Feature/handle multithreaded notifications

CONTRIBUTING.md

@@ -84,7 +84,7 @@ swift test
   by name.
 - Make sure your pull request includes any necessary updates to the
   README or other documentation.
-- Be sure the unit tests for both the OS X and iOS targets of Nimble
+- Be sure the unit tests for both the OS X and iOS targets of Nimble pass
   before submitting your pull request. You can run all the OS X & iOS unit
   tests using `./test`.
 - If you've added a file to the project, make sure it's included in both

Nimble.xcodeproj/project.pbxproj

@@ -284,6 +284,9 @@
 		472FD13B1B9E0CFE00C7B8DA /* HaveCountTest.swift in Sources */ = {isa = PBXBuildFile; fileRef = 472FD1361B9E094B00C7B8DA /* HaveCountTest.swift */; };
 		4793854D1BA0BB2500296F85 /* ObjCHaveCountTest.m in Sources */ = {isa = PBXBuildFile; fileRef = 4793854C1BA0BB2500296F85 /* ObjCHaveCountTest.m */; };
 		4793854E1BA0BB2500296F85 /* ObjCHaveCountTest.m in Sources */ = {isa = PBXBuildFile; fileRef = 4793854C1BA0BB2500296F85 /* ObjCHaveCountTest.m */; };
+		52F5CD6527EE571C00B19809 /* BackgroundThreadObject.swift in Sources */ = {isa = PBXBuildFile; fileRef = 52F5CD6427EE571C00B19809 /* BackgroundThreadObject.swift */; };
+		52F5CD6627EE571C00B19809 /* BackgroundThreadObject.swift in Sources */ = {isa = PBXBuildFile; fileRef = 52F5CD6427EE571C00B19809 /* BackgroundThreadObject.swift */; };
+		52F5CD6727EE571C00B19809 /* BackgroundThreadObject.swift in Sources */ = {isa = PBXBuildFile; fileRef = 52F5CD6427EE571C00B19809 /* BackgroundThreadObject.swift */; };
 		62FB326223B78BF90047BED9 /* BeginWithPrefix.swift in Sources */ = {isa = PBXBuildFile; fileRef = 62FB326123B78BF90047BED9 /* BeginWithPrefix.swift */; };
 		62FB326323B78BF90047BED9 /* BeginWithPrefix.swift in Sources */ = {isa = PBXBuildFile; fileRef = 62FB326123B78BF90047BED9 /* BeginWithPrefix.swift */; };
 		62FB326423B78BF90047BED9 /* BeginWithPrefix.swift in Sources */ = {isa = PBXBuildFile; fileRef = 62FB326123B78BF90047BED9 /* BeginWithPrefix.swift */; };
@@ -320,6 +323,7 @@
 		857D184F2536124400D8693A /* BeWithinTest.swift in Sources */ = {isa = PBXBuildFile; fileRef = 857D184D2536123F00D8693A /* BeWithinTest.swift */; };
 		857D18502536124400D8693A /* BeWithinTest.swift in Sources */ = {isa = PBXBuildFile; fileRef = 857D184D2536123F00D8693A /* BeWithinTest.swift */; };
 		857D18512536124500D8693A /* BeWithinTest.swift in Sources */ = {isa = PBXBuildFile; fileRef = 857D184D2536123F00D8693A /* BeWithinTest.swift */; };
+		8913626D29E5C2F500AD535E /* BackgroundThreadObject.swift in Sources */ = {isa = PBXBuildFile; fileRef = 52F5CD6427EE571C00B19809 /* BackgroundThreadObject.swift */; };
 		892FDF1329D3EA7700523A80 /* AsyncExpression.swift in Sources */ = {isa = PBXBuildFile; fileRef = 892FDF1229D3EA7700523A80 /* AsyncExpression.swift */; };
 		892FDF1429D3EA7700523A80 /* AsyncExpression.swift in Sources */ = {isa = PBXBuildFile; fileRef = 892FDF1229D3EA7700523A80 /* AsyncExpression.swift */; };
 		892FDF1529D3EA7700523A80 /* AsyncExpression.swift in Sources */ = {isa = PBXBuildFile; fileRef = 892FDF1229D3EA7700523A80 /* AsyncExpression.swift */; };
@@ -759,6 +763,7 @@
 		472FD1341B9E085700C7B8DA /* HaveCount.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = HaveCount.swift; sourceTree = "<group>"; };
