Adds an implementation of the LoadError.notReady error

Source/Turbo/WebView/ScriptMessage.swift

@@ -54,6 +54,7 @@ extension ScriptMessage {
     enum Name: String {
         case pageLoaded
         case pageLoadFailed
+        case turboIsReady
         case errorRaised
         case visitProposed
         case visitProposalScrollingToAnchor

Source/Turbo/WebView/WebViewBridge.swift

@@ -112,6 +112,11 @@ extension WebViewBridge: ScriptMessageHandlerDelegate {
         switch message.name {
         case .pageLoaded:
             pageLoadDelegate?.webView(self, didLoadPageWithRestorationIdentifier: message.restorationIdentifier!)
+        case .turboIsReady:
+            let isReady = message.data["isReady"] as? Bool ?? false
+            if !isReady {
+                delegate?.webView(self, didFailInitialPageLoadWithError: .load(.notReady))
+            }
         case .pageLoadFailed:
             delegate?.webView(self, didFailInitialPageLoadWithError: .load(.notPresent))
         case .formSubmissionStarted:

Source/Turbo/WebView/turbo.js

@@ -11,8 +11,10 @@
     registerAdapter() {
       if (window.Turbo) {
         Turbo.registerAdapter(this)
+        this.turboIsReady(true)
       } else if (window.Turbolinks) {
         Turbolinks.controller.adapter = this
+        this.turboIsReady(true)
       } else {
         throw new Error("Failed to register the TurboNative adapter")
       }
@@ -30,6 +32,10 @@
        this.postMessageAfterNextRepaint("pageLoaded", { restorationIdentifier })
     }
 
+    turboIsReady(isReady) {
+      this.postMessage("turboIsReady", { isReady: isReady })
+    }
+
     pageLoadFailed() {
       this.postMessage("pageLoadFailed")
     }
@@ -231,6 +237,7 @@
 
     setTimeout(() => {
       if (!window.Turbo && !window.Turbolinks) {
+        window.turboNative.turboIsReady(false)
         window.turboNative.pageLoadFailed()
       }
     }, TURBO_LOAD_TIMEOUT)

Tests/Turbo/ScriptMessageTests.swift

@@ -37,6 +37,24 @@ class ScriptMessageTests: XCTestCase {
         let message = ScriptMessage(message: script)
         XCTAssertNil(message)
     }
+
+    func test_parse_turboIsReady_withFalse_returnsMessage() throws {
+        let data: [String: Any] = ["isReady": false, "timestamp": 0]
+        let script = FakeScriptMessage(body: ["name": "turboIsReady", "data": data] as [String: Any])
+
+        let message = try XCTUnwrap(ScriptMessage(message: script))
+        XCTAssertEqual(message.name, .turboIsReady)
+        XCTAssertEqual(message.data["isReady"] as? Bool, false)
+    }
+
+    func test_parse_turboIsReady_withTrue_returnsMessage() throws {
+        let data: [String: Any] = ["isReady": true, "timestamp": 0]
+        let script = FakeScriptMessage(body: ["name": "turboIsReady", "data": data] as [String: Any])
+
+        let message = try XCTUnwrap(ScriptMessage(message: script))
+        XCTAssertEqual(message.name, .turboIsReady)
+        XCTAssertEqual(message.data["isReady"] as? Bool, true)
+    }
 }
 
 // Can't instantiate a WKScriptMessage directly

Tests/Turbo/SessionTests.swift

@@ -95,15 +95,19 @@ class SessionTests: XCTestCase {
     }
 
     @MainActor
-    func test_coldBootVisit_whenVisitFailsFromMissingLibrary_providesAnPageLoadError() async throws {
-        await visit("/missing-library", timeout: turboTimeout + defaultTimeout)
+    func test_coldBootVisit_whenVisitFailsFromMissingLibrary_providesNotReadyAndNotPresentErrors() async throws {
+        let expectation = self.expectation(description: "Wait for both load errors.")
+        expectation.expectedFulfillmentCount = 2
+        sessionDelegate.didChange = { expectation.fulfill() }
 
-        XCTAssertTrue(sessionDelegate.sessionDidFailRequestCalled)
-        XCTAssertTrue(sessionDelegate.sessionDidFinishRequestCalled)
+        let visitable = TestVisitable(url: url("/missing-library"))
+        session.visit(visitable)
+        await fulfillment(of: [expectation], timeout: turboTimeout + defaultTimeout)
 
-        XCTAssertNotNil(sessionDelegate.failedRequestError)
-        let error = try XCTUnwrap(sessionDelegate.failedRequestError)
-        XCTAssertEqual(error, .load(.notPresent))
+        XCTAssertTrue(sessionDelegate.sessionDidFailRequestCalled)
+        XCTAssertEqual(sessionDelegate.allFailedRequestErrors.count, 2)
+        XCTAssertEqual(sessionDelegate.allFailedRequestErrors[0], .load(.notReady))
+        XCTAssertEqual(sessionDelegate.allFailedRequestErrors[1], .load(.notPresent))
     }
 
     // MARK: - Server

Tests/Turbo/Test.swift

@@ -55,6 +55,7 @@ class TestSessionDelegate: NSObject, SessionDelegate {
     var sessionDidStartRequestCalled = false
     var sessionDidFinishRequestCalled = false
     var failedRequestError: HotwireNativeError? = nil
+    var allFailedRequestErrors: [HotwireNativeError] = []
     var sessionDidFailRequestCalled = false { didSet { didChange?() }}
     var sessionDidProposeVisitCalled = false
     var sessionDidProposeVisitToCrossOriginRedirectWasCalled = false
@@ -83,6 +84,7 @@ class TestSessionDelegate: NSObject, SessionDelegate {
     func session(_ session: Session, didFailRequestForVisitable visitable: Visitable, error: HotwireNativeError) {
         sessionDidFailRequestCalled = true
         failedRequestError = error
+        allFailedRequestErrors.append(error)
     }
 
     func session(_ session: Session, didProposeVisit proposal: VisitProposal) {