diff --git a/Package.swift b/Package.swift
index a7e634a..60e5267 100644
--- a/Package.swift
+++ b/Package.swift
@@ -27,6 +27,11 @@ let package = Package(
       dependencies: ["MaxMindDecoder"],
       path: "Sources/Index"
     ),
+    .target(
+      name: "Metadata",
+      dependencies: ["MaxMindDecoder"],
+      path: "Sources/Metadata"
+    ),
 
     .target(
       name: "MaxMindDBReader",
@@ -54,6 +59,11 @@ let package = Package(
       dependencies: ["Index"]
     ),
 
+    .testTarget(
+      name: "MetadataTests",
+      dependencies: ["Metadata"]
+    ),
+
     .testTarget(
       name: "MaxMindDecoderTests",
       dependencies: ["MaxMindDecoder"]
diff --git a/Sources/MaxMindDBReader/InMemoryReader.swift b/Sources/MaxMindDBReader/InMemoryReader.swift
index bbcbc17..79c8f72 100644
--- a/Sources/MaxMindDBReader/InMemoryReader.swift
+++ b/Sources/MaxMindDBReader/InMemoryReader.swift
@@ -10,7 +10,7 @@ public class InMemoryReader {
 
   private let databaseContent: Data
   private let indexRange:      Range<Data.Index>
-  let metadata: Metadata
+  let metadata: MetadataStruct
 
   public init(data: Data) throws {
     databaseContent = data
diff --git a/Sources/MaxMindDBReader/Metadata.swift b/Sources/MaxMindDBReader/Metadata.swift
index c251390..db3988d 100644
--- a/Sources/MaxMindDBReader/Metadata.swift
+++ b/Sources/MaxMindDBReader/Metadata.swift
@@ -17,8 +17,3 @@ public protocol Metadata {
   var searchTreeSize:           UInt64 { get }
 
 }
-
-public extension Metadata {
-  var nodeByteSize:   UInt16 { get { return recordSize / 4 } }
-  var searchTreeSize: UInt64 { get { return UInt64(nodeCount * UInt32(nodeByteSize)) } }
-}
\ No newline at end of file
diff --git a/Sources/MaxMindDBReader/MetadataStruct.swift b/Sources/MaxMindDBReader/MetadataStruct.swift
index f10d8ce..6a965b2 100644
--- a/Sources/MaxMindDBReader/MetadataStruct.swift
+++ b/Sources/MaxMindDBReader/MetadataStruct.swift
@@ -1,7 +1,7 @@
 import Foundation
 import MaxMindDecoder
 
-struct MetadataStruct: Metadata {
+struct MetadataStruct {
   let nodeCount:                UInt32
   let recordSize:               UInt16
   let ipVersion:                UInt16
@@ -11,6 +11,8 @@ struct MetadataStruct: Metadata {
   let binaryFormatMinorVersion: UInt16
   let buildEpoch:               UInt64
   let description:              LanguageToDescription
+  var nodeByteSize:             UInt16 { get { return recordSize / 4 } }
+  var searchTreeSize:           UInt64 { get { return UInt64(nodeCount * UInt32(nodeByteSize)) } }
 
   init?(_ iterator: MaxMindIterator) {
     guard let mapControlByte = iterator.next() else { return nil }
diff --git a/Tests/MaxMindDBReaderTests/MetadataStructTest.swift b/Tests/MaxMindDBReaderTests/MetadataStructTest.swift
index fb8cdc7..aa93bdc 100644
--- a/Tests/MaxMindDBReaderTests/MetadataStructTest.swift
+++ b/Tests/MaxMindDBReaderTests/MetadataStructTest.swift
@@ -3,58 +3,17 @@ import XCTest
 @testable import MaxMindDBReader
 import MaxMindDecoder
 
