-range summaries, smartSelection end to end) that were
previously untestable.

oAITests/ContextSelectionServiceDBTests.swift

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+//
+//  ContextSelectionServiceDBTests.swift
+//  oAITests
+//
+// SPDX-License-Identifier: PolyForm-Noncommercial-1.0.0
+// Copyright (C) 2026 Rune Olsen
+
+import Testing
+import Foundation
+@testable import oAI
+
+@Suite("ContextSelectionService DB-coupled paths, against a throwaway in-memory queue")
+struct ContextSelectionServiceDBTests {
+
+    /// Persists messages, then loads them back so their `id`s match the DB rows
+    /// (saveConversation assigns fresh row ids internally, distinct from the ids
+    /// on the Message values passed in).
+    private func persistedMessages(_ db: DatabaseService, _ messages: [Message]) throws -> (conversationId: UUID, messages: [Message]) {
+        let saved = try db.saveConversation(name: "Test", messages: messages)
+        let loaded = try db.loadConversation(id: saved.id)
+        return (saved.id, loaded?.1 ?? [])
+    }
+
+    // MARK: - isMessageStarred
+
+    @Test("A message with no metadata row is not starred")
+    func unstarredByDefault() throws {
+        let db = DatabaseService.makeInMemory()
+        let service = ContextSelectionService(db: db)
+        let (_, messages) = try persistedMessages(db, [Message(role: .user, content: "hi")])
+
+        #expect(service.isMessageStarred(messages[0]) == false)
+    }
+
+    @Test("A message starred via setMessageStarred reports starred")
+    func starredAfterSetting() throws {
+        let db = DatabaseService.makeInMemory()
+        let service = ContextSelectionService(db: db)
+        let (_, messages) = try persistedMessages(db, [Message(role: .user, content: "hi")])
+
+        try db.setMessageStarred(messageId: messages[0].id, starred: true)
+        #expect(service.isMessageStarred(messages[0]) == true)
+    }
+
+    // MARK: - getSummariesForExcludedRange
+
+    @Test("No summaries recorded returns an empty array")
+    func noSummariesReturnsEmpty() throws {
+        let db = DatabaseService.makeInMemory()
+        let service = ContextSelectionService(db: db)
+        let (conversationId, _) = try persistedMessages(db, [Message(role: .user, content: "hi")])
+
+        let summaries = service.getSummariesForExcludedRange(conversationId: conversationId, totalMessages: 30, selectedCount: 10)
+        #expect(summaries.isEmpty)
+    }
+
+    @Test("A summary covering only excluded messages is included")
+    func summaryForExcludedRangeIncluded() throws {
+        let db = DatabaseService.makeInMemory()
+        let service = ContextSelectionService(db: db)
+        let (conversationId, _) = try persistedMessages(db, [Message(role: .user, content: "hi")])
+
+        // 30 total, 10 selected -> messages 0..<20 are excluded
+        try db.saveConversationSummary(conversationId: conversationId, startIndex: 0, endIndex: 15, summary: "early stuff", model: nil, tokenCount: nil)
+
+        let summaries = service.getSummariesForExcludedRange(conversationId: conversationId, totalMessages: 30, selectedCount: 10)
+        #expect(summaries == ["early stuff"])
+    }
+
+    @Test("A summary covering messages that were kept is excluded")
+    func summaryForKeptRangeExcluded() throws {
+        let db = DatabaseService.makeInMemory()
+        let service = ContextSelectionService(db: db)
+        let (conversationId, _) = try persistedMessages(db, [Message(role: .user, content: "hi")])
+
+        // 30 total, 10 selected -> messages 0..<20 are excluded; this summary ends at 25, inside the kept range
+        try db.saveConversationSummary(conversationId: conversationId, startIndex: 15, endIndex: 25, summary: "later stuff", model: nil, tokenCount: nil)
+
+        let summaries = service.getSummariesForExcludedRange(conversationId: conversationId, totalMessages: 30, selectedCount: 10)
+        #expect(summaries.isEmpty)
+    }
+
+    // MARK: - smartSelection (end to end through the DB seam)
+
+    @Test("A starred older message is pulled in alongside the recent window")
+    func starredMessagePulledIntoSelection() throws {
+        let db = DatabaseService.makeInMemory()
+        let service = ContextSelectionService(db: db)
+
+        var all: [Message] = []
+        let base = Date()
+        for i in 0..<15 {
+            all.append(Message(role: i % 2 == 0 ? .user : .assistant, content: "msg \(i)", timestamp: base.addingTimeInterval(Double(i))))
+        }
+        let (_, persisted) = try persistedMessages(db, all)
+
+        // Star an old message that's outside the last-10 window (index 2)
+        try db.setMessageStarred(messageId: persisted[2].id, starred: true)
+
+        let window = service.smartSelection(allMessages: persisted, maxTokens: 100_000, conversationId: nil)
+        #expect(window.messages.contains { $0.id == persisted[2].id })
+    }
+
+    @Test("An unstarred, unimportant old message outside the recent window is excluded")
+    func unstarredOldMessageExcluded() throws {
+        let db = DatabaseService.makeInMemory()
+        let service = ContextSelectionService(db: db)
+
+        var all: [Message] = []
+        let base = Date()
+        for i in 0..<15 {
+            all.append(Message(role: i % 2 == 0 ? .user : .assistant, content: "msg \(i)", timestamp: base.addingTimeInterval(Double(i))))
+        }
+        let (_, persisted) = try persistedMessages(db, all)
+
+        let window = service.smartSelection(allMessages: persisted, maxTokens: 100_000, conversationId: nil)
+        #expect(window.messages.contains { $0.id == persisted[0].id } == false)
+        #expect(window.excludedCount == 5)
+    }
+}

