Write tests that cover each branch and edge case. Test success paths, error paths, and boundary conditions.

• Tests that cover each branch
• Edge case

function processPayment(amount, method) {
  if (amount <= 0) return { success: false, error: 'Invalid amount' };
  if (method === 'credit') return { success: true, charge: amount };
  if (method === 'debit') return { success: true, charge: amount };
  return { success: false, error: 'Unknown method' };
}
// ...

• All code paths tested

• Identify every branch: if/else, switch cases, error conditions
• Test boundary values: 0, negative, max, min
• Aim for >80% code coverage; 100% branch coverage for critical code

Write tests that cover each branch and edge case. Test success paths, error paths, and boundary conditions.

• Tests that cover each branch
• Edge case

function processPayment(amount, method) {
  if (amount <= 0) return { success: false, error: 'Invalid amount' };
  if (method === 'credit') return { success: true, charge: amount };
  if (method === 'debit') return { success: true, charge: amount };
  return { success: false, error: 'Unknown method' };
}
// ...

• All code paths tested

• Identify every branch: if/else, switch cases, error conditions
• Test boundary values: 0, negative, max, min
• Aim for >80% code coverage; 100% branch coverage for critical code