 		472FD1361B9E094B00C7B8DA /* HaveCountTest.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = HaveCountTest.swift; sourceTree = "<group>"; };
 		4793854C1BA0BB2500296F85 /* ObjCHaveCountTest.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = ObjCHaveCountTest.m; sourceTree = "<group>"; };
+		52F5CD6427EE571C00B19809 /* BackgroundThreadObject.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = BackgroundThreadObject.swift; sourceTree = "<group>"; };
 		62FB326123B78BF90047BED9 /* BeginWithPrefix.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = BeginWithPrefix.swift; sourceTree = "<group>"; };
 		62FB326523B78D4A0047BED9 /* BeginWithPrefixTest.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = BeginWithPrefixTest.swift; sourceTree = "<group>"; };
 		6CAEDD091CAEA86F003F1584 /* LinuxSupport.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = LinuxSupport.swift; sourceTree = "<group>"; };
@@ -890,6 +895,7 @@
 				1F14FB63194180C5009F2A08 /* utils.swift */,
 				1F0648CB19639F5A001F9C46 /* ObjectWithLazyProperty.swift */,
 				898F28AF25D9F4C30052B8D0 /* AlwaysFailMatcher.swift */,
+				52F5CD6427EE571C00B19809 /* BackgroundThreadObject.swift */,
 			);
 			path = Helpers;
 			sourceTree = "<group>";
@@ -1724,6 +1730,7 @@
 				7B13BA111DD361EB00C9098C /* ObjCContainElementSatisfyingTest.m in Sources */,
 				1F925EF6195C147800ED456B /* BeCloseToTest.swift in Sources */,
 				106112C62251E13B000A5848 /* BeResultTest.swift in Sources */,
+				52F5CD6627EE571C00B19809 /* BackgroundThreadObject.swift in Sources */,
 				1F4A56791A3B32E3009E1637 /* ObjCBeGreaterThanOrEqualToTest.m in Sources */,
 				A8A3B6F6207329DD00E25A08 /* SatisfyAllOfTest.swift in Sources */,
 				AE7ADE491C80C00D00B94CD3 /* MatchErrorTest.swift in Sources */,
@@ -1874,6 +1881,7 @@
 				89F5E09D290C37B8001F9377 /* OnFailureThrowsTest.swift in Sources */,
 				1F5DF1A71BDCA10200C3A531 /* EqualTest.swift in Sources */,
 				106112C72251E13B000A5848 /* BeResultTest.swift in Sources */,
+				52F5CD6727EE571C00B19809 /* BackgroundThreadObject.swift in Sources */,
 				CD79C9AA1D2CC848004B6F9A /* ObjCBeLessThanOrEqualToTest.m in Sources */,
 				1F5DF1931BDCA10200C3A531 /* SynchronousTest.swift in Sources */,
 				CD79C9A11D2CC83B004B6F9A /* ObjCBeCloseToTest.m in Sources */,
@@ -2030,6 +2038,7 @@
 				7B13BA101DD361EA00C9098C /* ObjCContainElementSatisfyingTest.m in Sources */,
 				1F925EF7195C147800ED456B /* BeCloseToTest.swift in Sources */,
 				1F4A567A1A3B32E3009E1637 /* ObjCBeGreaterThanOrEqualToTest.m in Sources */,
+				52F5CD6527EE571C00B19809 /* BackgroundThreadObject.swift in Sources */,
 				A8A3B6F5207329DC00E25A08 /* SatisfyAllOfTest.swift in Sources */,
 				AE7ADE4A1C80C00D00B94CD3 /* MatchErrorTest.swift in Sources */,
 				1F4A568C1A3B3407009E1637 /* ObjCBeTrueTest.m in Sources */,
@@ -2135,6 +2144,7 @@
 			isa = PBXSourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				8913626D29E5C2F500AD535E /* BackgroundThreadObject.swift in Sources */,
 				D95F8945267EA1E8004B1B4D /* BeNilTest.swift in Sources */,
 				D95F8949267EA1E8004B1B4D /* MatchTest.swift in Sources */,
 				D95F8951267EA1EE004B1B4D /* utils.swift in Sources */,

