Added thread safety test for lambda wrapper (muted for python2.7)

Author: Quentin Pierre

tests/performance/test_lambda_wrapper_thread_safety.py

@@ -0,0 +1,101 @@
+import re
+import time
+# import unittest
+import threading
+from nose import tools as t
+
+from datadog import lambda_stats, datadog_lambda_wrapper
+
+
+class MemoryReporter(object):
+    """ A reporting class that reports to memory for testing. """
+
+    def __init__(self):
+        self.metrics = []
+        self.events = []
+
+    def flush_metrics(self, metrics):
+        self.metrics += metrics
+
+    def flush_events(self, events):
+        self.events += events
+
+
+@datadog_lambda_wrapper
+def wrapped_function(id):
+
+    t.assert_greater(datadog_lambda_wrapper._counter, 1)
+    # Increment
+    lambda_stats.increment("counter", timestamp=12345)
+    time.sleep(0.001)  # sleep makes the os continue another thread
+
+    # Gauge
+    lambda_stats.gauge("gauge_" + str(id), 42)
+    time.sleep(0.001)  # sleep makes the os continue another thread
+
+    # Histogram
+    lambda_stats.histogram("histogram", id, timestamp=12345)
+    time.sleep(0.001)  # sleep makes the os continue another thread
+
+    # Event
+    lambda_stats.event("title", "content")
+
+
+@datadog_lambda_wrapper
+def wrapped_init():
+    pass
+
+
+class TestWrapperThreadSafety(object):
+
+    def test_wrapper_thread_safety(self):
+
+        wrapped_init()  # Empty run to make the initialization
+        lambda_stats.reporter = MemoryReporter()
+        datadog_lambda_wrapper._counter = 1
+
+        for i in range(10000):
+            threading.Thread(target=wrapped_function, args=[i]).start()
+        # Wait all threads to finish
+        time.sleep(10)
+
+        # Flush and check
+        t.assert_equal(datadog_lambda_wrapper._counter, 1)
+        lambda_stats.flush(float("inf"))
+
+        metrics = lambda_stats.reporter.metrics
+        events = lambda_stats.reporter.events
+
+        # Overview
+        t.assert_equal(len(metrics), 10009, len(metrics))
+
+        # Sort metrics
+        counter_metrics = []
+        gauge_metrics = []
+        histogram_metrics = []
+
+        for m in metrics:
+            if re.match("gauge_.*", m['metric']):
+                gauge_metrics.append(m)
+            elif re.match("histogram.*", m['metric']):
+                histogram_metrics.append(m)
+            else:
+                counter_metrics.append(m)
+
+        # Counter
+        t.assert_equal(len(counter_metrics), 1, len(counter_metrics))
+        counter = counter_metrics[0]
+        t.assert_equal(counter['points'][0][1], 10000, counter['points'][0][1])
+
+        # Gauge
+        t.assert_equal(len(gauge_metrics), 10000, len(gauge_metrics))
+
+        # Histogram
+        t.assert_equal(len(histogram_metrics), 8, len(histogram_metrics))
+        count_histogram = filter(lambda x: x['metric'] == "histogram.count", histogram_metrics)[0]
+        t.assert_equal(count_histogram['points'][0][1], 10000, count_histogram['points'][0][1])
+        sum_histogram = filter(lambda x: x['metric'] == "histogram.avg", histogram_metrics)[0]
+        t.assert_equal(sum_histogram['points'][0][1], 4999.5, sum_histogram['points'][0][1])
+
+        # Events
+        t.assert_equal(10000, len(events), len(events))