test: Ensure test is server running

Tests/SentryTests/Integrations/Performance/Network/SentryNetworkTrackerIntegrationTestServerTests.swift

@@ -10,12 +10,18 @@ import XCTest
 class SentryNetworkTrackerIntegrationTestServerTests: XCTestCase {
 
     func testGetRequest_SpanCreatedAndBaggageHeaderAdded() throws {
+        try ensureTestServerIsRunning()
+
         let testBaggageURL = try XCTUnwrap(URL(string: "http://localhost:8080/echo-baggage-header"))
 
         startSDK()
 
         let transaction = try XCTUnwrap(SentrySDK.startTransaction(name: "Test Transaction", operation: "TEST", bindToScope: true) as? SentryTracer)
+
         let expect = expectation(description: "Request completed")
+        // Cancelling the task in defer can trigger the completion handler again.
+        expect.assertForOverFulfill = false
+
         let session = URLSession(configuration: URLSessionConfiguration.default)
 
         let dataTask = session.dataTask(with: testBaggageURL) { (data, _, error) in
@@ -28,8 +34,10 @@ class SentryNetworkTrackerIntegrationTestServerTests: XCTestCase {
             expect.fulfill()
         }
 
+        defer { dataTask.cancel() }
+
         dataTask.resume()
-        wait(for: [expect], timeout: 5)
+        wait(for: [expect], timeout: 10)
 
         let children = try XCTUnwrap(Dynamic(transaction).children as [Span]?)
 
@@ -43,12 +51,18 @@ class SentryNetworkTrackerIntegrationTestServerTests: XCTestCase {
     }
 
     func testGetRequest_CompareSentryTraceHeader() throws {
+        try ensureTestServerIsRunning()
+
         let testTraceURL = try XCTUnwrap(URL(string: "http://localhost:8080/echo-sentry-trace"))
 
         startSDK()
 
         let transaction = try XCTUnwrap(SentrySDK.startTransaction(name: "Test Transaction", operation: "TEST", bindToScope: true) as? SentryTracer)
+
         let expect = expectation(description: "Request completed")
+        // Cancelling the task in defer can trigger the completion handler again.
+        expect.assertForOverFulfill = false
+
         let session = URLSession(configuration: URLSessionConfiguration.default)
         var response: String?
         let dataTask = session.dataTask(with: testTraceURL) { (data, _, error) in
@@ -57,8 +71,10 @@ class SentryNetworkTrackerIntegrationTestServerTests: XCTestCase {
             expect.fulfill()
         }
 
+        defer { dataTask.cancel() }
+
         dataTask.resume()
-        wait(for: [expect], timeout: 5)
+        wait(for: [expect], timeout: 10)
 
         let children = Dynamic(transaction).children as [SentrySpan]?
 
@@ -70,9 +86,14 @@ class SentryNetworkTrackerIntegrationTestServerTests: XCTestCase {
     }
 
     func testGetCaptureFailedRequestsEnabled() throws {
+        try ensureTestServerIsRunning()
+
         let clientErrorTraceURL = try XCTUnwrap(URL(string: "http://localhost:8080/http-client-error"))
 
         let expect = expectation(description: "Request completed")
+        expect.expectedFulfillmentCount = 2
+        // Cancelling the task in defer can trigger the completion handler again.
+        expect.assertForOverFulfill = false
 
         var sentryEvent: Event?
 
@@ -90,17 +111,21 @@ class SentryNetworkTrackerIntegrationTestServerTests: XCTestCase {
 
         let dataTask = session.dataTask(with: clientErrorTraceURL) { (_, _, error) in
             self.assertNetworkError(error)
+            expect.fulfill()
         }
 
+        defer { dataTask.cancel() }
+
         dataTask.resume()
-        wait(for: [expect], timeout: 5)
+        wait(for: [expect], timeout: 10)
 
         XCTAssertNotNil(sentryEvent)
         XCTAssertNotNil(sentryEvent?.request)
 
-        let sentryResponse = sentryEvent?.context?["response"]
+        let sentryResponse = try XCTUnwrap(sentryEvent?.context?["response"], "Expected context.response, but was nil")
+        let statusCode = try XCTUnwrap(sentryResponse["status_code"] as? NSNumber, "Expected context.response.status_code, but was nil")
 
-        XCTAssertEqual(sentryResponse?["status_code"] as? NSNumber, 400)
+        XCTAssertEqual(statusCode, 400)
     }
 
     private func assertNetworkError(_ error: Error?) {
@@ -109,6 +134,51 @@ class SentryNetworkTrackerIntegrationTestServerTests: XCTestCase {
         }
     }
 
+    // We can't use a XCTTestExpectation here because we want to retry multiple times.
+    // If a XCTestExpectation times out, the test would fail.
+    // swiftlint:disable avoid_dispatch_groups_in_tests
+    private func ensureTestServerIsRunning() throws {
+        let testUrl = try XCTUnwrap(URL(string: "http://localhost:8080/"))
+
+        let session = URLSession(configuration: URLSessionConfiguration.default)
+        let attempts = 20
+
+        //swiftlint:disable:next for_where
+        for attempt in 1..<attempts {
+            let group = DispatchGroup()
+            var isReady = false
+
+            group.enter()
+            let dataTask = session.dataTask(with: testUrl) { (_, response, error) in
+                if error == nil, let httpResponse = response as? HTTPURLResponse, httpResponse.statusCode == 200 {
+                    isReady = true
+                }
+                group.leave()
+            }
+
+            defer { dataTask.cancel() }
+
+            dataTask.resume()
+
+            // We don't care about the result, we just want to wait up to 2 seconds for the request to complete.
+            // If it doesn't work we retry.
+            _ = group.wait(timeout: .now() + 2)
+
+            if isReady {
+                print("Test server is ready after \(attempt) attempt(s)")
+                return
+            }
+
+            if attempt < 10 {
+                print("Test server not ready, retrying in 1 second... (attempt \(attempt)/10)")
+                Thread.sleep(forTimeInterval: 1.0)
+            }
+        }
+
+        XCTFail("Test server failed to become ready after \(attempts) attempts")
+    }
+    // swiftlint:enable avoid_dispatch_groups_in_tests
+
     private func startSDK(function: String = #function, _ configureOptions: ((Options) -> Void)? = nil) {
         let options = Options()
         options.dsn = TestConstants.dsnAsString(username: "SentryNetworkTrackerIntegrationTestServerTests.\(function)")