Test cases for SMS OTP login with a mobile number

1. Enter a registered 10-digit mobile number and tap Get OTP
2. Open the SMS when it arrives and type the code
3. Tap Verify, then repeat with numbers on Jio, Airtel and Vi

Expected: The OTP screen shows the number the code was sent to, and Verify opens the home screen for that account. The SMS arrives on all three carriers.

Why a real phone: Checks real SMS delivery from the OTP provider to live SIMs on each carrier.

1. Install the build from a Play Store testing track, not a debug build
2. Enter a registered number and tap Get OTP
3. Wait without touching the OTP field

Expected: The code fills by itself and verification starts without typing or any permission prompt. The home screen opens.

Why a real phone: The real SMS must carry the hash that matches the store-signed build.

1. Use a build that reads the OTP through the Android consent prompt
2. Request an OTP on a Jio SIM and tap Allow on the prompt
3. Repeat on Airtel and Vi SIMs

Expected: On each carrier the system prompt shows the OTP message, and tapping Allow fills the code.

Why a real phone: SMS sender headers differ by carrier and region, which an emulator cannot reproduce.

1. On an iPhone, request an OTP and tap the first digit box
2. Tap the code suggested above the keyboard when the SMS arrives

Expected: All digit boxes fill with the code, not just the first one, and verification starts or Verify becomes active.

Why a real phone: The iOS Simulator cannot receive SMS, so code suggestions need a real iPhone.

1. Request an OTP and watch the resend countdown
2. Tap Resend while the countdown is still running
3. Tap Resend after the countdown reaches zero

Expected: Resend stays disabled until the countdown ends, then sends a new code and restarts the countdown. A message confirms the code was sent again.

1. Request an OTP and wait until the app offers another channel, such as a call
2. Choose the call option and answer the incoming call
3. Enter the code read out on the call and tap Verify

Expected: The code arrives on the chosen channel for the entered number and signs in. If the SMS arrives later, it does not replace the code already entered.

Why a real phone: Needs a real call or message from the OTP service to a live number.

1. Enter 9 digits and tap Get OTP
2. Try to enter 11 digits
3. Paste text containing letters into the number field

Expected: The field stops at 10 digits or shows an inline error, and Get OTP stays disabled for invalid input. Letters are not accepted.

1. Request an OTP and enter a different code
2. Tap Verify and read the message
3. Enter the correct code and tap Verify

Expected: An error says the code is wrong and, if the app shows it, how many attempts remain. The correct code entered next signs in.

1. Enter wrong codes until the configured attempt limit is reached
2. Enter the correct code from the SMS
3. Reinstall the app and try the same number again

Expected: The correct code no longer signs in once the limit is reached, and the message says when to try again or to request a new code. Reinstalling does not reset the block.

1. Request an OTP and leave the screen open past the configured validity
2. Enter the code from the SMS and tap Verify

Expected: A message says the code has expired and offers Resend. The expired code does not sign in.

1. Request an OTP on a build that uses the consent prompt
2. Tap Deny when the prompt appears
3. Type the code manually and tap Verify

Expected: The prompt closes and does not reappear for the same SMS. The typed code signs in.

1. In a weak-signal spot, request an OTP and tap Resend twice when allowed
2. Note the order in which the SMS messages arrive
3. Enter the code from the last SMS to arrive

Expected: The code from the latest request signs in. An older code is rejected with a message pointing to the newest SMS, and auto-read does not replace a newer code with an older one.

Why a real phone: Out-of-order delivery happens on real carrier routes under load or weak signal.

1. Request an OTP and type the code from the notification quickly
2. Tap Verify at the moment auto-read fills the field
3. Repeat, this time double-tapping Verify

Expected: Only one verification runs and the home screen opens once. No 'code already used' or 'invalid OTP' error appears afterwards.

1. Request an OTP and check the SMS for other numbers, such as validity or a reference
2. Let auto-read fill the field, or paste the whole SMS into it

Expected: The field gets only the OTP digits, never the validity minutes or a reference number.

Why a real phone: Depends on the exact SMS text the provider sends to a real SIM.

1. Request an OTP for number A
2. Tap Change number, enter number B and request an OTP
3. Enter the code sent to number A and tap Verify

Expected: The OTP screen now shows number B with a fresh countdown. The code sent to number A is rejected.

1. Paste a contact's number saved as +91, a space and 10 digits
2. Paste the same number with a leading 0 instead of +91
3. Tap Get OTP each time

Expected: The field shows the plain 10-digit number each time and the OTP screen shows it correctly. No 'invalid number' error appears and +91 is not added twice.

1. Copy the code from the SMS or its notification
2. Long-press the first digit box and tap Paste
3. Repeat with the code copied with a space before it

Expected: All boxes fill with the digits in order and the space is ignored. Paste is offered on the digit boxes, not blocked.

1. Request an OTP and note the countdown
2. Switch to another app for longer than the countdown
3. Return to the app

Expected: The countdown has finished and Resend is available. It does not resume from where it was when the app was left.

1. Request an OTP in a spot where SMS is slow, such as a basement
2. Let the countdown finish without tapping Resend
3. Enter the code when the SMS finally arrives

Expected: The late code signs in because no newer code was requested. The screen has not moved away from OTP entry.

Why a real phone: Depends on real SMS delays on Jio, Airtel or Vi routes.

