diff --git a/Package@swift-5.9.swift b/Package@swift-5.9.swift
index dbcd7c1b..697b4b3e 100644
--- a/Package@swift-5.9.swift
+++ b/Package@swift-5.9.swift
@@ -19,7 +19,7 @@ let package = Package(
     .library(
       name: "DependenciesMacros",
       targets: ["DependenciesMacros"]
-    )
+    ),
   ],
   dependencies: [
     .package(url: "https://github.com/apple/swift-syntax", from: "509.0.0"),
@@ -31,6 +31,13 @@ let package = Package(
     .package(url: "https://github.com/pointfreeco/xctest-dynamic-overlay", from: "1.0.0"),
   ],
   targets: [
+    .target(
+      name: "DependenciesTestObserver",
+      dependencies: [
+        "Dependencies",
+        .product(name: "XCTestDynamicOverlay", package: "xctest-dynamic-overlay"),
+      ]
+    ),
     .target(
       name: "Dependencies",
       dependencies: [
@@ -85,6 +92,16 @@ let package = Package(
   )
 #endif
 
+#if !os(macOS)
+package.products.append(
+  .library(
+    name: "DependenciesTestObserver",
+    type: .dynamic,
+    targets: ["DependenciesTestObserver"]
+  )
+)
+#endif
+
 //for target in package.targets {
 //  target.swiftSettings = target.swiftSettings ?? []
 //  target.swiftSettings?.append(
diff --git a/Sources/Dependencies/DependencyValues.swift b/Sources/Dependencies/DependencyValues.swift
index a73374f3..9db8fd3a 100644
--- a/Sources/Dependencies/DependencyValues.swift
+++ b/Sources/Dependencies/DependencyValues.swift
@@ -1,4 +1,23 @@
 import Foundation
+#if os(Windows)
+  import WinSDK
+#elseif os(Linux)
+  import Glibc
+#endif
+
+#if _runtime(_ObjC)
+extension DispatchQueue {
+  fileprivate static func mainSync<R>(execute block: @Sendable () -> R) -> R {
+    if Thread.isMainThread {
+      return block()
+    } else {
+      return Self.main.sync(execute: block)
+    }
+  }
+}
+
+final class TestObserver: NSObject {}
+#endif
 
 /// A collection of dependencies that is globally available.
 ///
@@ -86,7 +105,8 @@ public struct DependencyValues: Sendable {
   #endif
   @TaskLocal static var currentDependency = CurrentDependency()
 
-  fileprivate var cachedValues = CachedValues()
+  @_spi(DependenciesTestObserver)
+  public var cachedValues = CachedValues()
   private var storage: [ObjectIdentifier: AnySendable] = [:]
 
   /// Creates a dependency values instance.
@@ -95,8 +115,44 @@ public struct DependencyValues: Sendable {
   /// provide access only to default values. Instead, you rely on the dependency values' instance
   /// that the library manages for you when you use the ``Dependency`` property wrapper.
   public init() {
-    #if canImport(XCTest)
-      _ = setUpTestObservers
+    #if _runtime(_ObjC)
+      DispatchQueue.mainSync {
+        guard
+          let XCTestObservation = objc_getProtocol("XCTestObservation"),
+          let XCTestObservationCenter = NSClassFromString("XCTestObservationCenter"),
+          let XCTestObservationCenter = XCTestObservationCenter as Any as? NSObjectProtocol,
+          let XCTestObservationCenterShared =
+            XCTestObservationCenter
+            .perform(Selector(("sharedTestObservationCenter")))?
+            .takeUnretainedValue()
+        else { return }
+        let testCaseWillStartBlock: @convention(block) (AnyObject) -> Void = { _ in
+          DependencyValues._current.cachedValues.cached = [:]
+        }
+        let testCaseWillStartImp = imp_implementationWithBlock(testCaseWillStartBlock)
+        class_addMethod(
+          TestObserver.self, Selector(("testCaseWillStart:")), testCaseWillStartImp, nil)
+        class_addProtocol(TestObserver.self, XCTestObservation)
+        _ =
+          XCTestObservationCenterShared
+          .perform(Selector(("addTestObserver:")), with: TestObserver())
+      }
+    #else
+      typealias RegisterTestObserver = @convention(c) () -> Void
+      var pRegisterTestObserver: RegisterTestObserver? = nil
+
+      #if os(Windows)
+        let hModule = LoadLibraryA("DependenciesTestObserver.dll")
+        if let hModule, let pAddress = GetProcAddress(hModule, "registerTestObserver") {
+          pRegisterTestObserver = unsafeBitCast(pAddress, to: RegisterTestObserver.self)
+        }
+      #else
+        let hModule: UnsafeMutableRawPointer? = dlopen("libDependenciesTestObserver.so", RTLD_NOW)
+        if let hModule, let pAddress = dlsym(hModule, "_registerTestObserver") {
+          pRegisterTestObserver = unsafeBitCast(pAddress, to: RegisterTestObserver.self)
+        }
+      #endif
+      pRegisterTestObserver?()
     #endif
   }
 
