CLI Assert Mode

The rustmail assert subcommand starts an ephemeral SMTP server, waits for emails matching your criteria, and exits with code 0 (pass) or 1 (timeout/fail). No daemon required.

Usage

rustmail assert [OPTIONS]

Options

Flag	Default	Description
--timeout	30s	Maximum time to wait for matching emails
--min-count	1	Minimum number of matching emails required
--subject	—	Filter by subject substring
--sender	—	Filter by sender address substring
--recipient	—	Filter by recipient address substring
--smtp-port	1025	SMTP port to listen on

Examples

# Wait up to 30s for at least 1 email
rustmail assert

# Wait for 2 "Password Reset" emails within 60 seconds
rustmail assert --timeout=60s --min-count=2 --subject="Password Reset"

# Assert on sender
rustmail assert --sender=notifications@example.com --min-count=1

Exit Codes

Code	Meaning
0	Assertion passed — required emails were received
1	Assertion failed — timeout or criteria not met

How It Works

1. Starts an ephemeral SMTP server (in-memory, no database file)
2. Listens for incoming emails
3. Filters against your criteria (subject, sender, recipient)
4. Exits 0 as soon as --min-count matching emails arrive
5. Exits 1 if --timeout is reached first