diff --git a/Sources/XCTest/Public/XCNotificationExpectationHandler.swift b/Sources/XCTest/Public/Asynchronous/XCNotificationExpectationHandler.swift
similarity index 100%
rename from Sources/XCTest/Public/XCNotificationExpectationHandler.swift
rename to Sources/XCTest/Public/Asynchronous/XCNotificationExpectationHandler.swift
diff --git a/Sources/XCTest/Public/XCPredicateExpectationHandler.swift b/Sources/XCTest/Public/Asynchronous/XCPredicateExpectationHandler.swift
similarity index 100%
rename from Sources/XCTest/Public/XCPredicateExpectationHandler.swift
rename to Sources/XCTest/Public/Asynchronous/XCPredicateExpectationHandler.swift
diff --git a/Sources/XCTest/Public/XCTestCase+Asynchronous.swift b/Sources/XCTest/Public/Asynchronous/XCTestCase+Asynchronous.swift
similarity index 62%
rename from Sources/XCTest/Public/XCTestCase+Asynchronous.swift
rename to Sources/XCTest/Public/Asynchronous/XCTestCase+Asynchronous.swift
index 7380db7..b218614 100644
--- a/Sources/XCTest/Public/XCTestCase+Asynchronous.swift
+++ b/Sources/XCTest/Public/Asynchronous/XCTestCase+Asynchronous.swift
@@ -151,94 +151,6 @@
             completionHandler(error)
         }
     }
-
-    /// Creates and returns an expectation for a notification.
-    ///
-    /// - Parameter notificationName: The name of the notification the
-    ///   expectation observes.
-    /// - Parameter object: The object whose notifications the expectation will
-    ///   receive; that is, only notifications with this object are observed by
-    ///   the test case. If you pass nil, the expectation doesn't use
-    ///   a notification's object to decide whether it is fulfilled.
-    /// - Parameter handler: If provided, the handler will be invoked when the
-    ///   notification is observed. It will not be invoked on timeout. Use the
-    ///   handler to further investigate if the notification fulfills the
-    ///   expectation.
-    @discardableResult func expectation(forNotification notificationName: String, object objectToObserve: AnyObject?, handler: XCNotificationExpectationHandler? = nil) -> XCTestExpectation {
-        let objectDescription = objectToObserve == nil ? "any object" : "\(objectToObserve!)"
-        let expectation = self.expectation(description: "Expect notification '\(notificationName)' from " + objectDescription)
-        // Start observing the notification with specified name and object.
-        var observer: NSObjectProtocol? = nil
-        func removeObserver() {
-            if let observer = observer {
-                NotificationCenter.default.removeObserver(observer)
-            }
-        }
-
-        weak var weakExpectation = expectation
-        observer = NotificationCenter
-            .default
-            .addObserver(forName: Notification.Name(rawValue: notificationName),
-                                object: objectToObserve,
-                                queue: nil,
-                                usingBlock: {
-                                    notification in
-                                    guard let expectation = weakExpectation else {
-                                        removeObserver()
-                                        return
-                                    }
-
-                                    // If the handler is invoked, the test will
-                                    // only pass if true is returned.
-                                    if let handler = handler {
-                                        if handler(notification) {
-                                            expectation.fulfill()
-                                            removeObserver()
-                                        }
-                                    } else {
-                                        expectation.fulfill()
-                                        removeObserver()
-                                    }
-            })
-
-        return expectation
-    }
-
-    /// Creates and returns an expectation that is fulfilled if the predicate
-    /// returns true when evaluated with the given object. The expectation
-    /// periodically evaluates the predicate and also may use notifications or
-    /// other events to optimistically re-evaluate.
-    ///
-    /// - Parameter predicate: The predicate that will be used to evaluate the
-    ///   object.
-    /// - Parameter object: The object that is evaluated against the conditions
-    ///   specified by the predicate.
-    /// - Parameter file: The file name to use in the error message if
-    ///   this expectation is not waited for. Default is the file
-    ///   containing the call to this method. It is rare to provide this
-    ///   parameter when calling this method.
-    /// - Parameter line: The line number to use in the error message if the
-    ///   this expectation is not waited for. Default is the line
-    ///   number of the call to this method in the calling file. It is rare to
-    ///   provide this parameter when calling this method.
