tests/docs: Add test for --consider-mtime

docs/rmlint.1.rst

@@ -468,6 +468,11 @@ Rarely used, miscellaneous options
     Also it might be useful for approximate comparison where it suffices when
     the file is the same in the middle part.
 
+:``-z --consider-mtime`` / ``-Z --ignore-mtime`` (**default**):
+
+    Only consider those files as duplicates that have the same content and
+    the same modification time (mtime).
+
 :``--with-fiemap`` (**default**) / ``--without-fiemap``:
 
     Enable or disable reading the file extents on rotational disk in order to

tests/test_options/test_consider_mtime.py

@@ -0,0 +1,35 @@
+#!/usr/bin/env python3
+# encoding: utf-8
+from nose import with_setup
+from tests.utils import *
+
+import os
+import subprocess
+
+
+@with_setup(usual_setup_func, usual_teardown_func)
+def test_consider_mtime():
+    create_file('xxx', 'a')
+    create_file('xxx', 'b')
+    create_file('xxx', 'c')
+
+    def set_mtime(path, mtime):
+        full_path = os.path.join(TESTDIR_NAME, path)
+        subprocess.call(['touch', '-m', '-d', str(mtime), full_path])
+
+    set_mtime('a', '2004-02-29  16:21:42')
+    set_mtime('b', '2004-02-29  16:21:42')
+    set_mtime('c', '2004-02-29  16:21:43')
+
+    head, *data, footer = run_rmlint('--ignore-mtime')
+    assert len(data) == 3
+    assert footer['total_files'] == 3
+    assert footer['total_lint_size'] == 6
+    assert footer['duplicates'] == 2
+
+    head, *data, footer = run_rmlint('--consider-mtime')
+
+    assert len(data) == 2
+    assert footer['total_files'] == 3
+    assert footer['total_lint_size'] == 3
+    assert footer['duplicates'] == 1