Resource Leaks: Files not closed properly in multiple modules

Summary

Some Nettacker modules use open().read() without context managers, which can leave file handles open and cause resource leaks. This can lead to exhaustion of file descriptors in long‑running processes.

Problem

The following module contain unsafe file reads:

Resolution

Replace all bare open() calls with context managers:

# Before (unsafe)
content = open(filename).read()

# After (safe)
with open(filename) as f:
    content = f.read()

Testing

• Add new pytest tests under tests/lib/ to confirm:

• Files are read correctly.

• File handles are closed after reading.

• Edge cases (empty file, missing file) are handled properly.