Add unit tests for LoginButton component with comprehensive coverage

backend/utils/email_instance.py

@@ -1,3 +0,0 @@
-from utils.email_sender import EmailSender
-
-email_sender = EmailSender()

backend/utils/email_sender.py

@@ -1,65 +1,56 @@
-import os
 from flask import current_app
 from flask_mail import Mail, Message
-import smtplib
-from email.mime.text import MIMEText
 
-class EmailSender:
-    def __init__(self, app=None):
-        self.mail = None
-        if app is not None:
-            self.init_app(app)
+def send_verification_email(to_email: str, token: str) -> None:
+    verify_url = f"{current_app.config['FRONTEND_URL']}/auth/verify?token={token}"
+    html_body = f'Click <a href="{verify_url}">here</a> to verify your account.'
+    msg = Message(
+        subject="Verify your account",
+        recipients=[to_email],
+        html=html_body,
+        sender=current_app.config.get('MAIL_DEFAULT_SENDER', 'no-reply@reward-app.local')
+    )
+    try:
+        Mail(current_app).send(msg)
+        print(f"[EMAIL to {to_email}] Verification: {verify_url}")
+    except Exception:
+        print(f"Failed to send email to {to_email}. Verification link: {verify_url}")
 
-    def init_app(self, app):
-        self.mail = Mail(app)
+def send_reset_password_email(to_email: str, token: str) -> None:
+    reset_url = f"{current_app.config['FRONTEND_URL']}/auth/reset-password?token={token}"
+    html_body = f'Click <a href="{reset_url}">here</a> to reset your password.'
+    msg = Message(
+        subject="Reset your password",
+        recipients=[to_email],
+        html=html_body,
+        sender=current_app.config.get('MAIL_DEFAULT_SENDER', 'no-reply@reward-app.local')
+    )
+    try:
+        Mail(current_app).send(msg)
+        print(f"[EMAIL to {to_email}] Reset password: {reset_url}")
+    except Exception:
+        print(f"Failed to send email to {to_email}. Reset link: {reset_url}")
 
-    def send_verification_email(self, to_email, token):
-        verify_url = f"{current_app.config['FRONTEND_URL']}/auth/verify?token={token}"
-        html_body = f'Click <a href="{verify_url}">here</a> to verify your account.'
-        msg = Message(
-            subject="Verify your account",
-            recipients=[to_email],
-            html=html_body,
-            sender=current_app.config.get('MAIL_DEFAULT_SENDER', 'no-reply@reward-app.local')
-        )
-        if self.mail:
-            self.mail.send(msg)
-        else:
-            print(f"[EMAIL to {to_email}] Verification: {verify_url}")
-
-    def send_reset_password_email(self, to_email, token):
-        reset_url = f"{current_app.config['FRONTEND_URL']}/auth/reset-password?token={token}"
-        html_body = f'Click <a href="{reset_url}">here</a> to reset your password.'
-        msg = Message(
-            subject="Reset your password",
-            recipients=[to_email],
-            html=html_body,
-            sender=current_app.config.get('MAIL_DEFAULT_SENDER', 'no-reply@reward-app.local')
-        )
-        if self.mail:
-            self.mail.send(msg)
-        else:
-            print(f"[EMAIL to {to_email}] Reset password: {reset_url}")
-
-    def send_pin_setup_email(self, to_email, code):
-        html_body = f"""
-        <div style='font-family:sans-serif;'>
-          <h2>Set up your Parent PIN</h2>
-          <p>To set your Parent PIN, enter the following code in the app:</p>
-          <div style='font-size:2rem; font-weight:bold; letter-spacing:0.2em; margin:1.5rem 0;'>{code}</div>
-          <p>This code is valid for 10 minutes.</p>
-          <p>If you did not request this, you can ignore this email.</p>
-          <hr>
-          <div style='color:#888;font-size:0.95rem;'>Reward App</div>
-        </div>
-        """
-        msg = Message(
-            subject="Set up your Parent PIN",
-            recipients=[to_email],
-            html=html_body,
-            sender=current_app.config.get('MAIL_DEFAULT_SENDER', 'no-reply@reward-app.local')
-        )
-        if self.mail:
-            self.mail.send(msg)
-        else:
-            print(f"[EMAIL to {to_email}] Parent PIN setup code: {code}")
+def send_pin_setup_email(to_email: str, code: str) -> None:
+    html_body = f"""
+    <div style='font-family:sans-serif;'>
+      <h2>Set up your Parent PIN</h2>
+      <p>To set your Parent PIN, enter the following code in the app:</p>
+      <div style='font-size:2rem; font-weight:bold; letter-spacing:0.2em; margin:1.5rem 0;'>{code}</div>
+      <p>This code is valid for 10 minutes.</p>
+      <p>If you did not request this, you can ignore this email.</p>
+      <hr>
+      <div style='color:#888;font-size:0.95rem;'>Reward App</div>
+    </div>
+    """
+    msg = Message(
+        subject="Set up your Parent PIN",
+        recipients=[to_email],
+        html=html_body,
+        sender=current_app.config.get('MAIL_DEFAULT_SENDER', 'no-reply@reward-app.local')
+    )
+    try:
+        Mail(current_app).send(msg)
+        print(f"[EMAIL to {to_email}] Parent PIN setup code: {code}")
+    except Exception:
+        print(f"Failed to send email to {to_email}. Parent PIN setup code: {code}")