Disable submit on empty string

DuckDuckGo/NetworkProtectionInviteView.swift

@@ -60,7 +60,7 @@ struct NetworkProtectionInviteView: View {
             }, label: {
                 Text(UserText.appTPReportSubmit)
             })
-            .buttonStyle(PrimaryButtonStyle())
+            .buttonStyle(PrimaryButtonStyle(disabled: model.shouldDisableSubmit))
             .frame(height: 30)
         }
         .alert(isPresented: $model.shouldShowAlert) {

DuckDuckGo/NetworkProtectionInviteViewModel.swift

@@ -32,11 +32,13 @@ final class NetworkProtectionInviteViewModel: ObservableObject {
         didSet {
             if oldValue != text {
                 text = text.uppercased()
+                shouldDisableSubmit = text.count == 0
             }
         }
     }
     var errorText: String = ""
     @Published var shouldShowAlert: Bool = false
+    @Published var shouldDisableSubmit: Bool = true
 
     private let redemptionCoordinator: NetworkProtectionCodeRedeeming
     private let completion: () -> Void

DuckDuckGoTests/NetworkProtectionInviteViewModelTests.swift

@@ -25,11 +25,25 @@ import NetworkProtectionTestUtils
 final class NetworkProtectionInviteViewModelTests: XCTestCase {
 
     func test_text_alwaysUppercased() {
-        let viewModel = viewModel(withInjectedRedemptionCoordinator: .stubbed())
+        let viewModel = viewModel()
         viewModel.text = "abcdefg"
         XCTAssertEqual(viewModel.text, "ABCDEFG")
     }
 
+    func test_text_emptyString_disableSubmit() {
+        let viewModel = viewModel()
+        viewModel.text = ""
+        XCTAssertTrue(viewModel.shouldDisableSubmit)
+    }
+
+    func test_text_nonEmptyString_enableSubmit() {
+        let viewModel = viewModel()
+        for _ in 0..<5 {
+            viewModel.text.append("D")
+            XCTAssertFalse(viewModel.shouldDisableSubmit)
+        }
+    }
+
     func test_submit_successfulRedemption_changesCurrentStepToSuccess() async {
         let viewModel = viewModel(withInjectedRedemptionCoordinator: .whereRedeemSucceeds())
         await viewModel.submit()
@@ -68,7 +82,7 @@ final class NetworkProtectionInviteViewModelTests: XCTestCase {
         XCTAssertTrue(didCallCompletion)
     }
 
-    private func viewModel(withInjectedRedemptionCoordinator coordinator: NetworkProtectionCodeRedemptionCoordinator, completion: @escaping () -> Void = {}) -> NetworkProtectionInviteViewModel {
+    private func viewModel(withInjectedRedemptionCoordinator coordinator: NetworkProtectionCodeRedemptionCoordinator = .stubbed(), completion: @escaping () -> Void = {}) -> NetworkProtectionInviteViewModel {
         NetworkProtectionInviteViewModel(redemptionCoordinator: coordinator, completion: completion)
     }
 }