Update tests

Update README with new installation methods

.github/workflows/lint-and-security.yml

@@ -1,7 +1,7 @@
-name: CI
+name: Lint & Security
 
 on:
-  push:
+  pull_request:
 
 jobs:
   precommit-and-security:

README.md

@@ -128,25 +128,49 @@ Invalid or non-numeric values fall back to 30 days.
 
 **Note:** _a value of 0 is **invalid**_.
 
+### Built-in diff
+This shows a _git-like_ diff of the current file version and any of that file backups.
+```
+mirro --diff file file.orig.20251121T163121
+```
 
 ## Installation
 
+### From package manager
+
+This is the preferred method of installation.
+
+**Ubuntu 22.04 and 24.04**
+```
+sudo add-apt-repository ppa:mdaleo/mirro
+sudo apt update
+sudo apt install mirro
+```
+
+**Fedora 41, 42, 43**
+```
+sudo dnf copr enable mdaleo/mirro
+sudo dnf install resrm
+```
+
+### From PyPI
+
 **NOTE:** To use `mirro` with `sudo`, the path to `mirro` must be in the `$PATH` seen by `root`.\
 Either:
 
- * install `mirro` as `root` (_preferred_), or
+ * install `mirro` as `root`, or
  * add the path to `mirro` to the `secure_path` parameter in `/etc/sudoers`. For example, where `/home/user/.local/bin` is where `mirro` is:
 
 ``` bash
 Defaults secure_path="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/home/user/.local/bin"
 ```
 
