Adding new protocol method implementation.

Sources/Persister/MemoryCache.swift

@@ -38,6 +38,10 @@ extension MemoryCache: Cache {
     }
 
     public func write<Item: Codable>(item: Item, forKey key: String) throws {
+        try write(item: item, forKey: key, expirationPolicy: expirationPolicy)
+    }
+
+    public func write<Item>(item: Item, forKey key: String, expirationPolicy: CacheExpirationPolicy) throws where Item : Decodable, Item : Encodable {
         let expirationDate = expirationPolicy.expirationDate(from: Date())
         let container = ItemContainer(item: item, expirationDate: expirationDate)
 

Sources/Persister/Persister.swift

@@ -48,6 +48,11 @@ extension Persister: Cache {
         try diskCache.write(item: item, forKey: key)
     }
 
+    public func write<Item: Codable>(item: Item, forKey key: String, expirationPolicy: CacheExpirationPolicy) throws {
+        try memoryCache.write(item: item, forKey: key, expirationPolicy: expirationPolicy)
+        try diskCache.write(item: item, forKey: key, expirationPolicy: expirationPolicy)
+    }
+
     public func remove(forKey key: String) throws {
         try memoryCache.remove(forKey: key)
         try diskCache.remove(forKey: key)

Tests/DiskCacheTests.swift

@@ -91,4 +91,23 @@ final class DiskCacheTests: XCTestCase {
             }
         }
     }
+
+    func testUsesCorrectExpirationPolicy() throws {
+        let expectation = XCTestExpectation(description: "Only one item should have been removed.")
+
+        let cache = DiskCache(rootDirectoryURL: diskURL, expirationPolicy: .afterInterval(1))
+        try cache.write(item: TestCodable(), forKey: itemKey, expirationPolicy: .afterInterval(500))
+
+        DispatchQueue.main.asyncAfter(deadline: .now() + 2) {
+
+            try? cache.removeExpired()
+
+            let item1: ItemContainer<TestCodable>? = try? cache.read(forKey: self.itemKey)
+
+            XCTAssertNotNil(item1)
+
+            expectation.fulfill()
+        }
+        wait(for: [expectation], timeout: 5)
+    }
 }