1. Request an OTP, then turn mobile data off before the SMS arrives
2. Enter the code and tap Verify
3. Turn data back on and tap Verify again

Expected: A no-connection message appears and the code stays in the field. The retry signs in and the failed try is not counted as a wrong attempt.

1. Request an OTP
2. Answer an incoming call and stay on it until the SMS arrives
3. End the call and return to the app

Expected: The OTP screen still shows the same number and the countdown has moved on. Auto-read fills the code, or it can be typed.

Why a real phone: Call screens on OEM skins pause the app differently from emulator calls.

1. On a 3–4 GB RAM phone, open a few heavy apps
2. Request an OTP and switch to the messages app to read it
3. Return to the app from the recent apps screen

Expected: The OTP screen reopens for the same number with the countdown intact, and the code from the SMS signs in. No new OTP is sent automatically.

Why a real phone: OEM memory managers on budget phones kill backgrounded apps far more often than emulators.

1. Set the phone to 2G only, or move to a weak-signal spot
2. Enter a number and tap Get OTP
3. Tap Get OTP again while it is loading

Expected: A loading state shows and Get OTP stays disabled until the request finishes or fails with a retry message. The OTP screen opens only once.

1. On a dual-SIM phone, set mobile data to SIM 1
2. Enter the SIM 2 number and tap Get OTP
3. Wait for the SMS on SIM 2

Expected: The code that arrives on SIM 2 is auto-read or can be typed, and it signs in. The app does not ask to switch SIMs or use the SIM 1 number.

Why a real phone: Needs a phone with two live SIMs; emulators have no dual-SIM radio.

1. On a dual-SIM phone, tap the mobile number field
2. Check the number suggestions offered by the phone
3. Pick the second SIM's number, or dismiss the suggestions

Expected: The picked number fills as 10 digits without a doubled +91. If nothing is suggested or the suggestions are dismissed, the field stays open for typing.

Why a real phone: Suggestions come from the real SIMs, and some SIMs do not report their number.

1. Use a keyboard that suggests codes from SMS, such as the phone maker's default
2. Request an OTP and tap the keyboard's code suggestion as soon as it appears
3. Let the app's auto-read run at the same time

Expected: The field holds the code once, with no doubled or extra digits. Verification runs only once.

Why a real phone: Code suggestions come from OEM keyboards reading a real incoming SMS.

1. On Xiaomi, Vivo and Samsung phones, use the default messages app
2. Request an OTP and watch for the notification
3. Open the messages app and find the SMS

Expected: A notification shows when the SMS arrives, and the message is in the inbox or the OTP category, not in spam or blocked messages.

Why a real phone: Each phone maker's messages app filters and groups SMS in its own way.

1. On a Jio, Airtel or Vi test SIM, turn on the carrier's full do-not-disturb preference
2. Wait until the carrier confirms the preference is active
3. Request an OTP for that number

Expected: The OTP SMS arrives as it does for numbers without the preference. It takes no longer than on the other test SIMs.

Why a real phone: Carrier filtering of promotional messages applies only to real SIMs.

1. Use a phone without Google Play services, or one where it is out of date
2. Request an OTP and open the OTP screen
3. Type the code from the SMS and tap Verify

Expected: The OTP screen opens without a crash or an error about auto-read. The typed code signs in.

1. Log in with an OTP and note the code
2. Sign out, enter the same number and tap Get OTP
3. Enter the earlier code instead of the new one

Expected: The earlier code is rejected. Only the newly sent code signs in.

1. Request an OTP and tap Resend each time it unlocks
2. Go back, re-enter the number and request again several times
3. Reinstall the app and request again

Expected: After the configured number of requests, the app shows a message saying when the user can try again. Going back or reinstalling does not reset the limit.

1. Enter a number that has no account and tap Get OTP
2. Enter a registered number and tap Get OTP
3. Compare the screens and messages

Expected: Both numbers reach the same OTP step with the same wording. Whether an account exists is shown only after the code is verified.

1. Request an OTP and leave the countdown running
2. Turn off automatic time and move the phone clock forward
3. Return to the app and tap Resend

Expected: Resend stays locked until the real wait has passed, or the request is refused with a message to wait.

1. Request an OTP
2. Before it arrives, have someone send the phone an SMS containing a code-like number
3. Wait for the real OTP SMS

Expected: The other SMS does not fill the field. Only the OTP message is auto-read or offered in the consent prompt.

1. Turn on TalkBack and open the OTP screen
2. Swipe through the digit boxes and the Resend control
3. Enter a wrong code and listen

Expected: The boxes are read as one code field or with their position, and the error is read out. The countdown is not announced every second, and Resend is read as unavailable until it ends.

1. Set font size and display size to the largest in phone Settings
2. Open the OTP screen on a small phone with the keyboard up

Expected: All digit boxes fit on one row or wrap readably, with no clipped digits. Resend and Verify can be reached without closing the keyboard.

1. Set the app language to Hindi, if the OTP SMS follows it
2. Request an OTP and open the SMS
3. Let auto-read fill the code

Expected: The SMS arrives as one message with readable Hindi text and the code intact. Auto-read fills the code as it does for the English SMS.

Why a real phone: Unicode SMS splitting and joining happen on the real carrier route and phone.

1. Set a Hindi keyboard as the default
2. Tap the OTP field and type the code using Devanagari digits
3. Tap Verify

Expected: The keyboard opens in number mode, or Devanagari digits are converted to 0–9 and the code signs in. A correct code typed this way is not rejected as invalid.