-Install via PyPI (preferred):
+Install with:
 ```
 pip install mirro
 ```
 
-Or clone the repo and install locally:
+### From this repository
 ```
 git clone https://github.com/mdaleo404/mirro.git
 cd mirro/

pyproject.toml

@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "mirro"
-version = "0.3.0"
+version = "0.4.0"
 description = "A safe editing wrapper: edits a temp copy, compares, and saves original backup if changed."
 authors = ["Marco D'Aleo <marco@marcodaleo.com>"]
 license = "GPL-3.0-or-later"

src/mirro/main.py

@@ -4,6 +4,7 @@ import tempfile
 import subprocess
 import os
 import textwrap
+import difflib
 from pathlib import Path
 import time
 
@@ -49,6 +50,31 @@ def backup_original(
     return backup_path
 
 
+def strip_mirro_header(text: str) -> str:
+    """
+    Strip only mirro's backup header (if present).
+    Never removes shebangs or anything else.
+    """
+    lines = text.splitlines(keepends=True)
+
+    # If there's no mirro header, return the text unchanged
+    if not lines or not lines[0].startswith(
+        "# ---------------------------------------------------"
+    ):
+        return text
+
+    # Otherwise skip all header lines until the first blank line
+    i = 0
+    while i < len(lines):
+        if lines[i].strip() == "":
+            i += 1  # skip the blank separator line
+            break
+        i += 1
+
+    # 'i' now points to the first real line of the original file
+    return "".join(lines[i:])
+
+
 def main():
     parser = argparse.ArgumentParser(
         description="Safely edit a file with automatic original backup if changed."
@@ -87,9 +113,85 @@ def main():
         help="Prune backups older than MIRRO_BACKUPS_LIFE days, or 'all' to delete all backups",
     )
 
+    parser.add_argument(
+        "--diff",
+        nargs=2,
+        metavar=("FILE", "BACKUP"),
+        help="Show a unified diff between FILE and BACKUP and exit",
+    )
+
     # Parse only options. Leave everything else untouched.
     args, positional = parser.parse_known_args()
 
+    if args.diff:
+        file_arg, backup_arg = args.diff
+
+        file_path = Path(file_arg).expanduser().resolve()
+
+        # Resolve backup: if it’s not absolute or ~, treat it as a filename in the backup dir
+        if os.path.isabs(backup_arg) or backup_arg.startswith("~"):
+            backup_path = Path(backup_arg).expanduser().resolve()
+        else:
+            backup_dir = Path(args.backup_dir).expanduser().resolve()
+            backup_path = backup_dir / backup_arg
+
+        if not file_path.exists():
+            print(f"File not found: {file_path}")
+            return 1
+        if not backup_path.exists():
+            print(f"Backup not found: {backup_path}")
+            return 1
+
+        # Enforce same base filename while diffing
+        target_name = file_path.name
+        backup_name = backup_path.name
+
+        if not backup_name.startswith(target_name + ".orig."):
+            print(
+                f"Error: Backup '{backup_name}' does not match the file being diffed.\n"
+                f"Expected backup file starting with: {target_name}.orig."
+            )
+            return 1
+
+        original = file_path.read_text(
+            encoding="utf-8", errors="replace"
+        ).splitlines()
+        backup_raw = backup_path.read_text(encoding="utf-8", errors="replace")
+
+        backup_stripped = strip_mirro_header(backup_raw)
+        backup = backup_stripped.splitlines()
+
+        # Generate a clean diff (no trailing line noise)
+        diff = difflib.unified_diff(
+            backup,
+            original,
+            fromfile=f"a/{file_path.name}",
+            tofile=f"b/{file_path.name}",
+            lineterm="",
+        )
+
+        # Colors
+        RED = "\033[31m"
+        GREEN = "\033[32m"
+        CYAN = "\033[36m"
+        RESET = "\033[0m"
+
+        for line in diff:
+            if (
+                line.startswith("---")
+                or line.startswith("+++")
+                or line.startswith("@@")
+            ):
+                print(f"{CYAN}{line}{RESET}")
+            elif line.startswith("+"):
+                print(f"{GREEN}{line}{RESET}")
+            elif line.startswith("-"):
+                print(f"{RED}{line}{RESET}")
+            else:
+                print(line)
+
+        return
+
     if args.list:
         import pwd, grp
 
@@ -171,26 +273,7 @@ def main():
 
         # read and strip header
         raw = last.read_text(encoding="utf-8", errors="replace")
-        restored = []
-        skipping = True
-        for line in raw.splitlines(keepends=True):
-            # header ends at first blank line after the dashed line block
-            if skipping:
-                if line.strip() == "" and restored == []:
-                    # allow only after header
-                    continue
-                if line.startswith("#") or line.strip() == "":