-fileprivate struct MetadataTestImpl: Metadata {
-  let nodeCount:                UInt32
-  let recordSize:               UInt16
-  let ipVersion:                UInt16                = 4
-  let databaseType:             String                = ""
-  let languages:                [String]              = [""]
-  let binaryFormatMajorVersion: UInt16                = 1
-  let binaryFormatMinorVersion: UInt16                = 3
-  let buildEpoch:               UInt64                = 1588065718
-  let description:              LanguageToDescription = [:]
-}
-
 class MetadataStructTest: XCTestCase {
 
-  private func assertCalculatedValues(nodeCount: UInt32, recordSize: UInt16) {
-    let expectedNodeByteSize: UInt16 = recordSize / 4
-    let expectedSearchTreeSize       = UInt64(nodeCount * UInt32(expectedNodeByteSize))
-    XCTAssertEqual(
-      expectedNodeByteSize,
-      MetadataTestImpl(
-        nodeCount: nodeCount,
-        recordSize: recordSize
-      ).nodeByteSize
-    )
-    XCTAssertEqual(
-      expectedSearchTreeSize,
-      MetadataTestImpl(
-        nodeCount: nodeCount,
-        recordSize: recordSize
-      ).searchTreeSize
-    )
-  }
-
-  func testCalculatedValues() {
-    assertCalculatedValues(nodeCount: 3, recordSize: 3)
-    assertCalculatedValues(nodeCount: 3, recordSize: 10)
-    assertCalculatedValues(nodeCount: 3, recordSize: 100)
-    assertCalculatedValues(nodeCount: 3, recordSize: 1000)
-    assertCalculatedValues(nodeCount: 3, recordSize: 1000)
-    assertCalculatedValues(nodeCount: 3, recordSize: 10000)
-    assertCalculatedValues(nodeCount: 5, recordSize: 3)
-    assertCalculatedValues(nodeCount: 5, recordSize: 10)
-    assertCalculatedValues(nodeCount: 5, recordSize: 100)
-    assertCalculatedValues(nodeCount: 5, recordSize: 1000)
-    assertCalculatedValues(nodeCount: 5, recordSize: 1000)
-    assertCalculatedValues(nodeCount: 5, recordSize: 10000)
-    assertCalculatedValues(nodeCount: 500, recordSize: 3)
-    assertCalculatedValues(nodeCount: 500, recordSize: 10)
-    assertCalculatedValues(nodeCount: 500, recordSize: 100)
-    assertCalculatedValues(nodeCount: 500, recordSize: 1000)
-    assertCalculatedValues(nodeCount: 500, recordSize: 1000)
-    assertCalculatedValues(nodeCount: 500, recordSize: 10000)
+  private func assertCalculatedValues(
+    _ metadata: MetadataStruct,
+    file: StaticString = #file,
+    line: UInt = #line
+  ) {
+    let expectedNodeByteSize: UInt16 = metadata.recordSize / 4
+    let expectedSearchTreeSize       = UInt64(metadata.nodeCount * UInt32(expectedNodeByteSize))
+    XCTAssertEqual(expectedNodeByteSize, metadata.nodeByteSize, file: file, line: line)
+    XCTAssertEqual(expectedSearchTreeSize, metadata.searchTreeSize, file: file, line: line)
   }
 
   func testInit_nilIfCantCreateIterator() {
@@ -88,6 +47,7 @@ class MetadataStructTest: XCTestCase {
     XCTAssertEqual(["en": "GeoLite2 Country database"], metadata.description)
     XCTAssertEqual(6, metadata.nodeByteSize)
     XCTAssertEqual(3710754, metadata.searchTreeSize)
+    assertCalculatedValues(metadata)
   }
 
   func testInit_withIterator() {
@@ -111,6 +71,7 @@ class MetadataStructTest: XCTestCase {
     XCTAssertEqual(["en": "GeoLite2 Country database"], metadata.description)
     XCTAssertEqual(6, metadata.nodeByteSize)
     XCTAssertEqual(3710754, metadata.searchTreeSize)
+    assertCalculatedValues(metadata)
   }
 
 }