doctests = '\n\nTest simple loop with conditional\n\n >>> sum(i*i for i in range(100) if i&1 == 1)\n 166650\n\nTest simple nesting\n\n >>> list((i,j) for i in range(3) for j in range(4) )\n [(0, 0), (0, 1), (0, 2), (0, 3), (1, 0), (1, 1), (1, 2), (1, 3), (2, 0), (2, 1), (2, 2), (2, 3)]\n\nTest nesting with the inner expression dependent on the outer\n\n >>> list((i,j) for i in range(4) for j in range(i) )\n [(1, 0), (2, 0), (2, 1), (3, 0), (3, 1), (3, 2)]\n\nMake sure the induction variable is not exposed\n\n >>> i = 20\n >>> sum(i*i for i in range(100))\n 328350\n >>> i\n 20\n\nTest first class\n\n >>> g = (i*i for i in range(4))\n >>> type(g)\n <type \'generator\'>\n >>> list(g)\n [0, 1, 4, 9]\n\nTest direct calls to next()\n\n >>> g = (i*i for i in range(3))\n >>> g.next()\n 0\n >>> g.next()\n 1\n >>> g.next()\n 4\n >>> g.next()\n Traceback (most recent call last):\n File "<pyshell#21>", line 1, in -toplevel-\n g.next()\n StopIteration\n\nDoes it stay stopped?\n\n >>> g.next()\n Traceback (most recent call last):\n File "<pyshell#21>", line 1, in -toplevel-\n g.next()\n StopIteration\n >>> list(g)\n []\n\nTest running gen when defining function is out of scope\n\n >>> def f(n):\n ... return (i*i for i in xrange(n))\n >>> list(f(10))\n [0, 1, 4, 9, 16, 25, 36, 49, 64, 81]\n\n >>> def f(n):\n ... return ((i,j) for i in xrange(3) for j in xrange(n))\n >>> list(f(4))\n [(0, 0), (0, 1), (0, 2), (0, 3), (1, 0), (1, 1), (1, 2), (1, 3), (2, 0), (2, 1), (2, 2), (2, 3)]\n >>> def f(n):\n ... return ((i,j) for i in xrange(3) for j in xrange(4) if j in xrange(n))\n >>> list(f(4))\n [(0, 0), (0, 1), (0, 2), (0, 3), (1, 0), (1, 1), (1, 2), (1, 3), (2, 0), (2, 1), (2, 2), (2, 3)]\n >>> list(f(2))\n [(0, 0), (0, 1), (1, 0), (1, 1), (2, 0), (2, 1)]\n\nVerify that parenthesis are required in a statement\n\n >>> def f(n):\n ... return i*i for i in xrange(n)\n Traceback (most recent call last):\n ...\n SyntaxError: invalid syntax\n\nVerify early binding for the outermost for-expression\n\n >>> x=10\n >>> g = (i*i for i in range(x))\n >>> x = 5\n >>> list(g)\n [0, 1, 4, 9, 16, 25, 36, 49, 64, 81]\n\nVerify that the outermost for-expression makes an immediate check\nfor iterability\n\n >>> (i for i in 6)\n Traceback (most recent call last):\n File "<pyshell#4>", line 1, in -toplevel-\n (i for i in 6)\n TypeError: iteration over non-sequence\n\nVerify late binding for the outermost if-expression\n\n >>> include = (2,4,6,8)\n >>> g = (i*i for i in range(10) if i in include)\n >>> include = (1,3,5,7,9)\n >>> list(g)\n [1, 9, 25, 49, 81]\n\nVerify late binding for the innermost for-expression\n\n >>> g = ((i,j) for i in range(3) for j in range(x))\n >>> x = 4\n >>> list(g)\n [(0, 0), (0, 1), (0, 2), (0, 3), (1, 0), (1, 1), (1, 2), (1, 3), (2, 0), (2, 1), (2, 2), (2, 3)]\n\nVerify re-use of tuples (a side benefit of using genexps over listcomps)\n\n >>> tupleids = map(id, ((i,i) for i in xrange(10)))\n >>> max(tupleids) - min(tupleids)\n 0\n\nVerify that syntax error\'s are raised for genexps used as lvalues\n\n >>> (y for y in (1,2)) = 10\n Traceback (most recent call last):\n ...\n SyntaxError: assign to generator expression not possible\n\n >>> (y for y in (1,2)) += 10\n Traceback (most recent call last):\n ...\n SyntaxError: augmented assign to tuple literal or generator expression not possible\n\n\n\n########### Tests borrowed from or inspired by test_generators.py ############\n\nMake a generator that acts like range()\n\n >>> yrange = lambda n: (i for i in xrange(n))\n >>> list(yrange(10))\n [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]\n\nGenerators always return to the most recent caller:\n\n >>> def creator():\n ... r = yrange(5)\n ... print "creator", r.next()\n ... return r\n >>> def caller():\n ... r = creator()\n ... for i in r:\n ... print "caller", i\n >>> caller()\n creator 0\n caller 1\n caller 2\n caller 3\n caller 4\n\nGenerators can call other generators:\n\n >>> def zrange(n):\n ... for i in yrange(n):\n ... yield i\n >>> list(zrange(5))\n [0, 1, 2, 3, 4]\n\n\nVerify that a gen exp cannot be resumed while it is actively running:\n\n >>> g = (me.next() for i in xrange(10))\n >>> me = g\n >>> me.next()\n Traceback (most recent call last):\n File "<pyshell#30>", line 1, in -toplevel-\n me.next()\n File "<pyshell#28>", line 1, in <generator expression>\n g = (me.next() for i in xrange(10))\n ValueError: generator already executing\n\nVerify exception propagation\n\n >>> g = (10 // i for i in (5, 0, 2))\n >>> g.next()\n 2\n >>> g.next()\n Traceback (most recent call last):\n File "<pyshell#37>", line 1, in -toplevel-\n g.next()\n File "<pyshell#35>", line 1, in <generator expression>\n g = (10 // i for i in (5, 0, 2))\n ZeroDivisionError: integer division or modulo by zero\n >>> g.next()\n Traceback (most recent call last):\n File "<pyshell#38>", line 1, in -toplevel-\n g.next()\n StopIteration\n\nMake sure that None is a valid return value\n\n >>> list(None for i in xrange(10))\n [None, None, None, None, None, None, None, None, None, None]\n\nCheck that generator attributes are present\n\n >>> g = (i*i for i in range(3))\n >>> expected = set([\'gi_frame\', \'gi_running\', \'next\'])\n >>> set(attr for attr in dir(g) if not attr.startswith(\'__\')) >= expected\n True\n\n >>> print g.next.__doc__\n x.next() -> the next value, or raise StopIteration\n >>> import types\n >>> isinstance(g, types.GeneratorType)\n True\n\nCheck the __iter__ slot is defined to return self\n\n >>> iter(g) is g\n True\n\nVerify that the running flag is set properly\n\n >>> g = (me.gi_running for i in (0,1))\n >>> me = g\n >>> me.gi_running\n 0\n >>> me.next()\n 1\n >>> me.gi_running\n 0\n\nVerify that genexps are weakly referencable\n\n >>> import weakref\n >>> g = (i*i for i in range(4))\n >>> wr = weakref.ref(g)\n >>> wr() is g\n True\n >>> p = weakref.proxy(g)\n >>> list(p)\n [0, 1, 4, 9]\n\n\n'
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