-                    continue
-                skipping = False
-            restored.append(line)
-
-        # if header wasn't present, restored = raw
-        if not restored:
-            restored_text = raw
-        else:
-            restored_text = "".join(restored)
-
-        # write the restored file back
+        restored_text = strip_mirro_header(raw)
         target.write_text(restored_text, encoding="utf-8")
 
         print(f"Restored {target} from backup {last.name}")

tests/test_mirro.py

@@ -48,17 +48,49 @@ def test_write_file(tmp_path):
     assert p.read_text(encoding="utf-8") == "data"
 
 
+# ============================================================
+# strip_mirro_header
+# ============================================================
+
+
+def test_strip_header_removes_header():
+    header_text = (
+        "# ---------------------------------------------------\n"
+        "# mirro backup\n"
+        "# something\n"
+        "# ---------------------------------------------------\n"
+        "\n"
+        "#!/bin/bash\n"
+        "echo hi\n"
+    )
+
+    out = mirro.strip_mirro_header(header_text)
+    assert out.startswith("#!/bin/bash")
+    assert "mirro backup" not in out
+
+
+def test_strip_header_preserves_shebang():
+    text = "#!/usr/bin/env python3\nprint('hi')\n"
+    out = mirro.strip_mirro_header(text)
+    assert out == text  # unchanged
+
+
+def test_strip_header_non_header_file():
+    text = "# just a comment\nvalue\n"
+    out = mirro.strip_mirro_header(text)
+    assert out == text
+
+
 # ============================================================
 # backup_original
 # ============================================================
 
 
 def test_backup_original(tmp_path, monkeypatch):
-    original_path = tmp_path / "test.txt"
+    original_path = tmp_path / "a.txt"
     original_content = "ABC"
     backup_dir = tmp_path / "backups"
 
-    # Freeze timestamps
     monkeypatch.setattr(
         time,
         "gmtime",
@@ -78,14 +110,14 @@ def test_backup_original(tmp_path, monkeypatch):
     )
 
     assert backup_path.exists()
-    text = backup_path.read_text(encoding="utf-8")
+    text = backup_path.read_text()
     assert "mirro backup" in text
-    assert "Original file:" in text
-    assert original_content in text
+    assert "Original file" in text
+    assert "ABC" in text
 
 
 # ============================================================
-# Helper to run main()
+# Helper to simulate main()
 # ============================================================
 
 
@@ -100,11 +132,8 @@ def simulate_main(
     file_exists=True,
     override_access=None,
 ):
-    """Utility to simulate mirro.main()"""
-
     monkeypatch.setenv("EDITOR", editor)
 
-    # Fake editor
     def fake_call(cmd):
         temp = Path(cmd[-1])
         if edited_content is None:
@@ -115,13 +144,11 @@ def simulate_main(
 
     monkeypatch.setattr(subprocess, "call", fake_call)
 
-    # Access override if provided
     if override_access:
         monkeypatch.setattr(os, "access", override_access)
     else:
         monkeypatch.setattr(os, "access", lambda p, m: True)
 
-    # Set up file as needed
     target = Path(args[-1]).expanduser().resolve()
     if file_exists:
         target.parent.mkdir(parents=True, exist_ok=True)
@@ -135,7 +162,7 @@ def simulate_main(
 
 
 # ============================================================
-# main: missing file argument
+# main: missing positional file
 # ============================================================
 
 
@@ -143,24 +170,23 @@ def test_main_missing_argument(capsys):
     with patch("sys.argv", ["mirro"]):
         with pytest.raises(SystemExit):
             mirro.main()
-
     assert (
         "the following arguments are required: file" in capsys.readouterr().err
     )
 
 
 # ============================================================
-# main: unchanged file (line 137)
+# main: unchanged file
 # ============================================================
 
 
 def test_main_existing_unchanged(tmp_path, monkeypatch, capsys):
     target = tmp_path / "file.txt"
-    target.write_text("hello\n", encoding="utf-8")
+    target.write_text("hello\n")
 
     def fake_call(cmd):
         temp = Path(cmd[-1])
-        temp.write_text("hello\n", encoding="utf-8")
+        temp.write_text("hello\n")
 
     monkeypatch.setenv("EDITOR", "nano")
     monkeypatch.setattr(subprocess, "call", fake_call)
@@ -169,8 +195,7 @@ def test_main_existing_unchanged(tmp_path, monkeypatch, capsys):
     with patch("sys.argv", ["mirro", str(target)]):
         mirro.main()
 
-    out = capsys.readouterr().out
-    assert "file hasn't changed" in out
+    assert "file hasn't changed" in capsys.readouterr().out
 
 
 # ============================================================
@@ -179,7 +204,7 @@ def test_main_existing_unchanged(tmp_path, monkeypatch, capsys):
 
 
