cras_py_common: string_utils: Fixed bug stringifying negative durations.

Author: peci1

cras_py_common/src/cras/string_utils.py

@@ -41,7 +41,9 @@ def __time_val_to_str(time):
     :return: The string representation.
     :rtype: str
     """
-    return "%i.%09i" % (time.secs, time.nsecs)
+    # We can't directly print .secs, .nsecs, as that would fail for negative durations
+    nsecs = time.to_nsec()
+    return "%i.%09i" % (nsecs // 1000000000, nsecs % 1000000000)
 
 
 __to_str_functions = {

cras_py_common/test/test_string_utils.py

@@ -51,8 +51,10 @@ def test_to_str(self):
         self.assertEqual("1.000000001", to_str(Duration(1, 1)))
         self.assertEqual("1.100000000", to_str(Duration(1, 100000000)))
         self.assertEqual("-1.000000000", to_str(-Duration(1)))
-        self.assertEqual("-1.000000001", to_str(Duration(-1, 1)))
-        self.assertEqual("-1.100000000", to_str(Duration(-1, 100000000)))
+        # negative durations mean "10e9 * secs + nsecs", so (-1, 1) is actually
+        # (-1 * 10e9 + 1) = -999999999
+        self.assertEqual("-0.999999999", to_str(Duration(-1, 1)))
+        self.assertEqual("-0.9", to_str(Duration(-1, 100000000)))
         self.assertEqual("1.000000000", to_str(Time(1)))
         self.assertEqual("1.000000001", to_str(Time(1, 1)))
         self.assertEqual("1.100000000", to_str(Time(1, 100000000)))