# -*- coding: utf-8 -*-

"""
Test suite for PEP 380 implementation

adapted from original tests written by Greg Ewing
see <http://www.cosc.canterbury.ac.nz/greg.ewing/python/yield-from/YieldFrom-Python3.1.2-rev5.zip>
"""

import unittest
import inspect

from test.support import captured_stderr, disable_gc, gc_collect
from test import support

class TestPEP380Operation(unittest.TestCase):
    """
    Test semantics.
    """

    def test_delegation_of_initial_next_to_subgenerator(self):
        """
        Test delegation of initial next() call to subgenerator
        """
        trace = []
        def g1():
            trace.append("Starting g1")
            yield from g2()
            trace.append("Finishing g1")
        def g2():
            trace.append("Starting g2")
            yield 42
            trace.append("Finishing g2")
        for x in g1():
            trace.append("Yielded %s" % (x,))
        self.assertEqual(trace,[
            "Starting g1",
            "Starting g2",
            "Yielded 42",
            "Finishing g2",
            "Finishing g1",
        ])

    def test_raising_exception_in_initial_next_call(self):
        """
        Test raising exception in initial next() call
        """
        trace = []
        def g1():
            try:
                trace.append("Starting g1")
                yield from g2()
            finally:
                trace.append("Finishing g1")
        def g2():
            try:
                trace.append("Starting g2")
                raise ValueError("spanish inquisition occurred")
            finally:
                trace.append("Finishing g2")
        try:
            for x in g1():
                trace.append("Yielded %s" % (x,))
        except ValueError as e:
            self.assertEqual(e.args[0], "spanish inquisition occurred")
        else:
            self.fail("subgenerator failed to raise ValueError")
        self.assertEqual(trace,[
            "Starting g1",
            "Starting g2",
            "Finishing g2",
            "Finishing g1",
        ])

    def test_delegation_of_next_call_to_subgenerator(self):
        """
        Test delegation of next() call to subgenerator
        """
        trace = []
        def g1():
            trace.append("Starting g1")
            yield "g1 ham"
            yield from g2()
            yield "g1 eggs"
            trace.append("Finishing g1")
        def g2():
            trace.append("Starting g2")
            yield "g2 spam"
            yield "g2 more spam"
            trace.append("Finishing g2")
        for x in g1():
            trace.append("Yielded %s" % (x,))
        self.assertEqual(trace,[
            "Starting g1",
            "Yielded g1 ham",
            "Starting g2",
            "Yielded g2 spam",
            "Yielded g2 more spam",
            "Finishing g2",
            "Yielded g1 eggs",
            "Finishing g1",
        ])

    def test_raising_exception_in_delegated_next_call(self):
        """
        Test raising exception in delegated next() call
        """
        trace = []
        def g1():
            try:
                trace.append("Starting g1")
                yield "g1 ham"
                yield from g2()
                yield "g1 eggs"
            finally:
                trace.append("Finishing g1")
        def g2():
            try:
                trace.append("Starting g2")
                yield "g2 spam"
                raise ValueError("hovercraft is full of eels")
                yield "g2 more spam"
            finally:
                trace.append("Finishing g2")
        try:
            for x in g1():
                trace.append("Yielded %s" % (x,))
        except ValueError as e:
            self.assertEqual(e.args[0], "hovercraft is full of eels")
        else:
            self.fail("subgenerator failed to raise ValueError")
        self.assertEqual(trace,[
            "Starting g1",
            "Yielded g1 ham",
            "Starting g2",
            "Yielded g2 spam",
            "Finishing g2",
            "Finishing g1",
        ])

    def test_delegation_of_send(self):
        """
        Test delegation of send()
        """
        trace = []
        def g1():
            trace.append("Starting g1")
            x = yield "g1 ham"
            trace.append("g1 received %s" % (x,))
            yield from g2()
            x = yield "g1 eggs"
            trace.append("g1 received %s" % (x,))
            trace.append("Finishing g1")
        def g2():
            trace.append("Starting g2")
            x = yield "g2 spam"
            trace.append("g2 received %s" % (x,))
            x = yield "g2 more spam"
            trace.append("g2 received %s" % (x,))
            trace.append("Finishing g2")
        g = g1()
        y = next(g)
        x = 1
        try:
            while 1:
                y = g.send(x)
                trace.append("Yielded %s" % (y,))
                x += 1
        except StopIteration:
            pass
        self.assertEqual(trace,[
            "Starting g1",
            "g1 received 1",
            "Starting g2",
            "Yielded g2 spam",
            "g2 received 2",
            "Yielded g2 more spam",
            "g2 received 3",
            "Finishing g2",
            "Yielded g1 eggs",
            "g1 received 4",
            "Finishing g1",
        ])