 def test_main_existing_changed(tmp_path, monkeypatch, capsys):
-    target = tmp_path / "file2.txt"
+    target = tmp_path / "f2.txt"
 
     result, out = simulate_main(
         monkeypatch,
@@ -191,7 +216,7 @@ def test_main_existing_changed(tmp_path, monkeypatch, capsys):
     )
 
     assert "file changed; original backed up at" in out
-    assert target.read_text(encoding="utf-8") == "new\n"
+    assert target.read_text() == "new\n"
 
 
 # ============================================================
@@ -233,68 +258,57 @@ def test_main_new_file_changed(tmp_path, monkeypatch, capsys):
     )
 
     assert "file changed; original backed up at" in out
-    assert new.read_text(encoding="utf-8") == "XYZ\n"
+    assert new.read_text() == "XYZ\n"
 
 
 # ============================================================
-# main: permission denied for existing file (line 78)
+# Permission denied branches
 # ============================================================
 
 
 def test_main_permission_denied_existing(tmp_path, monkeypatch, capsys):
-    target = tmp_path / "blocked.txt"
-    target.write_text("hello", encoding="utf-8")
+    tgt = tmp_path / "blocked.txt"
+    tgt.write_text("hi")
 
     monkeypatch.setenv("EDITOR", "nano")
     monkeypatch.setattr(os, "access", lambda p, m: False)
 
-    with patch("sys.argv", ["mirro", str(target)]):
+    with patch("sys.argv", ["mirro", str(tgt)]):
         result = mirro.main()
 
-    out = capsys.readouterr().out
-    assert "Need elevated privileges to open" in out
     assert result == 1
-
-
-# ============================================================
-# main: permission denied creating file (line 84)
-# ============================================================
+    assert "Need elevated privileges to open" in capsys.readouterr().out
 
 
 def test_main_permission_denied_create(tmp_path, monkeypatch, capsys):
-    newfile = tmp_path / "subdir" / "nofile.txt"
-    parent = newfile.parent
-    parent.mkdir(parents=True, exist_ok=True)
+    new = tmp_path / "sub/xx.txt"
+    new.parent.mkdir(parents=True)
 
-    # Directory is not writable
     def fake_access(path, mode):
-        if path == parent:
-            return False
-        return True
+        return False if path == new.parent else True
 
     monkeypatch.setattr(os, "access", fake_access)
     monkeypatch.setenv("EDITOR", "nano")
 
-    with patch("sys.argv", ["mirro", str(newfile)]):
+    with patch("sys.argv", ["mirro", str(new)]):
         result = mirro.main()
 
-    out = capsys.readouterr().out
-    assert "Need elevated privileges to create" in out
     assert result == 1
+    assert "Need elevated privileges to create" in capsys.readouterr().out
 
 
 # ============================================================
-# main: non-nano editor (ordering branch)
+# Editor ordering: non-nano branch
 # ============================================================
 
 
 def test_main_editor_non_nano(tmp_path, monkeypatch, capsys):
     target = tmp_path / "vim.txt"
-    target.write_text("old\n", encoding="utf-8")
+    target.write_text("old\n")
 
     def fake_call(cmd):
-        temp = Path(cmd[1])  # in non-nano mode
-        temp.write_text("edited\n", encoding="utf-8")
+        temp = Path(cmd[1])
+        temp.write_text("edited\n")
 
     monkeypatch.setenv("EDITOR", "vim")
     monkeypatch.setattr(subprocess, "call", fake_call)
@@ -303,4 +317,251 @@ def test_main_editor_non_nano(tmp_path, monkeypatch, capsys):
     with patch("sys.argv", ["mirro", str(target)]):
         mirro.main()
 
-    assert target.read_text(encoding="utf-8") == "edited\n"
+    assert target.read_text() == "edited\n"
+
+
+# ============================================================
+# --list
+# ============================================================
+
+
+def test_main_list_no_dir(tmp_path, capsys):
+    with patch(
+        "sys.argv", ["mirro", "--list", "--backup-dir", str(tmp_path / "none")]
+    ):
+        mirro.main()
+    assert "No backups found." in capsys.readouterr().out
+
+
+def test_main_list_entries(tmp_path, capsys):
+    d = tmp_path / "bk"
+    d.mkdir()
+    (d / "a.txt.orig.1").write_text("x")
+    (d / "b.txt.orig.2").write_text("y")
+
+    with patch("sys.argv", ["mirro", "--list", "--backup-dir", str(d)]):
+        mirro.main()
+
+    out = capsys.readouterr().out
+    assert "a.txt.orig.1" in out
+    assert "b.txt.orig.2" in out
+
+
+# ============================================================
+# --restore-last
+# ============================================================
+
+
+def test_restore_last_no_dir(tmp_path, capsys):
+    d = tmp_path / "none"
+    target = tmp_path / "x.txt"
+    with patch(
+        "sys.argv",
+        ["mirro", "--restore-last", str(target), "--backup-dir", str(d)],
+    ):
+        result = mirro.main()
+
+    assert result == 1
+    assert "No backup directory found." in capsys.readouterr().out
+
+
+def test_restore_last_no_backups(tmp_path, capsys):
