Allow default and minimum timeouts to be specified via environment va…

…riables.

carly/clock.py

@@ -1,14 +1,19 @@
 from __future__ import print_function
 
+from os import environ
+
 from twisted.internet import reactor
 from twisted.internet.defer import Deferred, inlineCallbacks
 
-DEFAULT_TIMEOUT = 0.2
+DEFAULT_TIMEOUT = environ.get('CARLY_DEFAULT_TIMEOUT', 0.2)
 
 
 def withTimeout(deferred, timeout=None):
-    if timeout is None:
-        timeout = DEFAULT_TIMEOUT
+    minimum = environ.get('CARLY_MINIMUM_TIMEOUT')
+    minimum = float(minimum) if minimum else None
+    timeout = timeout or minimum or DEFAULT_TIMEOUT
+    if minimum is not None:
+        timeout = max(timeout, minimum)
     return deferred.addTimeout(timeout, reactor)
 
 

pyproject.toml

@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "carly"
-version = "0.10.2"
+version = "0.11.0"
 description = "A tool for putting messages into and collecting responses from Twisted servers using real networking"
 authors = ["Chris Withers <chris@withers.org>"]
 license = "MIT"

tests/test_clock.py

@@ -1,9 +1,10 @@
-from testfixtures import ShouldRaise
+from testfixtures import ShouldRaise, compare, Replace, not_there
 from twisted.internet import reactor
 from twisted.internet.defer import inlineCallbacks
 from twisted.trial.unittest import TestCase
 
 from carly import cancelDelayedCalls, advanceTime
+from carly.clock import withTimeout
 
 
 def call1(x): pass
@@ -40,3 +41,38 @@ def testLetDeferredsScheduleTheirCalls(self):
         reactor.callLater(0, fireLater, called)
         yield advanceTime(seconds=6)
         assert called
+
+
+class MockDeferred(object):
+
+    def addTimeout(self, timeout, _):
+        self.timeout = timeout
+        return self
+
+
+class TestWithTimeout(TestCase):
+
+    def testNormal(self):
+        with Replace('os.environ.CARLY_MINIMUM_TIMEOUT', not_there, strict=False):
+            actual = withTimeout(MockDeferred())
+        compare(actual.timeout, expected=0.2)
+
+    def testExplicit(self):
+        with Replace('os.environ.CARLY_MINIMUM_TIMEOUT', not_there, strict=False):
+            actual = withTimeout(MockDeferred(), timeout=42)
+        compare(actual.timeout, expected=42)
+
+    def testFromEnv(self):
+        with Replace('os.environ.CARLY_MINIMUM_TIMEOUT', '42', strict=False):
+            actual = withTimeout(MockDeferred())
+        compare(actual.timeout, expected=42)
+
+    def testExplicitLongerThanEnv(self):
+        with Replace('os.environ.CARLY_MINIMUM_TIMEOUT', '1', strict=False):
+            actual = withTimeout(MockDeferred(), timeout=2)
+        compare(actual.timeout, expected=2)
+
+    def testEnvLongerThanExplicit(self):
+        with Replace('os.environ.CARLY_MINIMUM_TIMEOUT', '2', strict=False):
+            actual = withTimeout(MockDeferred(), timeout=1)
+        compare(actual.timeout, expected=2)

tests/test_threads.py

@@ -1,6 +1,6 @@
 from time import sleep
 
-from testfixtures import compare, ShouldRaise
+from testfixtures import compare, ShouldRaise, Replace
 from twisted.internet.defer import inlineCallbacks, TimeoutError
 from twisted.internet.task import LoopingCall
 from twisted.internet.threads import deferToThread