-    /// - Parameter handler: A block to be invoked when evaluating the predicate
-    ///   against the object returns true. If the block is not provided the
-    ///   first successful evaluation will fulfill the expectation. If provided,
-    ///   the handler can override that behavior which leaves the caller
-    ///   responsible for fulfilling the expectation.
-    @discardableResult func expectation(for predicate: NSPredicate, evaluatedWith object: AnyObject, file: StaticString = #file, line: UInt = #line, handler: XCPredicateExpectationHandler? = nil) -> XCTestExpectation {
-        let expectation = XCPredicateExpectation(
-            predicate: predicate,
-            object: object,
-            description: "Expect `\(predicate)` for object \(object)",
-            file: file,
-            line: line,
-            testCase: self,
-            handler: handler)
-        _allExpectations.append(expectation)
-        expectation.considerFulfilling()
-        return expectation
-    }
 }
 
 internal extension XCTestCase {
diff --git a/Sources/XCTest/Public/Asynchronous/XCTestCase+NotificationExpectation.swift b/Sources/XCTest/Public/Asynchronous/XCTestCase+NotificationExpectation.swift
new file mode 100644
index 0000000..92f8d0a
--- /dev/null
+++ b/Sources/XCTest/Public/Asynchronous/XCTestCase+NotificationExpectation.swift
@@ -0,0 +1,71 @@
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2015 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See http://swift.org/LICENSE.txt for license information
+// See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//
+//  XCTestCase+NotificationExpectation.swift
+//
+
+#if os(Linux) || os(FreeBSD)
+    import Foundation
+#else
+    import SwiftFoundation
+#endif
+
+public extension XCTestCase {
+    /// Creates and returns an expectation for a notification.
+    ///
+    /// - Parameter notificationName: The name of the notification the
+    ///   expectation observes.
+    /// - Parameter object: The object whose notifications the expectation will
+    ///   receive; that is, only notifications with this object are observed by
+    ///   the test case. If you pass nil, the expectation doesn't use
+    ///   a notification's object to decide whether it is fulfilled.
+    /// - Parameter handler: If provided, the handler will be invoked when the
+    ///   notification is observed. It will not be invoked on timeout. Use the
+    ///   handler to further investigate if the notification fulfills the
+    ///   expectation.
+    @discardableResult func expectation(forNotification notificationName: String, object objectToObserve: AnyObject?, handler: XCNotificationExpectationHandler? = nil) -> XCTestExpectation {
+        let objectDescription = objectToObserve == nil ? "any object" : "\(objectToObserve!)"
+        let expectation = self.expectation(description: "Expect notification '\(notificationName)' from " + objectDescription)
+        // Start observing the notification with specified name and object.
+        var observer: NSObjectProtocol? = nil
+        func removeObserver() {
+            if let observer = observer {
+                NotificationCenter.default.removeObserver(observer)
+            }
+        }
+
+        weak var weakExpectation = expectation
+        observer = NotificationCenter
+            .default
+            .addObserver(forName: Notification.Name(rawValue: notificationName),
+                         object: objectToObserve,
+                         queue: nil,
+                         usingBlock: {
+                            notification in
+                            guard let expectation = weakExpectation else {
+                                removeObserver()
+                                return
+                            }
+
+                            // If the handler is invoked, the test will
+                            // only pass if true is returned.
+                            if let handler = handler {
+                                if handler(notification) {
+                                    expectation.fulfill()
+                                    removeObserver()
+                                }
+                            } else {
+                                expectation.fulfill()
+                                removeObserver()
+                            }
+            })
+
+        return expectation
+    }
+}
diff --git a/Sources/XCTest/Public/Asynchronous/XCTestCase+PredicateExpectation.swift b/Sources/XCTest/Public/Asynchronous/XCTestCase+PredicateExpectation.swift
new file mode 100644
index 0000000..e282c78
--- /dev/null
+++ b/Sources/XCTest/Public/Asynchronous/XCTestCase+PredicateExpectation.swift
@@ -0,0 +1,55 @@
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2015 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See http://swift.org/LICENSE.txt for license information
+// See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//
+//  XCTestCase+PredicateExpectation.swift
+//
+
+#if os(Linux) || os(FreeBSD)
+    import Foundation
+#else
+    import SwiftFoundation
+#endif
+
+public extension XCTestCase {
+    /// Creates and returns an expectation that is fulfilled if the predicate
+    /// returns true when evaluated with the given object. The expectation
+    /// periodically evaluates the predicate and also may use notifications or
+    /// other events to optimistically re-evaluate.
