From 6f970a41e521523ccc39f29a175751fef41138fb Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Sybren=20A=2E=20St=C3=BCvel?= <sybren@stuvel.eu>
Date: Tue, 11 Oct 2016 10:52:27 +0200
Subject: [PATCH] Added utils.find_in_path + unittest

---
 blender_cloud/utils.py                        | 33 +++++++++++++++++++
 requirements-dev.txt                          |  8 +++++
 .../dir_a1/dir_a2/dir_a3/find_me.txt          |  0
 .../dir_b1/dir_b2/find_me.txt                 |  0
 tests/test_utils.py                           | 25 ++++++++++++++
 5 files changed, 66 insertions(+)
 create mode 100644 requirements-dev.txt
 create mode 100644 tests/test_really_breadth_first/dir_a1/dir_a2/dir_a3/find_me.txt
 create mode 100644 tests/test_really_breadth_first/dir_b1/dir_b2/find_me.txt
 create mode 100644 tests/test_utils.py

diff --git a/blender_cloud/utils.py b/blender_cloud/utils.py
index 635b25e..5512a3a 100644
--- a/blender_cloud/utils.py
+++ b/blender_cloud/utils.py
@@ -16,6 +16,8 @@
 #
 # ##### END GPL LICENSE BLOCK #####
 
+import pathlib
+
 
 def sizeof_fmt(num: int, suffix='B') -> str:
     """Returns a human-readable size.
@@ -29,3 +31,34 @@ def sizeof_fmt(num: int, suffix='B') -> str:
         num /= 1024
 
     return '%.1f Yi%s' % (num, suffix)
+
+
+def find_in_path(path: pathlib.Path, filename: str) -> pathlib.Path:
+    """Performs a breadth-first search for the filename.
+
+    Returns the path that contains the file, or None if not found.
+    """
+
+    import collections
+
+    # Be lenient on our input type.
+    if isinstance(path, str):
+        path = pathlib.Path(path)
+
+    if not path.exists():
+        return None
+    assert path.is_dir()
+
+    to_visit = collections.deque([path])
+    while to_visit:
+        this_path = to_visit.popleft()
+
+        for subpath in this_path.iterdir():
+            if subpath.is_dir():
+                to_visit.append(subpath)
+                continue
+
+            if subpath.name == filename:
+                return subpath
+
+    return None
diff --git a/requirements-dev.txt b/requirements-dev.txt
new file mode 100644
index 0000000..f9c090a
--- /dev/null
+++ b/requirements-dev.txt
@@ -0,0 +1,8 @@
+-r requirements.txt
+
+# Primary requirements
+pytest==3.0.3
+
+# Secondary requirements
+py==1.4.31
+
diff --git a/tests/test_really_breadth_first/dir_a1/dir_a2/dir_a3/find_me.txt b/tests/test_really_breadth_first/dir_a1/dir_a2/dir_a3/find_me.txt
new file mode 100644
index 0000000..e69de29
diff --git a/tests/test_really_breadth_first/dir_b1/dir_b2/find_me.txt b/tests/test_really_breadth_first/dir_b1/dir_b2/find_me.txt
new file mode 100644
index 0000000..e69de29
diff --git a/tests/test_utils.py b/tests/test_utils.py
new file mode 100644
index 0000000..865aa69
--- /dev/null
+++ b/tests/test_utils.py
@@ -0,0 +1,25 @@
+"""Unittests for blender_cloud.utils."""
+
+import pathlib
+import unittest
+
+from blender_cloud import utils
+
+
+class FindInPathTest(unittest.TestCase):
+    def test_nonexistant_path(self):
+        path = pathlib.Path('/doesnotexistreally')
+        self.assertFalse(path.exists())
+        self.assertIsNone(utils.find_in_path(path, 'jemoeder.blend'))
+
+    def test_really_breadth_first(self):
+        """A depth-first test might find dir_a1/dir_a2/dir_a3/find_me.txt first."""
+
+        path = pathlib.Path(__file__).parent / 'test_really_breadth_first'
+        found = utils.find_in_path(path, 'find_me.txt')
+        self.assertEqual(path / 'dir_b1' / 'dir_b2' / 'find_me.txt', found)
+
+    def test_nonexistant_file(self):
+        path = pathlib.Path(__file__).parent / 'test_really_breadth_first'
+        found = utils.find_in_path(path, 'do_not_find_me.txt')
+        self.assertEqual(None, found)