oAITests/DatabaseServiceTests.swift

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+//
+//  DatabaseServiceTests.swift
+//  oAITests
+//
+// SPDX-License-Identifier: PolyForm-Noncommercial-1.0.0
+// Copyright (C) 2026 Rune Olsen
+
+import Testing
+import Foundation
+@testable import oAI
+
+@Suite("DatabaseService migrations, against a throwaway in-memory queue")
+struct DatabaseServiceMigrationTests {
+
+    @Test("All v1-v8 tables exist after migration")
+    func allTablesExist() {
+        let db = DatabaseService.makeInMemory()
+        let expectedTables = [
+            "conversations", "messages", "settings", "command_history",
+            "email_logs", "message_metadata", "message_embeddings",
+            "conversation_embeddings", "conversation_summaries",
+        ]
+        for table in expectedTables {
+            #expect(db.tableExists(table), "expected table \(table) to exist")
+        }
+    }
+
+    @Test("v4 adds modelId to messages and primaryModel to conversations")
+    func v4AddsModelColumns() {
+        let db = DatabaseService.makeInMemory()
+        #expect(db.columnNames(in: "messages").contains("modelId"))
+        #expect(db.columnNames(in: "conversations").contains("primaryModel"))
+    }
+
+    @Test("messages table has the expected v1 columns")
+    func messagesTableColumns() {
+        let db = DatabaseService.makeInMemory()
+        let columns = Set(db.columnNames(in: "messages"))
+        let expected: Set<String> = ["id", "conversationId", "role", "content", "tokens", "cost", "timestamp", "sortOrder"]
+        #expect(expected.isSubset(of: columns))
+    }
+
+    @Test("message_metadata table has the expected v6 columns")
+    func messageMetadataColumns() {
+        let db = DatabaseService.makeInMemory()
+        let columns = Set(db.columnNames(in: "message_metadata"))
+        #expect(columns == ["message_id", "importance_score", "user_starred", "summary", "chunk_index"])
+    }
+
+    @Test("conversation_summaries table has the expected v8 columns")
+    func conversationSummariesColumns() {
+        let db = DatabaseService.makeInMemory()
+        let columns = Set(db.columnNames(in: "conversation_summaries"))
+        #expect(columns == ["id", "conversation_id", "start_message_index", "end_message_index", "summary", "token_count", "created_at", "summary_model"])
+    }
+
+    @Test("A nonexistent table reports as absent, not a crash")
+    func nonexistentTableReportsAbsent() {
+        let db = DatabaseService.makeInMemory()
+        #expect(db.tableExists("not_a_real_table") == false)
+    }
+
+    @Test("Two in-memory instances are isolated from each other")
+    func instancesAreIsolated() throws {
+        let dbA = DatabaseService.makeInMemory()
+        let dbB = DatabaseService.makeInMemory()
+
+        _ = try dbA.saveConversation(name: "only in A", messages: [Message(role: .user, content: "hi")])
+
+        #expect(try dbA.listConversations().count == 1)
+        #expect(try dbB.listConversations().count == 0)
+    }
+}
+
+@Suite("DatabaseService settings CRUD, against a throwaway in-memory queue")
+struct DatabaseServiceSettingsTests {
+
+    @Test("Round-trips a plain setting")
+    func roundTripsSetting() {
+        let db = DatabaseService.makeInMemory()
+        db.setSetting(key: "theme", value: "dark")
+        #expect((try? db.loadAllSettings()["theme"]) == "dark")
+    }
+
+    @Test("Deletes a setting")
+    func deletesSetting() {
+        let db = DatabaseService.makeInMemory()
+        db.setSetting(key: "temp", value: "1")
+        db.deleteSetting(key: "temp")
+        #expect((try? db.loadAllSettings()["temp"]) == nil)
+    }
+}
+
+@Suite("DatabaseService conversation + message persistence, against a throwaway in-memory queue")
+struct DatabaseServiceConversationTests {
+
+    @Test("Saving a conversation round-trips its messages via loadConversation")
+    func savesAndLoadsConversation() throws {
+        let db = DatabaseService.makeInMemory()
+        let messages = [
+            Message(role: .user, content: "hello"),
+            Message(role: .assistant, content: "hi there"),
+        ]
+        let saved = try db.saveConversation(name: "Test Chat", messages: messages)
+
+        let loaded = try db.loadConversation(id: saved.id)
+        #expect(loaded?.0.name == "Test Chat")
+        #expect(loaded?.1.map(\.content) == ["hello", "hi there"])
+    }
+
+    @Test("System messages are excluded from persistence")
+    func systemMessagesExcluded() throws {
+        let db = DatabaseService.makeInMemory()
+        let messages = [
+            Message(role: .system, content: "tool call"),
+            Message(role: .user, content: "hello"),
+        ]
+        let saved = try db.saveConversation(name: "Test", messages: messages)
+        let loaded = try db.loadConversation(id: saved.id)
+        #expect(loaded?.1.count == 1)
+        #expect(loaded?.1.first?.content == "hello")
+    }
+}