+    ///
+    /// - Parameter predicate: The predicate that will be used to evaluate the
+    ///   object.
+    /// - Parameter object: The object that is evaluated against the conditions
+    ///   specified by the predicate.
+    /// - Parameter file: The file name to use in the error message if
+    ///   this expectation is not waited for. Default is the file
+    ///   containing the call to this method. It is rare to provide this
+    ///   parameter when calling this method.
+    /// - Parameter line: The line number to use in the error message if the
+    ///   this expectation is not waited for. Default is the line
+    ///   number of the call to this method in the calling file. It is rare to
+    ///   provide this parameter when calling this method.
+    /// - Parameter handler: A block to be invoked when evaluating the predicate
+    ///   against the object returns true. If the block is not provided the
+    ///   first successful evaluation will fulfill the expectation. If provided,
+    ///   the handler can override that behavior which leaves the caller
+    ///   responsible for fulfilling the expectation.
+    @discardableResult func expectation(for predicate: NSPredicate, evaluatedWith object: AnyObject, file: StaticString = #file, line: UInt = #line, handler: XCPredicateExpectationHandler? = nil) -> XCTestExpectation {
+        let expectation = XCPredicateExpectation(
+            predicate: predicate,
+            object: object,
+            description: "Expect `\(predicate)` for object \(object)",
+            file: file,
+            line: line,
+            testCase: self,
+            handler: handler)
+        _allExpectations.append(expectation)
+        expectation.considerFulfilling()
+        return expectation
+    }
+}
diff --git a/Sources/XCTest/Public/XCTestExpectation.swift b/Sources/XCTest/Public/Asynchronous/XCTestExpectation.swift
similarity index 100%
rename from Sources/XCTest/Public/XCTestExpectation.swift
rename to Sources/XCTest/Public/Asynchronous/XCTestExpectation.swift
diff --git a/Sources/XCTest/Public/XCWaitCompletionHandler.swift b/Sources/XCTest/Public/Asynchronous/XCWaitCompletionHandler.swift
similarity index 100%
rename from Sources/XCTest/Public/XCWaitCompletionHandler.swift
rename to Sources/XCTest/Public/Asynchronous/XCWaitCompletionHandler.swift
diff --git a/XCTest.xcodeproj/project.pbxproj b/XCTest.xcodeproj/project.pbxproj
index 1187787..a6a87fb 100644
--- a/XCTest.xcodeproj/project.pbxproj
+++ b/XCTest.xcodeproj/project.pbxproj
@@ -8,22 +8,17 @@
 
 /* Begin PBXBuildFile section */
 		AE2FE0FB1CFE86DB003EF0D7 /* XCAbstractTest.swift in Sources */ = {isa = PBXBuildFile; fileRef = AE2FE0EA1CFE86DB003EF0D7 /* XCAbstractTest.swift */; };
-		AE2FE0FC1CFE86DB003EF0D7 /* XCNotificationExpectationHandler.swift in Sources */ = {isa = PBXBuildFile; fileRef = AE2FE0EB1CFE86DB003EF0D7 /* XCNotificationExpectationHandler.swift */; };
-		AE2FE0FD1CFE86DB003EF0D7 /* XCPredicateExpectationHandler.swift in Sources */ = {isa = PBXBuildFile; fileRef = AE2FE0EC1CFE86DB003EF0D7 /* XCPredicateExpectationHandler.swift */; };
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-		AE2FE1001CFE86DB003EF0D7 /* XCTestCase+Asynchronous.swift in Sources */ = {isa = PBXBuildFile; fileRef = AE2FE0EF1CFE86DB003EF0D7 /* XCTestCase+Asynchronous.swift */; };
