Add ns and us support to robot time string (#4491)

Time string now supports microsecond and nanosecond inputs like `1us`.

Co-authored-by: Mikko Kujala <mikko.kujala@fi.abb.com>

atest/testdata/standard_libraries/datetime/convert_time_input_format.robot

@@ -15,18 +15,22 @@ Time string           10 s                                  10
                       0 s                                   0
                       0.1 millisecond                       0.0001
                       0.123456789 ms                        0.000123456789
+                      123 μs                                0.000123
+                      1 ns                                  1E-9
 
 Number as string      10                                    10
                       0.5                                   0.5
                       -1                                    -1
                       0                                     0
                       0.123456789                           0.123456789
+                      1E-9                                  1E-9
 
 Number                ${42}                                 42
                       ${3.14}                               3.14
                       ${-0.5}                               -0.5
                       ${0}                                  0
                       ${0.123456789}                        0.123456789
+                      ${1E-9}                               1E-9
 
 Timer                 00:00:00.000                          0
                       00:00:00.001                          0.001

src/robot/libraries/DateTime.py

@@ -186,6 +186,8 @@
 - ``minutes``, ``minute``, ``mins``, ``min``, ``m``
 - ``seconds``, ``second``, ``secs``, ``sec``, ``s``
 - ``milliseconds``, ``millisecond``, ``millis``, ``ms``
+- ``microseconds``, ``microsecond``, ``us``, ``μs``
+- ``nanoseconds``, ``nanosecond``, ``ns``
 
 When returning a time string, it is possible to select between ``verbose``
 and ``compact`` representations using ``result_format`` argument. The verbose

src/robot/utils/robottime.py

@@ -78,7 +78,7 @@ def _time_string_to_secs(timestr):
     timestr = _normalize_timestr(timestr)
     if not timestr:
         return None
-    millis = secs = mins = hours = days = 0
+    nanos = micros = millis = secs = mins = hours = days = 0
     if timestr[0] == '-':
         sign = -1
         timestr = timestr[1:]
@@ -87,7 +87,9 @@ def _time_string_to_secs(timestr):
     temp = []
     for c in timestr:
         try:
-            if   c == 'x': millis = float(''.join(temp)); temp = []
+            if   c == 'n': nanos  = float(''.join(temp)); temp = []
+            elif c == 'u': micros = float(''.join(temp)); temp = []
+            elif c == 'x': millis = float(''.join(temp)); temp = []
             elif c == 's': secs   = float(''.join(temp)); temp = []
             elif c == 'm': mins   = float(''.join(temp)); temp = []
             elif c == 'h': hours  = float(''.join(temp)); temp = []
@@ -97,12 +99,15 @@ def _time_string_to_secs(timestr):
             return None
     if temp:
         return None
-    return sign * (millis/1000 + secs + mins*60 + hours*60*60 + days*60*60*24)
+    return sign * (nanos/1E9 + micros/1E6 + millis/1000 + secs +
+                   mins*60 + hours*60*60 + days*60*60*24)
 
 
 def _normalize_timestr(timestr):
     timestr = normalize(timestr)
-    for specifier, aliases in [('x', ['millisecond', 'millisec', 'millis',
+    for specifier, aliases in [('n', ['nanosecond', 'ns']),
+                               ('u', ['microsecond', 'us', 'μs']),
+                               ('x', ['millisecond', 'millisec', 'millis',
                                       'msec', 'ms']),
                                ('s', ['second', 'sec']),
                                ('m', ['minute', 'min']),

utest/utils/test_robottime.py

@@ -100,6 +100,20 @@ def test_timestr_to_secs_with_time_string(self):
                          ('0day 0hour 0minute 0seconds 0millisecond', 0)]:
             assert_equal(timestr_to_secs(inp), exp, inp)
 
+    def test_timestr_to_secs_with_time_string_ns_accuracy(self):
+        for input, expected in [("1 us", 1E-6),
+                                ("1 μs", 1E-6),
+                                ("1 microsecond", 1E-6),
+                                ("1 microseconds", 1E-6),
+                                ("2 us", 2E-6),
+                                ("1 ns", 1E-9),
+                                ("1 nanosecond", 1E-9),
+                                ("1 nanoseconds", 1E-9),
+                                ("2 ns", 2E-9),
+                                ("-100 ns", -100E-9),
+                                ("1.2us", 1.2E-6)]:
+            assert_equal(timestr_to_secs(input, round_to=9), expected)
+
     def test_timestr_to_secs_with_timer_string(self):
         for inp, exp in [('00:00:00', 0),
                          ('00:00:01', 1),