acronym: update tests to 1.7.0 (exercism#1649)

Add underscore emphasis test.

Author: AnAccountForReportingBugs

exercises/acronym/acronym_test.py

@@ -3,7 +3,7 @@
 from acronym import abbreviate
 
 
-# Tests adapted from `problem-specifications//canonical-data.json` @ v1.6.0
+# Tests adapted from `problem-specifications//canonical-data.json` @ v1.7.0
 
 class AcronymTest(unittest.TestCase):
     def test_basic(self):
@@ -34,6 +34,9 @@ def test_consecutive_delimiters(self):
     def test_apostrophes(self):
         self.assertEqual(abbreviate("Halley's Comet"), 'HC')
 
+    def test_underscore_emphasis(self):
+        self.assertEqual(abbreviate("The Road _Not_ Taken"), 'TRNT')
+
 
 if __name__ == '__main__':
     unittest.main()