 		AE2FE1011CFE86DB003EF0D7 /* XCTestCase+Performance.swift in Sources */ = {isa = PBXBuildFile; fileRef = AE2FE0F01CFE86DB003EF0D7 /* XCTestCase+Performance.swift */; };
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 		AE2FE1031CFE86DB003EF0D7 /* XCTestErrors.swift in Sources */ = {isa = PBXBuildFile; fileRef = AE2FE0F21CFE86DB003EF0D7 /* XCTestErrors.swift */; };
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 		AE2FE1071CFE86DB003EF0D7 /* XCTestObservationCenter.swift in Sources */ = {isa = PBXBuildFile; fileRef = AE2FE0F61CFE86DB003EF0D7 /* XCTestObservationCenter.swift */; };
 		AE2FE1081CFE86DB003EF0D7 /* XCTestRun.swift in Sources */ = {isa = PBXBuildFile; fileRef = AE2FE0F71CFE86DB003EF0D7 /* XCTestRun.swift */; };
 		AE2FE1091CFE86DB003EF0D7 /* XCTestSuite.swift in Sources */ = {isa = PBXBuildFile; fileRef = AE2FE0F81CFE86DB003EF0D7 /* XCTestSuite.swift */; };
 		AE2FE10A1CFE86DB003EF0D7 /* XCTestSuiteRun.swift in Sources */ = {isa = PBXBuildFile; fileRef = AE2FE0F91CFE86DB003EF0D7 /* XCTestSuiteRun.swift */; };
-		AE2FE10B1CFE86DB003EF0D7 /* XCWaitCompletionHandler.swift in Sources */ = {isa = PBXBuildFile; fileRef = AE2FE0FA1CFE86DB003EF0D7 /* XCWaitCompletionHandler.swift */; };
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 		AE2FE1161CFE86E6003EF0D7 /* ObjectWrapper.swift in Sources */ = {isa = PBXBuildFile; fileRef = AE2FE10D1CFE86E6003EF0D7 /* ObjectWrapper.swift */; };
 		AE2FE1171CFE86E6003EF0D7 /* PerformanceMeter.swift in Sources */ = {isa = PBXBuildFile; fileRef = AE2FE10E1CFE86E6003EF0D7 /* PerformanceMeter.swift */; };
@@ -35,6 +30,13 @@
 		AE2FE11D1CFE86E6003EF0D7 /* XCTestInternalObservation.swift in Sources */ = {isa = PBXBuildFile; fileRef = AE2FE1141CFE86E6003EF0D7 /* XCTestInternalObservation.swift */; };
 		AE63767E1D01ED17002C0EA8 /* TestListing.swift in Sources */ = {isa = PBXBuildFile; fileRef = AE63767D1D01ED17002C0EA8 /* TestListing.swift */; };
 		DA7805FA1C6704A2003C6636 /* SwiftFoundation.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = DA7805F91C6704A2003C6636 /* SwiftFoundation.framework */; };
+		DA9D44191D920A3500108768 /* XCNotificationExpectationHandler.swift in Sources */ = {isa = PBXBuildFile; fileRef = DA9D44141D920A3500108768 /* XCNotificationExpectationHandler.swift */; };
+		DA9D441A1D920A3500108768 /* XCPredicateExpectationHandler.swift in Sources */ = {isa = PBXBuildFile; fileRef = DA9D44151D920A3500108768 /* XCPredicateExpectationHandler.swift */; };
+		DA9D441B1D920A3500108768 /* XCTestCase+Asynchronous.swift in Sources */ = {isa = PBXBuildFile; fileRef = DA9D44161D920A3500108768 /* XCTestCase+Asynchronous.swift */; };
+		DA9D441C1D920A3500108768 /* XCTestExpectation.swift in Sources */ = {isa = PBXBuildFile; fileRef = DA9D44171D920A3500108768 /* XCTestExpectation.swift */; };
+		DA9D441D1D920A3500108768 /* XCWaitCompletionHandler.swift in Sources */ = {isa = PBXBuildFile; fileRef = DA9D44181D920A3500108768 /* XCWaitCompletionHandler.swift */; };
+		DA9D441F1D920A5900108768 /* XCTestCase+PredicateExpectation.swift in Sources */ = {isa = PBXBuildFile; fileRef = DA9D441E1D920A5900108768 /* XCTestCase+PredicateExpectation.swift */; };
+		DA9D44211D920A6400108768 /* XCTestCase+NotificationExpectation.swift in Sources */ = {isa = PBXBuildFile; fileRef = DA9D44201D920A6400108768 /* XCTestCase+NotificationExpectation.swift */; };
 /* End PBXBuildFile section */
 
 /* Begin PBXContainerItemProxy section */
