forge-vesting — add test verifying initialize() with total_amount = 0 returns InvalidConfig

[Austinaminu2]

Summary

initialize() validates total_amount <= 0 but the existing test_invalid_config_rejected only tests cliff > duration. There is no test explicitly covering the total_amount = 0 and total_amount = -1 cases which are the other two InvalidConfig branches.

Tasks

• Test initialize() with total_amount = 0 — assert Err(VestingError::InvalidConfig)
• Test initialize() with total_amount = -1 — assert Err(VestingError::InvalidConfig)
• Test initialize() with duration_seconds = 0 — assert Err(VestingError::InvalidConfig)
• Verify no config is stored after any of these failed calls
• Verify a subsequent valid initialize() succeeds after the failed attempts

Labels: testing, forge-vesting

[Emins25]

Implemented and opened PR for this issue: #343

Summary:

• added regression coverage for total_amount = 0 and -1
• added regression coverage for duration_seconds = 0
• verified failed initialize attempts do not leave config behind before a valid initialize succeeds