Add test case to return zero on a closed channel #8167
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@@ -60,6 +60,32 @@ TEST(Channel, SufficientBufferSizeDoesntBlock) { | |
| delete ch; | ||
| } | ||
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| // This test tests that CloseChannel returns a value of zero | ||
| // immediately to all receivers that are trying to receive from the channel. | ||
| TEST(Channel, ReceiverGetsZeroOnClosedChannel) { | ||
| const size_t buffer_size = 10; | ||
| auto ch = MakeChannel<size_t>(buffer_size); | ||
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There was a problem hiding this comment. This invariant should be verified with buffered and unbuffered channels. There was a problem hiding this comment. On a side note, correct me if I am wrong @wangkuiyi but for an unbuffered channel, since the buffer size is zero, there would be no residual values. So trying to read from a closed channel should just return a zero value, right ? |
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| std::thread t([&]() { | ||
| // Try to write more than buffer size. | ||
| size_t out; | ||
| for (size_t i = 0; i < 12; ++i) { | ||
| ch->Receive(&out); | ||
| if (i < buffer_size) | ||
| EXPECT_EQ(out, i); // should block after 10 iterations | ||
| else | ||
| EXPECT_EQ(out, 0U); // after close Channel is called, expected value is 0 | ||
| } | ||
| }); | ||
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| for (size_t i = 0; i < buffer_size; ++i) { | ||
| EXPECT_EQ(ch->Send(&i), true); // sending should not block | ||
| } | ||
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| CloseChannel(ch); | ||
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There was a problem hiding this comment. Maybe receive some values before CloseChannel and checks that receivings after CloseChannel return the residual values. There was a problem hiding this comment. Thank you for pointing that out! Will fix it in a commit. |
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| t.join(); | ||
| delete ch; | ||
| } | ||
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| TEST(Channel, ConcurrentSendNonConcurrentReceiveWithSufficientBufferSize) { | ||
| const size_t buffer_size = 10; | ||
| auto ch = MakeChannel<size_t>(buffer_size); | ||
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If the purpose of this PR is to add a unit test to ensure that
then this PR looks too simple to ensure the above two invariants.
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I think one of the axioms was that :
A receive from a closed channel returns the residual values and then zeros.This PR tries to validate that #1 you explained above holds since we aren't explicitly checking for the zero value anywhere else.