@@ -50,22 +52,17 @@
 /* Begin PBXFileReference section */
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-		AE2FE0EB1CFE86DB003EF0D7 /* XCNotificationExpectationHandler.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = XCNotificationExpectationHandler.swift; sourceTree = "<group>"; };
-		AE2FE0EC1CFE86DB003EF0D7 /* XCPredicateExpectationHandler.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = XCPredicateExpectationHandler.swift; sourceTree = "<group>"; };
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@@ -81,6 +78,13 @@
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+		DA9D44141D920A3500108768 /* XCNotificationExpectationHandler.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = XCNotificationExpectationHandler.swift; sourceTree = "<group>"; };
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+		DA9D44181D920A3500108768 /* XCWaitCompletionHandler.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = XCWaitCompletionHandler.swift; sourceTree = "<group>"; };
+		DA9D441E1D920A5900108768 /* XCTestCase+PredicateExpectation.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = "XCTestCase+PredicateExpectation.swift"; sourceTree = "<group>"; };
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 /* End PBXFileReference section */
 
@@ -138,23 +142,19 @@
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 			isa = PBXGroup;
 			children = (
+				DA9D44131D920A3500108768 /* Asynchronous */,
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-				AE2FE0F31CFE86DB003EF0D7 /* XCTestExpectation.swift */,
 				AE2FE0F41CFE86DB003EF0D7 /* XCTestMain.swift */,
 				AE2FE0F51CFE86DB003EF0D7 /* XCTestObservation.swift */,
 				AE2FE0F61CFE86DB003EF0D7 /* XCTestObservationCenter.swift */,
 				AE2FE0F71CFE86DB003EF0D7 /* XCTestRun.swift */,
 				AE2FE0F81CFE86DB003EF0D7 /* XCTestSuite.swift */,
 				AE2FE0F91CFE86DB003EF0D7 /* XCTestSuiteRun.swift */,
-				AE2FE0FA1CFE86DB003EF0D7 /* XCWaitCompletionHandler.swift */,
 			);
 			path = Public;
 			sourceTree = "<group>";
@@ -202,6 +202,20 @@
 			path = Tests;
 			sourceTree = "<group>";
 		};
+		DA9D44131D920A3500108768 /* Asynchronous */ = {
+			isa = PBXGroup;
+			children = (
+				DA9D44161D920A3500108768 /* XCTestCase+Asynchronous.swift */,
+				DA9D44171D920A3500108768 /* XCTestExpectation.swift */,
+				DA9D44181D920A3500108768 /* XCWaitCompletionHandler.swift */,
+				DA9D44151D920A3500108768 /* XCPredicateExpectationHandler.swift */,
+				DA9D441E1D920A5900108768 /* XCTestCase+PredicateExpectation.swift */,
+				DA9D44141D920A3500108768 /* XCNotificationExpectationHandler.swift */,
+				DA9D44201D920A6400108768 /* XCTestCase+NotificationExpectation.swift */,
+			);
+			path = Asynchronous;
+			sourceTree = "<group>";
+		};
 		EA3E74BC1BF2B6D700635A73 /* Linux Build */ = {
 			isa = PBXGroup;
 			children = (
@@ -314,32 +328,34 @@
 			buildActionMask = 2147483647;
 			files = (
 				AE2FE1071CFE86DB003EF0D7 /* XCTestObservationCenter.swift in Sources */,
-				AE2FE1001CFE86DB003EF0D7 /* XCTestCase+Asynchronous.swift in Sources */,
+				DA9D441C1D920A3500108768 /* XCTestExpectation.swift in Sources */,
 				AE2FE1011CFE86DB003EF0D7 /* XCTestCase+Performance.swift in Sources */,
+				DA9D441B1D920A3500108768 /* XCTestCase+Asynchronous.swift in Sources */,
 				AE2FE1181CFE86E6003EF0D7 /* PrintObserver.swift in Sources */,
