add TimeRange.test_extend_to_encompass method

Author: Philip de Nier

mediatimestamp/immutable.py

@@ -1124,6 +1124,10 @@ def union_with_timerange(self, other):
         if not self.is_contiguous_with_timerange(other):
             raise ValueError("Timeranges {} and {} are not contiguous, so cannot take the union.".format(self, other))
 
+        return self.extend_to_encompass_timerange(other)
+
+    def extend_to_encompass_timerange(self, other):
+        """Returns the timerange that encompasses this and the other timerange."""
         if self.is_empty():
             return other
 

tests/test_immutable.py

@@ -1519,7 +1519,7 @@ def test_normalise(self):
                                  msg=("{!r}.normalise({}, {}, rounding={}) == {!r}, expected {!r}"
                                       .format(tr, rate.numerator, rate.denominator, rounding, result, expected)))
 
-    def test_union(self):
+    def test_extend_to_encompass(self):
         test_data = [
             (TimeRange.from_str("()"), TimeRange.from_str("()"),
              TimeRange.from_str("()")),
@@ -1545,15 +1545,35 @@ def test_union(self):
              TimeRange.from_str("[5:0_15:0)")),
             (TimeRange.from_str("()"), TimeRange.from_str("_15:0)"),
              TimeRange.from_str("_15:0)")),
+
+            # discontiguous
+            (TimeRange.from_str("_0:0)"), TimeRange.from_str("(0:0_"),
+             TimeRange.from_str("_")),
+            (TimeRange.from_str("(0:0_"), TimeRange.from_str("_0:0)"),
+             TimeRange.from_str("_")),
+            (TimeRange.from_str("[0:0_5:0)"), TimeRange.from_str("(5:0_15:0)"),
+             TimeRange.from_str("[0:0_15:0)")),
+            (TimeRange.from_str("(5:0_15:0)"), TimeRange.from_str("[0:0_5:0)"),
+             TimeRange.from_str("[0:0_15:0)")),
+            (TimeRange.from_str("[0:0_5:0)"), TimeRange.from_str("[10:0_15:0)"),
+             TimeRange.from_str("[0:0_15:0)")),
+            (TimeRange.from_str("[10:0_15:0)"), TimeRange.from_str("[0:0_5:0)"),
+             TimeRange.from_str("[0:0_15:0)")),
         ]
 
         for (first, second, expected) in test_data:
             with self.subTest(first=first, second=second, expected=expected):
-                self.assertEqual(first.union_with_timerange(second), expected)
+                self.assertEqual(first.extend_to_encompass_timerange(second), expected)
 
+    def test_union_raises(self):
+        # discontiguous part of test_extend_to_encompass raises for a union
         test_data = [
             (TimeRange.from_str("_0:0)"), TimeRange.from_str("(0:0_")),
+            (TimeRange.from_str("(0:0_"), TimeRange.from_str("_0:0)")),
+            (TimeRange.from_str("[0:0_5:0)"), TimeRange.from_str("(5:0_15:0)")),
+            (TimeRange.from_str("(5:0_15:0)"), TimeRange.from_str("[0:0_5:0)")),
             (TimeRange.from_str("[0:0_5:0)"), TimeRange.from_str("[10:0_15:0)")),
+            (TimeRange.from_str("[10:0_15:0)"), TimeRange.from_str("[0:0_5:0)")),
         ]
 
         for (first, second) in test_data: