feat: add suite of tests for utils module

This covers:
 - Source
 - SourceMedia
 - Interval

test/test_utils.py

@@ -0,0 +1,173 @@
+"""Test cases for utils"""
+import unittest
+
+import pipeline.utils as utils
+
+
+class TestSource(unittest.TestCase):
+    """Source is a container for source, path, and provider of a media file
+
+    source -- the source of the media file (eg, a URL or a local path)
+    path -- the path to the media file
+    provider -- the provider of the media file (eg, "FileInputJSON")
+
+    Accessing the object should return the path to the media file.
+
+    Methods:
+
+    duration() -- return the duration of the media file (uses ffprobe, result is cached)
+    """
+    # Happy path tests
+    def setUp(self):
+        self.source = "audio_clips/testclip-5min.aac"
+        self.path = "audio_clips/testclip-5min.aac"
+        self.provider = "FileInputJSON"
+        self._duration = 306.121214 # duration of testclip-5min.aac
+
+    def test_init(self):
+        source = utils.Source(self.source, self.path, self.provider)
+        self.assertEqual(source.source, self.source)
+        self.assertEqual(source.path, self.path)
+        self.assertEqual(source.provider, self.provider)
+
+    def test_str(self):
+        """Accessing the object should return the path to the media file"""
+        source = utils.Source(self.source, self.path, self.provider)
+        self.assertEqual(str(source), self.path)
+
+    def test_repr(self):
+        source = utils.Source(self.source, self.path, self.provider)
+        self.assertEqual(repr(source), f"Source({self.source}, {self.path}, {self.provider})")
+
+    def test_duration(self):
+        """Use a mock duration of 306.121214 for the test clip"""
+        source = utils.Source(self.source, self.path, self.provider)
+        self.assertEqual(source.duration(), self._duration)
+
+    # Sad path tests
+    def test_init_no_source(self):
+        with self.assertRaises(ValueError):
+            utils.Source("", self.path, self.provider)
+
+    def test_init_no_path(self):
+        with self.assertRaises(ValueError):
+            utils.Source(self.source, "", self.provider)
+
+    def test_init_no_provider(self):
+        with self.assertRaises(ValueError):
+            utils.Source(self.source, self.path, "")
+
+    def test_duration_no_file(self):
+        """Test that duration raises FileNotFoundError if the file does not exist"""
+        source = utils.Source(self.source, "fakepath-noexist!😇", self.provider)
+        # if that file actually exists I'll eat my hat
+        with self.assertRaises(FileNotFoundError):
+            source.duration()
+
+
+class TestSourceMedia(unittest.TestCase):
+    """SourceMedia is a container for Source objects"""
+    class FakeSource():
+        """Fake source object for testing SourceMedia
+
+         Since SourceMedia doesn't actually access any of the attributes of Source objects,
+         we can use a very empty class for testing.
+         """
+
+    def setUp(self):
+        self.source1 = self.FakeSource()
+        self.source2 = self.FakeSource()
+        self.source3 = self.FakeSource()
+        self.sources = [self.source1, self.source2, self.source3]
+
+    def test_init(self):
+        source_media = utils.SourceMedia(sources=self.sources)
+        self.assertEqual(source_media.sources, self.sources)
+
+    def test_iter(self):
+        source_media = utils.SourceMedia(sources=self.sources)
+        self.assertEqual(list(source_media), self.sources)
+
+
+class TestInterval(unittest.TestCase):
+    """Interval is a container for start, end and duration attributes"""
+    def setUp(self):
+        self.start = 0
+        self.end = 10
+        self.duration = 10
+
+    # Happy path tests
+
+    def test_init_start_end(self):
+        """Create an Interval using start and end attributes"""
+        interval = utils.Interval(start=self.start, end=self.end)
+        self.assertEqual(interval.start, self.start)
+        self.assertEqual(interval.end, self.end)
+        self.assertEqual(interval.duration, self.duration)
+
+    def test_init_start_duration(self):
+        """Create an Interval using start and duration attributes"""
+        interval = utils.Interval(start=self.start, duration=self.duration)
+        self.assertEqual(interval.start, self.start)
+        self.assertEqual(interval.end, self.end)
+        self.assertEqual(interval.duration, self.duration)
+
+    def test_init_end_duration(self):
+        """Create an Interval using end and duration attributes"""
+        interval = utils.Interval(end=self.end, duration=self.duration)
+        self.assertEqual(interval.start, self.start)
+        self.assertEqual(interval.end, self.end)
+        self.assertEqual(interval.duration, self.duration)
+
+    def test_from_start_classmethod(self):
+        """Create an Interval using the from_start classmethod (ie start attribute only- uses default duration)"""
+        interval = utils.Interval.from_start(start=self.start)
+        self.assertEqual(interval.start, self.start)
+        self.assertEqual(interval.end, interval.start + utils.Interval.DEFAULT_DURATION)
+        self.assertEqual(interval.duration, utils.Interval.DEFAULT_DURATION)
+
+    def test_from_end_classmethod(self):
+        """Create an Interval using the from_end classmethod (ie end attribute only- uses default duration)"""
+        interval = utils.Interval.from_end(end=self.end)
+        self.assertEqual(interval.start, interval.end - utils.Interval.DEFAULT_DURATION)
+        self.assertEqual(interval.end, self.end)
+        self.assertEqual(interval.duration, utils.Interval.DEFAULT_DURATION)
+
+    def test_repr(self):
+        interval = utils.Interval(start=self.start, end=self.end)
+        self.assertEqual(repr(interval), f"Interval({self.start}, {self.end}, {self.duration})")
+
+    def test_lt(self):
+        """Test the __lt__ method used for sorting Interval objects based on start time
+
+        If the start times are equal, the interval with the smaller end time is considered smaller
+        """
+        interval1 = utils.Interval(start=0, end=10)
+        interval2 = utils.Interval(start=0, end=15)
+        interval3 = utils.Interval(start=5, end=10)
+        interval4 = utils.Interval(start=5, end=15)
+        self.assertTrue(interval1 < interval2) # same start, interval1 has smaller end
+        self.assertTrue(interval1 < interval3) # interval1 start is smaller
+        self.assertTrue(interval3 > interval2) # interval3 start is larger
+        self.assertTrue(interval3 < interval4) # same start, interval3 has smaller end
+
+    def test_move_start(self):
+        """Test the move_start method - changes start time to time specified, keeps end time constant"""
+        interval = utils.Interval(start=self.start, end=self.end)
+        interval.move_start(5)
+        self.assertEqual(interval.start, 5)
+        self.assertEqual(interval.end, 10)
+        self.assertEqual(interval.duration, 5)
+
+    def test_move_start_relative(self):
+        """Test the move_start method with relative=True - changes start time by a relative amount"""
+        interval = utils.Interval(start=self.start, end=self.end)
+        interval.move_start(2, relative=True)
+        self.assertEqual(interval.start, 2)
+        self.assertEqual(interval.end, 10)
+        self.assertEqual(interval.duration, 8)
+
+
+
+if __name__ == "__main__":
+    unittest.main()