Fix some iOS UI test flakes

src/objective-c/manual_tests/GrpcIosTestUITests/GrpcIosTestUITests.m

@@ -90,6 +90,15 @@ int const kNumIterations = 1;
   XCTAssert([testApp.staticTexts[@"Call failed"] waitForExistenceWithTimeout:kWaitTime]);
 }
 
+- (void)expectCallSuccessOrFailed {
+  NSDate *startTime = [NSDate date];
+  while (![testApp.staticTexts[@"Call done"] exists] &&
+         ![testApp.staticTexts[@"Call failed"] exists]) {
+    XCTAssertLessThan([[NSDate date] timeIntervalSinceDate:startTime], kWaitTime);
+    [NSThread sleepForTimeInterval:1];
+  }
+}
+
 - (void)setAirplaneMode:(BOOL)to {
   [settingsApp activate];
   XCUIElement *mySwitch = settingsApp.tables.element.cells.switches[@"Airplane Mode"];
@@ -118,13 +127,6 @@ int const kNumIterations = 1;
   [backButton tap];
 }
 
-- (void)typeText:(NSString *)text inApp:(XCUIApplication *)app {
-  [app typeText:text];
-  // Wait until all events in run loop have been processed
-  while (CFRunLoopRunInMode(kCFRunLoopDefaultMode, 0.1, true) == kCFRunLoopRunHandledSource)
-    ;
-}
-
 - (int)getRandomNumberBetween:(int)min max:(int)max {
   return min + arc4random_uniform((max - min + 1));
 }
@@ -216,24 +218,17 @@ int const kNumIterations = 1;
   // Send test app to background
   [XCUIDevice.sharedDevice pressButton:XCUIDeviceButtonHome];
 
-  // Open safari and goto a URL
-  XCUIApplication *safari =
-      [[XCUIApplication alloc] initWithBundleIdentifier:@"com.apple.mobilesafari"];
-  [safari activate];
-  // Ensure that safari is running in the foreground
-  XCTAssert([safari waitForState:XCUIApplicationStateRunningForeground timeout:5]);
-  // Move cursor to address bar
-  [safari.buttons[@"URL"] tap];
-  // Wait for keyboard to appear
-  [NSThread sleepForTimeInterval:2];
-  // Enter URL
-  [self typeText:@"http://maps.google.com" inApp:safari];
-  // Presses return key
-  [self typeText:@"\n" inApp:safari];
+  // Open stocks app
+  XCUIApplication *stocksApp =
+      [[XCUIApplication alloc] initWithBundleIdentifier:@"com.apple.stocks"];
+  [stocksApp activate];
+  // Ensure that stocks app is running in the foreground
+  XCTAssert([stocksApp waitForState:XCUIApplicationStateRunningForeground timeout:5]);
   // Wait a bit
   int sleepTime = [self getRandomNumberBetween:5 max:10];
   NSLog(@"Sleeping for %d seconds", sleepTime);
   [NSThread sleepForTimeInterval:sleepTime];
+  [stocksApp terminate];
 
   // Make another unary call
   [self doUnaryCall];
@@ -256,8 +251,13 @@ int const kNumIterations = 1;
   [self setWifi:YES];
 
   [testApp activate];
-  // We expect the call to have failed because the network flapped
-  [self expectCallFailed];
+  [self pressButton:@"Stop streaming call"];
+  // The call will fail if the stream gets a read error, else the call will succeed.
+  [self expectCallSuccessOrFailed];
+
+  // Make another unary call, it should succeed
+  [self doUnaryCall];
+  [self expectCallSuccess];
 }
 
 - (void)testConcurrentCalls {