Sources/Nimble/Matchers/PostNotification.swift

@@ -5,13 +5,15 @@ import Foundation
 
 internal class NotificationCollector {
     private(set) var observedNotifications: [Notification]
+    private(set) var observedNotificationDescriptions: [String]
     private let notificationCenter: NotificationCenter
     private let names: Set<Notification.Name>
     private var tokens: [NSObjectProtocol]
 
     required init(notificationCenter: NotificationCenter, names: Set<Notification.Name> = []) {
         self.notificationCenter = notificationCenter
         self.observedNotifications = []
+        self.observedNotificationDescriptions = []
         self.names = names
         self.tokens = []
     }
@@ -21,6 +23,7 @@ internal class NotificationCollector {
             return notificationCenter.addObserver(forName: name, object: nil, queue: nil) { [weak self] notification in
                 // linux-swift gets confused by .append(n)
                 self?.observedNotifications.append(notification)
+                self?.observedNotificationDescriptions.append(stringify(notification))
             }
         }
 
@@ -71,7 +74,7 @@ private func _postNotifications<Out>(
         if collector.observedNotifications.isEmpty {
             actualValue = "no notifications"
         } else {
-            actualValue = "<\(stringify(collector.observedNotifications))>"
+            actualValue = "<\(stringify(collector.observedNotificationDescriptions))>"
         }
 
         var result = try predicate.satisfies(collectorNotificationsExpression)

Tests/NimbleTests/Helpers/BackgroundThreadObject.swift

@@ -0,0 +1,14 @@
+import Foundation
+import Nimble
+
+// Simulates an object that *really* cares what thread it is run on.
+// Supposed to replicate what happens if a NSManagedObject ends up
+// in a notification and is picked up by Nimble
+class BackgroundThreadObject: CustomDebugStringConvertible {
+    var debugDescription: String {
+        if Thread.isMainThread {
+            fail("This notification was accessed on the main thread when it should have been handled on the thread it was received on")
+        }
+        return "BackgroundThreadObject"
+    }
+}

Tests/NimbleTests/Matchers/PostNotificationTest.swift

@@ -68,6 +68,46 @@ final class PostNotificationTest: XCTestCase {
             }
         }.toEventually(postNotifications(equal([testNotification]), from: notificationCenter))
     }
+
+    func testFailsWhenNotificationIsPostedUnexpectedly() {
+        let n1 = Notification(name: Notification.Name("Foo"), object: nil)
+        failsWithErrorMessage("expected to not equal <[\(n1)]>, got <[\(n1)]>") {
+            expect {
+                self.notificationCenter.post(n1)
+            }.toNot(postNotifications(equal([n1]), from: self.notificationCenter))
+        }
+    }
+
+    func testPassesWhenNotificationIsNotPosted() {
+        let n1 = Notification(name: Notification.Name("Foo"), object: nil)
+        let n2 = Notification(name: Notification.Name(n1.name.rawValue + "a"), object: nil)
+        expect {
+            self.notificationCenter.post(n2)
+        }.toNever(postNotifications(equal([n1]), from: self.notificationCenter))
+    }
+
+    func testPassesWhenNotificationIsPostedFromADifferentThread() {
+        let n1 = Notification(name: Notification.Name("Foo"), object: nil)
+        expect {
+            OperationQueue().addOperations([BlockOperation {
+                let backgroundThreadObject = BackgroundThreadObject()
+                let n2 = Notification(name: Notification.Name("Bar"), object: backgroundThreadObject)
+                self.notificationCenter.post(n2)
+            }], waitUntilFinished: true)
+            self.notificationCenter.post(n1)
+        }.to(postNotifications(contain([n1]), from: notificationCenter))
+    }
+
+    func testPassesWhenNotificationIsPostedFromADifferentThreadAndToNotCalled() {
+        let n1 = Notification(name: Notification.Name("Foo"), object: nil)
+        expect {
+            OperationQueue().addOperations([BlockOperation {
+                let backgroundThreadObject = BackgroundThreadObject()
+                let n2 = Notification(name: Notification.Name(n1.name.rawValue + "a"), object: backgroundThreadObject)
+                self.notificationCenter.post(n2)
+            }], waitUntilFinished: true)
+        }.toNot(postNotifications(equal([n1]), from: notificationCenter))
+    }
 
     #if os(macOS)
     func testPassesWhenAllExpectedNotificationsarePostedInDistributedNotificationCenter() {