@@ -207,8 +263,9 @@ public struct DependencyValues: Sendable {
   }
 }
 
-private struct AnySendable: @unchecked Sendable {
-  let base: Any
+@_spi(DependenciesTestObserver)
+public struct AnySendable: @unchecked Sendable {
+  public let base: Any
   @inlinable
   init<Base: Sendable>(_ base: Base) {
     self.base = base
@@ -257,14 +314,16 @@ private let defaultContext: DependencyContext = {
   }
 }()
 
-private final class CachedValues: @unchecked Sendable {
-  struct CacheKey: Hashable, Sendable {
+@_spi(DependenciesTestObserver)
+public final class CachedValues: @unchecked Sendable {
+  @_spi(DependenciesTestObserver)
+  public struct CacheKey: Hashable, Sendable {
     let id: ObjectIdentifier
     let context: DependencyContext
   }
 
   private let lock = NSRecursiveLock()
-  fileprivate var cached = [CacheKey: AnySendable]()
+  public var cached: [CacheKey: AnySendable] = [:]
 
   func value<Key: TestDependencyKey>(
     for key: Key.Type,
@@ -348,59 +407,3 @@ private final class CachedValues: @unchecked Sendable {
     return value
   }
 }
-
-// NB: We cannot statically link/load XCTest on Apple platforms, so we dynamically load things
-//     instead on platforms where XCTest is available.
-#if canImport(XCTest)
-  private let setUpTestObservers: Void = {
-    if _XCTIsTesting {
-      #if canImport(ObjectiveC)
-        DispatchQueue.mainSync {
-          guard
-            let XCTestObservation = objc_getProtocol("XCTestObservation"),
-            let XCTestObservationCenter = NSClassFromString("XCTestObservationCenter"),
-            let XCTestObservationCenter = XCTestObservationCenter as Any as? NSObjectProtocol,
-            let XCTestObservationCenterShared =
-              XCTestObservationCenter
-              .perform(Selector(("sharedTestObservationCenter")))?
-              .takeUnretainedValue()
-          else { return }
-          let testCaseWillStartBlock: @convention(block) (AnyObject) -> Void = { _ in
-            DependencyValues._current.cachedValues.cached = [:]
-          }
-          let testCaseWillStartImp = imp_implementationWithBlock(testCaseWillStartBlock)
-          class_addMethod(
-            TestObserver.self, Selector(("testCaseWillStart:")), testCaseWillStartImp, nil)
-          class_addProtocol(TestObserver.self, XCTestObservation)
-          _ =
-            XCTestObservationCenterShared
-            .perform(Selector(("addTestObserver:")), with: TestObserver())
-        }
-      #else
-        XCTestObservationCenter.shared.addTestObserver(TestObserver())
-      #endif
-    }
-  }()
-
-  #if canImport(ObjectiveC)
-    private final class TestObserver: NSObject {}
-
-    extension DispatchQueue {
-      fileprivate static func mainSync<R>(execute block: @Sendable () -> R) -> R {
-        if Thread.isMainThread {
-          return block()
-        } else {
-          return Self.main.sync(execute: block)
-        }
-      }
-    }
-  #else
-    import XCTest
-
-    private final class TestObserver: NSObject, XCTestObservation {
-      func testCaseWillStart(_ testCase: XCTestCase) {
-        DependencyValues._current.cachedValues.cached = [:]
-      }
-    }
-  #endif
-#endif
diff --git a/Sources/DependenciesTestObserver/TestObserver.swift b/Sources/DependenciesTestObserver/TestObserver.swift
new file mode 100644
index 00000000..bab49ad9
--- /dev/null
+++ b/Sources/DependenciesTestObserver/TestObserver.swift
@@ -0,0 +1,21 @@
+
+import XCTest
+@_spi(DependenciesTestObserver)
+import Dependencies
+import XCTestDynamicOverlay
+
+#if !_runtime(_ObjC)
+  public final class TestObserver: NSObject, XCTestObservation {
+    public func testCaseWillStart(_ testCase: XCTestCase) {
+      DependencyValues._current.cachedValues.cached = [:]
+    }
+  }
+#endif
+
+@_cdecl("registerTestObserver")
+public func registerTestObserver() {
+  guard _XCTIsTesting else { return }
+  #if !_runtime(_ObjC)
+    XCTestObservationCenter.shared.addTestObserver(TestObserver())
+  #endif
+}