 				AE2FE1021CFE86DB003EF0D7 /* XCTestCaseRun.swift in Sources */,
+				DA9D441D1D920A3500108768 /* XCWaitCompletionHandler.swift in Sources */,
+				DA9D441A1D920A3500108768 /* XCPredicateExpectationHandler.swift in Sources */,
 				AE2FE1171CFE86E6003EF0D7 /* PerformanceMeter.swift in Sources */,
 				AE2FE1051CFE86DB003EF0D7 /* XCTestMain.swift in Sources */,
 				AE2FE11B1CFE86E6003EF0D7 /* XCPredicateExpectation.swift in Sources */,
+				DA9D44191D920A3500108768 /* XCNotificationExpectationHandler.swift in Sources */,
+				DA9D44211D920A6400108768 /* XCTestCase+NotificationExpectation.swift in Sources */,
 				AE63767E1D01ED17002C0EA8 /* TestListing.swift in Sources */,
 				AE2FE1151CFE86E6003EF0D7 /* ArgumentParser.swift in Sources */,
 				AE2FE0FF1CFE86DB003EF0D7 /* XCTestCase.swift in Sources */,
+				DA9D441F1D920A5900108768 /* XCTestCase+PredicateExpectation.swift in Sources */,
 				AE2FE11D1CFE86E6003EF0D7 /* XCTestInternalObservation.swift in Sources */,
 				AE2FE1061CFE86DB003EF0D7 /* XCTestObservation.swift in Sources */,
-				AE2FE10B1CFE86DB003EF0D7 /* XCWaitCompletionHandler.swift in Sources */,
 				AE2FE0FB1CFE86DB003EF0D7 /* XCAbstractTest.swift in Sources */,
 				AE2FE1081CFE86DB003EF0D7 /* XCTestRun.swift in Sources */,
 				AE2FE10A1CFE86DB003EF0D7 /* XCTestSuiteRun.swift in Sources */,
-				AE2FE0FD1CFE86DB003EF0D7 /* XCPredicateExpectationHandler.swift in Sources */,
 				AE2FE1161CFE86E6003EF0D7 /* ObjectWrapper.swift in Sources */,
 				AE2FE11A1CFE86E6003EF0D7 /* WallClockTimeMetric.swift in Sources */,
 				AE2FE1191CFE86E6003EF0D7 /* TestFiltering.swift in Sources */,
-				AE2FE0FC1CFE86DB003EF0D7 /* XCNotificationExpectationHandler.swift in Sources */,
 				AE2FE1031CFE86DB003EF0D7 /* XCTestErrors.swift in Sources */,
 				AE2FE1091CFE86DB003EF0D7 /* XCTestSuite.swift in Sources */,
 				AE2FE11C1CFE86E6003EF0D7 /* XCTestCaseSuite.swift in Sources */,
 				AE2FE0FE1CFE86DB003EF0D7 /* XCTAssert.swift in Sources */,
-				AE2FE1041CFE86DB003EF0D7 /* XCTestExpectation.swift in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
diff --git a/build_script.py b/build_script.py
index 7d6ab90..334d5b4 100755
--- a/build_script.py
+++ b/build_script.py
@@ -10,7 +10,7 @@
 # See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
 
 import argparse
-import glob
+import fnmatch
 import os
 import subprocess
 import sys
@@ -39,6 +39,19 @@
         run("mkdir -p {}".format(path))
 
 
+def _find_files_with_extension(path, extension):
+    """
+    In Python 3.5 and above, glob supports recursive patterns such as
+    '**/*.swift'. This function backports that functionality to Python 3.4
+    and below.
+    """
+    paths = []
+    for root, _, file_names in os.walk(path):
+        for file_name in fnmatch.filter(file_names, '*.{}'.format(extension)):
+            paths.append(os.path.join(root, file_name))
+    return paths
+
+
 def symlink_force(target, link_name):
     if os.path.isdir(link_name):
         link_name = os.path.join(link_name, os.path.basename(target))
@@ -149,8 +162,9 @@
 
         _mkdirp(build_dir)
 
-        sourcePaths = glob.glob(os.path.join(
-            SOURCE_DIR, 'Sources', 'XCTest', '*', '*.swift'))
+        sourcePaths = _find_files_with_extension(
+                os.path.join(SOURCE_DIR, 'Sources', 'XCTest'),
+                'swift')
 
         if args.build_style == "debug":
             style_options = "-g"