    def test_handling_exception_while_delegating_send(self):
        """
        Test handling exception while delegating 'send'
        """
        trace = []
        def g1():
            trace.append("Starting g1")
            x = yield "g1 ham"
            trace.append("g1 received %s" % (x,))
            yield from g2()
            x = yield "g1 eggs"
            trace.append("g1 received %s" % (x,))
            trace.append("Finishing g1")
        def g2():
            trace.append("Starting g2")
            x = yield "g2 spam"
            trace.append("g2 received %s" % (x,))
            raise ValueError("hovercraft is full of eels")
            x = yield "g2 more spam"
            trace.append("g2 received %s" % (x,))
            trace.append("Finishing g2")
        def run():
            g = g1()
            y = next(g)
            x = 1
            try:
                while 1:
                    y = g.send(x)
                    trace.append("Yielded %s" % (y,))
                    x += 1
            except StopIteration:
                trace.append("StopIteration")
        self.assertRaises(ValueError,run)
        self.assertEqual(trace,[
            "Starting g1",
            "g1 received 1",
            "Starting g2",
            "Yielded g2 spam",
            "g2 received 2",
        ])

    def test_delegating_close(self):
        """
        Test delegating 'close'
        """
        trace = []
        def g1():
            try:
                trace.append("Starting g1")
                yield "g1 ham"
                yield from g2()
                yield "g1 eggs"
            finally:
                trace.append("Finishing g1")
        def g2():
            try:
                trace.append("Starting g2")
                yield "g2 spam"
                yield "g2 more spam"
            finally:
                trace.append("Finishing g2")
        g = g1()
        for i in range(2):
            x = next(g)
            trace.append("Yielded %s" % (x,))
        g.close()
        self.assertEqual(trace,[
            "Starting g1",
            "Yielded g1 ham",
            "Starting g2",
            "Yielded g2 spam",
            "Finishing g2",
            "Finishing g1"
        ])

    def test_handing_exception_while_delegating_close(self):
        """
        Test handling exception while delegating 'close'
        """
        trace = []
        def g1():
            try:
                trace.append("Starting g1")
                yield "g1 ham"
                yield from g2()
                yield "g1 eggs"
            finally:
                trace.append("Finishing g1")
        def g2():
            try:
                trace.append("Starting g2")
                yield "g2 spam"
                yield "g2 more spam"
            finally:
                trace.append("Finishing g2")
                raise ValueError("nybbles have exploded with delight")
        try:
            g = g1()
            for i in range(2):
                x = next(g)
                trace.append("Yielded %s" % (x,))
            g.close()
        except ValueError as e:
            self.assertEqual(e.args[0], "nybbles have exploded with delight")
            self.assertIsInstance(e.__context__, GeneratorExit)
        else:
            self.fail("subgenerator failed to raise ValueError")
        self.assertEqual(trace,[
            "Starting g1",
            "Yielded g1 ham",
            "Starting g2",
            "Yielded g2 spam",
            "Finishing g2",
            "Finishing g1",
        ])

    def test_delegating_throw(self):
        """
        Test delegating 'throw'
        """
        trace = []
        def g1():
            try:
                trace.append("Starting g1")
                yield "g1 ham"
                yield from g2()
                yield "g1 eggs"
            finally:
                trace.append("Finishing g1")
        def g2():
            try:
                trace.append("Starting g2")
                yield "g2 spam"
                yield "g2 more spam"
            finally:
                trace.append("Finishing g2")
        try:
            g = g1()
            for i in range(2):
                x = next(g)
                trace.append("Yielded %s" % (x,))
            e = ValueError("tomato ejected")
            g.throw(e)
        except ValueError as e:
            self.assertEqual(e.args[0], "tomato ejected")
        else:
            self.fail("subgenerator failed to raise ValueError")
        self.assertEqual(trace,[
            "Starting g1",
            "Yielded g1 ham",
            "Starting g2",
            "Yielded g2 spam",
            "Finishing g2",
            "Finishing g1",
        ])

    def test_value_attribute_of_StopIteration_exception(self):
        """
        Test 'value' attribute of StopIteration exception
        """
        trace = []