import Foundationimport Testing@testable import CodexBarCore struct CostUsageJsonlScannerTests {    @Test    func `jsonl scanner handles lines across read chunks`() throws {        let root = try self.makeTemporaryRoot()        defer { try? FileManager.default.removeItem(at: root) }         let fileURL = root.appendingPathComponent("large-lines.jsonl", isDirectory: false)        let largeLine = String(repeating: "x", count: 300_000)        let contents = "\(largeLine)\nsmall\n"        try contents.write(to: fileURL, atomically: true, encoding: .utf8)         var scanned: [(count: Int, truncated: Bool)] = []        let endOffset = try CostUsageJsonl.scan(            fileURL: fileURL,            maxLineBytes: 400_000,            prefixBytes: 400_000)        { line in            scanned.append((line.bytes.count, line.wasTruncated))        }         #expect(endOffset == Int64(Data(contents.utf8).count))        #expect(scanned.count == 2)        #expect(scanned[0].count == 300_000)        #expect(scanned[0].truncated == false)        #expect(scanned[1].count == 5)        #expect(scanned[1].truncated == false)    }     @Test    func `jsonl scanner retains prefix for truncated lines`() throws {        let root = try self.makeTemporaryRoot()        defer { try? FileManager.default.removeItem(at: root) }         let fileURL = root.appendingPathComponent("truncated-lines.jsonl", isDirectory: false)        let shortLine = "ok"        let longLine = String(repeating: "a", count: 2000)        let contents = "\(shortLine)\n\(longLine)\n"        try contents.write(to: fileURL, atomically: true, encoding: .utf8)         var scanned: [CostUsageJsonl.Line] = []        _ = try CostUsageJsonl.scan(            fileURL: fileURL,            maxLineBytes: 10000,            prefixBytes: 64)        { line in            scanned.append(line)        }         #expect(scanned.count == 2)        #expect(String(data: scanned[0].bytes, encoding: .utf8) == "ok")        #expect(scanned[0].wasTruncated == false)        #expect(scanned[1].bytes.count == 64)        #expect(String(data: scanned[1].bytes, encoding: .utf8) == String(repeating: "a", count: 64))        #expect(scanned[1].wasTruncated == true)    }     private func makeTemporaryRoot() throws -> URL {        let root = FileManager.default.temporaryDirectory.appendingPathComponent(            "codexbar-cost-usage-jsonl-\(UUID().uuidString)",            isDirectory: true)        try FileManager.default.createDirectory(at: root, withIntermediateDirectories: true)        return root    }}