+    d = tmp_path / "bk"
+    d.mkdir()
+    target = tmp_path / "t.txt"
+
+    with patch(
+        "sys.argv",
+        ["mirro", "--restore-last", str(target), "--backup-dir", str(d)],
+    ):
+        result = mirro.main()
+
+    assert result == 1
+    assert "No backups found" in capsys.readouterr().out
+
+
+def test_restore_last_success(tmp_path, capsys):
+    d = tmp_path / "bk"
+    d.mkdir()
+    target = tmp_path / "t.txt"
+
+    mirro_header = (
+        "# ---------------------------------------------------\n"
+        "# mirro backup\n"
+        "# Original file: x\n"
+        "# Timestamp: test\n"
+        "# Delete this header if you want to restore the file\n"
+        "# ---------------------------------------------------\n"
+        "\n"
+    )
+
+    b1 = d / "t.txt.orig.2020"
+    b2 = d / "t.txt.orig.2021"
+
+    b1.write_text(mirro_header + "old1")
+    b2.write_text(mirro_header + "old2")
+
+    # ensure newest
+    os.utime(b2, (time.time(), time.time()))
+
+    with patch(
+        "sys.argv",
+        ["mirro", "--restore-last", str(target), "--backup-dir", str(d)],
+    ):
+        mirro.main()
+
+    assert target.read_text() == "old2"
+    assert "Restored" in capsys.readouterr().out
+
+
+# ============================================================
+# --prune-backups
+# ============================================================
+
+
+def test_prune_all(tmp_path, capsys):
+    d = tmp_path / "bk"
+    d.mkdir()
+    (d / "a").write_text("x")
+    (d / "b").write_text("y")
+
+    with patch(
+        "sys.argv", ["mirro", "--prune-backups=all", "--backup-dir", str(d)]
+    ):
+        mirro.main()
+
+    out = capsys.readouterr().out
+    assert "Removed ALL backups" in out
+    assert not any(d.iterdir())
+
+
+def test_prune_numeric(tmp_path, capsys):
+    d = tmp_path / "bk"
+    d.mkdir()
+
+    old = d / "old"
+    new = d / "new"
+    old.write_text("x")
+    new.write_text("y")
+
+    one_day_seconds = 86400
+
+    os.utime(
+        old,
+        (
+            time.time() - one_day_seconds * 10,
+            time.time() - one_day_seconds * 10,
+        ),
+    )
+    os.utime(new, None)
+
+    with patch(
+        "sys.argv", ["mirro", "--prune-backups=5", "--backup-dir", str(d)]
+    ):
+        mirro.main()
+
+    out = capsys.readouterr().out
+    assert "Removed 1" in out
+    assert new.exists()
+    assert not old.exists()
+
+
+def test_prune_default_env(tmp_path, monkeypatch, capsys):
+    monkeypatch.setenv("MIRRO_BACKUPS_LIFE", "1")
+
+    d = tmp_path / "bk"
+    d.mkdir()
+
+    f = d / "x"
+    f.write_text("hi")
+
+    os.utime(f, (time.time() - 86400 * 2, time.time() - 86400 * 2))
+
+    with patch(
+        "sys.argv", ["mirro", "--prune-backups", "--backup-dir", str(d)]
+    ):
+        mirro.main()
+
+    assert "Removed 1" in capsys.readouterr().out
+
+
+def test_prune_invalid_env(tmp_path, monkeypatch, capsys):
+    monkeypatch.setenv("MIRRO_BACKUPS_LIFE", "nope")
+
+    d = tmp_path / "bk"
+    d.mkdir()
+
+    with patch(
+        "sys.argv", ["mirro", "--prune-backups", "--backup-dir", str(d)]
+    ):
+        mirro.main()
+
+    out = capsys.readouterr().out
+    assert "Invalid MIRRO_BACKUPS_LIFE value" in out
+
+
+def test_prune_invalid_arg(tmp_path, capsys):
+    with patch("sys.argv", ["mirro", "--prune-backups=zzz"]):
+        result = mirro.main()
+
+    assert result == 1
+    assert "Invalid value for --prune-backups" in capsys.readouterr().out
+
+
+# ============================================================
+# --diff tests
+# ============================================================
+
+
+def test_diff_basic(tmp_path, capsys):
+    d = tmp_path / "bk"
+    d.mkdir()
+
+    file = tmp_path / "t.txt"
+    file.write_text("line1\nline2\n")
+
+    backup = d / "t.txt.orig.20250101T010203"
+    backup.write_text(
+        "# ---------------------------------------------------\n"
+        "# mirro backup\n"
+        "# whatever\n"
+        "\n"
+        "line1\nold\n"
+    )
+
+    with patch(
+        "sys.argv",
+        ["mirro", "--diff", str(file), backup.name, "--backup-dir", str(d)],
+    ):
+        mirro.main()
+
+    out = capsys.readouterr().out
+
+    assert "--- a/t.txt" in out
+    assert "+++ b/t.txt" in out
+    assert "@@" in out
+    assert "-old" in out
+    assert "+line2" in out
+
+
+def test_diff_wrong_backup_name_rejected(tmp_path, capsys):
+    d = tmp_path / "bk"
+    d.mkdir()
+
+    file = tmp_path / "foo.txt"
+    file.write_text("hello\n")
+
+    bad = d / "bar.txt.orig.20250101T010203"
+    bad.write_text("stuff\n")
+
+    with patch(
+        "sys.argv",
+        ["mirro", "--diff", str(file), bad.name, "--backup-dir", str(d)],
+    ):
+        result = mirro.main()
+
+    out = capsys.readouterr().out
+
+    assert result == 1
+    assert "does not match the file being diffed" in out
+    assert "foo.txt.orig." in out