--- a/tests/test_options/test_replay.py
+++ b/tests/test_options/test_replay.py
@@ -69,7 +69,7 @@ def test_replay_match_basename():
     create_file('xxx', 'test1/b')
     create_file('xxx', 'test2/a')
 
-    replay_path = '/tmp/replay.json'
+    replay_path = os.path.join(TESTDIR_NAME, 'replay.json')
 
     head, *data, footer = run_rmlint('-o json:{p}'.format(
         p=replay_path
@@ -104,7 +104,7 @@ def test_replay_hidden():
     create_file('xxx', 'test/.a')
     create_file('xxx', 'test/.b')
 
-    replay_path = '/tmp/replay.json'
+    replay_path = os.path.join(TESTDIR_NAME, 'replay.json')
 
     head, *data, footer = run_rmlint('--hidden -o json:{p}'.format(
         p=replay_path
@@ -130,7 +130,7 @@ def test_replay_must_match_tagged():
     create_file('xxx', 'test_a/a')
     create_file('xxx', 'test_b/a')
 
-    replay_path = '/tmp/replay.json'
+    replay_path = os.path.join(TESTDIR_NAME, 'replay.json')
 
     head, *data, footer = run_rmlint('-o json:{p}'.format(
         p=replay_path
@@ -182,7 +182,7 @@ def test_sorting():
             (''.join(p) for p in permutations(all_opts, n_terms))
         )
 
-    replay_path = '/tmp/replay.json'
+    replay_path = os.path.join(TESTDIR_NAME, 'replay.json')
 
     for combo in combos:
         combo_str = '-y ' + combo
@@ -218,7 +218,7 @@ def test_replay_no_dir():
 
     try:
         os.chdir(TESTDIR_NAME)
-        replay_path = '/tmp/replay.json'
+        replay_path = os.path.join(TESTDIR_NAME, 'replay.json')
         head, *data, footer = run_rmlint(
                 '-o json:{p}'.format(p=replay_path),
                 use_default_dir=False,
@@ -242,7 +242,7 @@ def test_replay_unicode_fuckup():
     create_file('xxx', names[1])
     create_file('xxx', names[2])
 
-    replay_path = '/tmp/replay.json'
+    replay_path = os.path.join(TESTDIR_NAME, 'replay.json')
 
     head, *data, footer = run_rmlint('-o json:{p}'.format(p=replay_path))
     assert len(data) == 3
@@ -260,8 +260,8 @@ def test_replay_tagged_order():
     create_file('xxx', 'b/1')
     create_file('xxx', 'b/2')
 
-    replay_path_a = '/tmp/replay-a.json'
-    replay_path_b = '/tmp/replay-b.json'
+    replay_path_a = os.path.join(TESTDIR_NAME, 'replay-a.json')
+    replay_path_b = os.path.join(TESTDIR_NAME, 'replay-b.json')
 
     # Create replay-a.json
     head, *data, footer = run_rmlint(
@@ -326,7 +326,7 @@ def test_replay_duplicate_directory_size():
     create_file('xxx', 'a/xxx')
     create_file('xxx', 'b/xxx')
 
-    replay_path = '/tmp/replay.json'
+    replay_path = os.path.join(TESTDIR_NAME, 'replay.json')
     head, *data, footer = run_rmlint('-o json:{p} -S a'.format(p=replay_path))
     assert len(data) == 2
 
@@ -427,7 +427,7 @@ def test_replay_pack_directories():
     create_pack_and_unpack_scenario()
 
     # Do a run without -D and pack it later during --replay.
-    replay_path = '/tmp/replay.json'
+    replay_path = os.path.join(TESTDIR_NAME, 'replay.json')
 
     head, *data, footer = run_rmlint('-o json:{p} -S ahD'.format(p=replay_path))
     assert len(data) == 13
@@ -449,7 +449,7 @@ def test_replay_unpack_directories():
     create_pack_and_unpack_scenario()
 
     # Do a run with -D and pack it later during --replay.
-    replay_path = '/tmp/replay.json'
+    replay_path = os.path.join(TESTDIR_NAME, 'replay.json')
     head, *data, footer = run_rmlint('-o json:{p} -S ahD -D'.format(p=replay_path))
 
     assert len(data) == 21
--- a/tests/test_options/test_size.py
+++ b/tests/test_options/test_size.py
@@ -90,7 +90,7 @@ def test_replay_size():
     create_file('yyy', 'b/yyy')
     create_testdir('empty_dir')
 
-    replay_path = '/tmp/replay.json'
+    replay_path = os.path.join(TESTDIR_NAME, 'replay.json')
     head, *data, footer = run_rmlint('-o json:{p}'.format(
         p=replay_path
     ))
--- a/tests/test_options/test_stdin.py
+++ b/tests/test_options/test_stdin.py
@@ -69,7 +69,6 @@ def test_path_starting_with_dash():
         os.chdir(TESTDIR_NAME)
         data = check_output(
             [cwd + '/rmlint', '-o', 'json', '-S', 'a', '--', subdir],
-            stderr=STDOUT
         )
     finally:
         os.chdir(cwd)
--- a/tests/utils.py
+++ b/tests/utils.py
@@ -133,7 +133,7 @@ def run_rmlint_once(*args,
 
     cmd += shlex.split(' '.join(args))
     if with_json:
-        cmd += ['-o', 'json:/tmp/out.json', '-c', 'json:oneline']
+        cmd += ['-o', 'json:' + os.path.join(TESTDIR_NAME, 'out.json'), '-c', 'json:oneline']
 
     for idx, output in enumerate(outputs or []):
         cmd.append('-o')
@@ -168,7 +168,7 @@ def run_rmlint_once(*args,
         return output
 
     if with_json:
-        with open('/tmp/out.json', 'r') as f:
+        with open(os.path.join(TESTDIR_NAME, 'out.json'), 'r') as f:
             json_data = json.loads(f.read())
     else:
         json_data = []