Performing test on times with data in a fixture

Answers UCL Issue UCL-RITS#92

week05-testing/fixture.yaml

@@ -0,0 +1,21 @@
+- generic:
+    time_range_1: ["2010-01-12 10:00:00", "2010-01-12 12:00:00"]
+    time_range_2: ["2010-01-12 10:30:00", "2010-01-12 10:45:00", 2, 60]
+    expected: 
+        - ["2010-01-12 10:30:00","2010-01-12 10:37:00"]
+        - ["2010-01-12 10:38:00", "2010-01-12 10:45:00"]
+- no_overlap:
+    time_range_1: ["2010-01-12 10:00:00", "2010-01-12 11:00:00"]
+    time_range_2: ["2010-01-12 12:30:00", "2010-01-12 12:45:00", 2, 60]
+    expected: []
+- multiple_overlaps:
+    time_range_1: ["2010-01-12 10:00:00", "2010-01-12 13:00:00", 3, 900]
+    time_range_2: ["2010-01-12 10:40:00", "2010-01-12 11:20:00", 2, 120]
+    expected:
+        - ["2010-01-12 10:40:00","2010-01-12 10:50:00"]
+        - ["2010-01-12 11:05:00", "2010-01-12 11:20:00"]
+- touching:
+    time_range_1: ["2010-01-12 10:00:00", "2010-01-12 11:00:00"]
+    time_range_2: ["2010-01-12 11:00:00", "2010-01-12 12:45:00"]
+    expected: []
+

week05-testing/test_times_fixtures.py

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+"""The file to test times.py"""
+
+#import functions from times.py
+import pytest
+import yaml
+from times import compute_overlap_time, time_range
+
+# get fixture data from yaml file  
+with open("fixture.yaml", 'r') as yamlfile:
+    fixture = yaml.safe_load(yamlfile)
+    print(fixture)
+        # gives a list of dictionaries for each test case
+
+# parametrization of entries
+@pytest.mark.parametrize("test_name", fixture)
+# fixture is a list of dictionaries [{'generic':...}, {'no_overlap':...}, ...]
+
+def test_parametrized_overlap(test_name):
+    # test_name will be a dictionary, e.g. for the first case: {'generic': {'time_range_1':..., 'time_range2':..., 'expected':...}}
+    properties = list(test_name.values())[0]
+    first_range = time_range(*properties['time_range_1'])
+    second_range = time_range(*properties['time_range_2'])
+
+    expected = [(start, stop) for start, stop in properties['expected']]
+    result = compute_overlap_time(first_range, second_range)
+    assert result == expected
+
+#negative test for a date going backwards
+#check that the error message matches with the one raised in time_range function of times.py
+
+# first possible solution
+def test_negative_time_range():
+    with pytest.raises(ValueError) as e:
+        time_range("2010-01-12 10:00:00", "2010-01-12 09:30:00")
+    # lines after the error is raised are not executed in the pytest.raises context, so the assertion has to be outside the "with"    
+    assert e.match('The end of the time range has to come strictly after its start.')
+
+# an alternative solution for using pytest.raises to check that the error message is as expected  
+def test_negative_time_range_alternative():
+    expected_error_message = 'The end of the time range has to come strictly after its start.'
+    with pytest.raises(ValueError, match=expected_error_message):
+        time_range("2010-01-12 10:00:00", "2010-01-12 09:30:00")

week05-testing/times_fixtures.py

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+"""Exercise #61 - Code"""
+
+import datetime
+
+#function to convert the time range into strings of start ta and end tb
+def time_range(start_time, end_time, number_of_intervals=1, gap_between_intervals_s=0):
+    start_time_s = datetime.datetime.strptime(start_time, "%Y-%m-%d %H:%M:%S")
+    end_time_s = datetime.datetime.strptime(end_time, "%Y-%m-%d %H:%M:%S")
+
+    if(start_time_s>=end_time_s):
+        raise ValueError('The end of the time range has to come strictly after its start.')
+
+    d = (end_time_s - start_time_s).total_seconds() / number_of_intervals + gap_between_intervals_s * (1 / number_of_intervals - 1)
+    sec_range = [(start_time_s + datetime.timedelta(seconds=i * d + i * gap_between_intervals_s),
+                  start_time_s + datetime.timedelta(seconds=(i + 1) * d + i * gap_between_intervals_s))
+                 for i in range(number_of_intervals)]
+    return [(ta.strftime("%Y-%m-%d %H:%M:%S"), tb.strftime("%Y-%m-%d %H:%M:%S")) for ta, tb in sec_range]
+
+
+#function to compute the overlap time
+def compute_overlap_time(range1, range2):
+    overlap_time = []
+    for start1, end1 in range1:
+        for start2, end2 in range2:
+
+            # both ranges need to start before the other ends, otherwise there is no overlap!
+            if start1<= end2 and start2 <= end1: 
+                low = max(start1, start2)
+                high = min(end1, end2)
+
+                # in case they touch exactly (end of one is start of the other) --> no overlap
+                if high == low:
+                    continue    # jumps to the next iteration of the loop
+
+                overlap_time.append((low, high))
+
+            #note: when there is no overlap, overlap_time = [] stays
+    return overlap_time
+
+
+# this only runs if this module is run directly, if it is imported somewhere then __name__ == times instead!!
+if __name__ == "__main__":
+    #converts the time ranges into strings
+    large = time_range("2010-01-12 10:00:00", "2010-01-12 12:00:00")
+    short = time_range("2010-01-12 10:30:00", "2010-01-12 10:45:00", 2, 60)
+    print(f"large: {large}")
+        #[('2010-01-12 10:00:00', '2010-01-12 12:00:00')]
+    print(f"short: {short}")
+        #[('2010-01-12 10:30:00', '2010-01-12 10:37:00'), ('2010-01-12 10:38:00', '2010-01-12 10:45:00')]
+
+    # the outputted resulting overlap time 
+    overlap_t = compute_overlap_time(large, short)
+    print(f"The resulting overlaps are {overlap_t}.")
+        #[('2010-01-12 10:30:00', '2010-01-12 10:37:00'), ('2010-01-12 10:38:00', '2010-01-12 10:45:00')]