Add AssertEqualEventually() and AssertTrueEventually test assertions (#2)

Author: atdrendel

README.md

@@ -11,7 +11,9 @@ The AsyncExtensions package also inlcudes the AsyncTestExtensions target, which
 ## AsyncTestExtensions includes
 
 - `AssertEqual()`
+- `AssertEqualEventually()`
 - `AssertTrue()`
+- `AssertTrueEventually()`
 - `AssertFalse()`
 - `AssertNil()`
 - `AssertNotNil()`

Sources/AsyncTestExtensions/Assertions.swift

@@ -100,3 +100,92 @@ public func AssertNoThrow<T>(
         XCTFail("\(message()): \(String(describing: error))", file: file, line: line)
     }
 }
+
+public func AssertEqualEventually<T: Equatable>(
+    _ expression1: @escaping @autoclosure () async throws -> T,
+    _ expression2: @escaping @autoclosure () async throws -> T,
+    _ timeout: TimeInterval = 5,
+    _ message: @escaping @autoclosure () -> String = "",
+    file: StaticString = #filePath,
+    line: UInt = #line
+) async {
+    do {
+        try await withThrowingTaskGroup(
+            of: Void.self
+        ) { (group: inout ThrowingTaskGroup<Void, Error>) in
+            _ = group.addTaskUnlessCancelled {
+                try await Task.sleep(nanoseconds: UInt64(timeout * Double(NSEC_PER_SEC)))
+                throw CancellationError()
+            }
+
+            _ = group.addTaskUnlessCancelled {
+                var expr1 = try await expression1()
+                var expr2 = try await expression2()
+
+                while expr1 != expr2 {
+                    try await Task.sleep(nanoseconds: 10 * NSEC_PER_MSEC)
+
+                    expr1 = try await expression1()
+                    expr2 = try await expression2()
+                }
+
+                XCTAssertEqual(expr1, expr2, message(), file: file, line: line)
+            }
+
+            _ = try await group.next()
+            group.cancelAll()
+        }
+    } catch is CancellationError {
+        do {
+            let expr1 = try await expression1()
+            let expr2 = try await expression2()
+            XCTAssertEqual(expr1, expr2, message(), file: file, line: line)
+        } catch {
+            XCTFail("\(message()): \(String(describing: error))", file: file, line: line)
+        }
+    } catch {
+        XCTFail("\(message()): \(String(describing: error))", file: file, line: line)
+    }
+}
+
+public func AssertTrueEventually(
+    _ expression1: @escaping @autoclosure () async throws -> Bool,
+    _ timeout: TimeInterval = 5,
+    _ message: @escaping @autoclosure () -> String = "",
+    file: StaticString = #filePath,
+    line: UInt = #line
+) async {
+    do {
+        try await withThrowingTaskGroup(
+            of: Void.self
+        ) { (group: inout ThrowingTaskGroup<Void, Error>) in
+            _ = group.addTaskUnlessCancelled {
+                try await Task.sleep(nanoseconds: UInt64(timeout * Double(NSEC_PER_SEC)))
+                throw CancellationError()
+            }
+
+            _ = group.addTaskUnlessCancelled {
+                var expr1 = try await expression1()
+
+                while !expr1 {
+                    try await Task.sleep(nanoseconds: 10 * NSEC_PER_MSEC)
+                    expr1 = try await expression1()
+                }
+
+                XCTAssertTrue(expr1, message(), file: file, line: line)
+            }
+
+            _ = try await group.next()
+            group.cancelAll()
+        }
+    } catch is CancellationError {
+        do {
+            let expr1 = try await expression1()
+            XCTAssertTrue(expr1, message(), file: file, line: line)
+        } catch {
+            XCTFail("\(message()): \(String(describing: error))", file: file, line: line)
+        }
+    } catch {
+        XCTFail("\(message()): \(String(describing: error))", file: file, line: line)
+    }
+}