src/base/coroutine.test.cc

   1 /*
   2  * Copyright (c) 2018 ARM Limited
   3  * All rights reserved
   4  *
   5  * The license below extends only to copyright in the software and shall
   6  * not be construed as granting a license to any other intellectual
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   8  * to a hardware implementation of the functionality of the software
   9  * licensed hereunder.  You may use the software subject to the license
  10  * terms below provided that you ensure that this notice is replicated
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  12  * modified or unmodified, in source code or in binary form.
  13  *
  14  * Redistribution and use in source and binary forms, with or without
  15  * modification, are permitted provided that the following conditions are
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  23  * this software without specific prior written permission.
  24  *
  25  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  26  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  27  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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  29  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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  31  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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  35  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  36  */
  37
  38 #include <gtest/gtest.h>
  39
  40 #include "base/coroutine.hh"
  41
  42 using namespace m5;
  43
  44 /**
  45  * This test is checking if the Coroutine, once it's created
  46  * it doesn't start since the second argument of the constructor
  47  * (run_coroutine) is set to false
  48  */
  49 TEST(Coroutine, Unstarted)
  50 {
  51     auto yielding_task =
  52     [] (Coroutine<void, void>::CallerType& yield)
  53     {
  54         yield();
  55     };
  56
  57     const bool start_upon_creation = false;
  58     Coroutine<void, void> coro(yielding_task, start_upon_creation);
  59
  60     ASSERT_FALSE(coro.started());
  61 }
  62
  63 /**
  64  * This test is checking if the Coroutine, once it yields
  65  * back to the caller, it is still marked as not finished.
  66  */
  67 TEST(Coroutine, Unfinished)
  68 {
  69     auto yielding_task =
  70     [] (Coroutine<void, void>::CallerType& yield)
  71     {
  72         yield();
  73     };
  74
  75     Coroutine<void, void> coro(yielding_task);
  76     ASSERT_TRUE(coro);
  77 }
  78
  79 /**
  80  * This test is checking the parameter passing interface of a
  81  * coroutine which takes an integer as an argument.
  82  * Coroutine::operator() and CallerType::get() are the tested
  83  * APIS.
  84  */
  85 TEST(Coroutine, Passing)
  86 {
  87     const std::vector<int> input{ 1, 2, 3 };
  88     const std::vector<int> expected_values = input;
  89
  90     auto passing_task =
  91     [&expected_values] (Coroutine<int, void>::CallerType& yield)
  92     {
  93         int argument;
  94
  95         for (const auto expected : expected_values) {
  96             argument = yield.get();
  97             ASSERT_EQ(argument, expected);
  98         }
  99     };
 100
 101     Coroutine<int, void> coro(passing_task);
 102     ASSERT_TRUE(coro);
 103
 104     for (const auto val : input) {
 105         coro(val);
 106     }
 107 }
 108
 109 /**
 110  * This test is checking the yielding interface of a coroutine
 111  * which takes no argument and returns integers.
 112  * Coroutine::get() and CallerType::operator() are the tested
 113  * APIS.
 114  */
 115 TEST(Coroutine, Returning)
 116 {
 117     const std::vector<int> output{ 1, 2, 3 };
 118     const std::vector<int> expected_values = output;
 119
 120     auto returning_task =
 121     [&output] (Coroutine<void, int>::CallerType& yield)
 122     {
 123         for (const auto ret : output) {
 124             yield(ret);
 125         }
 126     };
 127
 128     Coroutine<void, int> coro(returning_task);
 129     ASSERT_TRUE(coro);
 130
 131     for (const auto expected : expected_values) {
 132         int returned = coro.get();
 133         ASSERT_EQ(returned, expected);
 134     }
 135 }
 136
 137 /**
 138  * This test is still supposed to test the returning interface
 139  * of the the Coroutine, proving how coroutine can be used
 140  * for generators.
 141  * The coroutine is computing the first #steps of the fibonacci
 142  * sequence and it is yielding back results one number per time.
 143  */
 144 TEST(Coroutine, Fibonacci)
 145 {
 146     const std::vector<int> expected_values{
 147         1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233 };
 148
 149     const int steps = expected_values.size();
 150
 151     auto fibonacci_task =
 152     [steps] (Coroutine<void, int>::CallerType& yield)
 153     {
 154         int prev = 0;
 155         int current = 1;
 156
 157         for (auto iter = 0; iter < steps; iter++) {
 158             int sum = prev + current;
 159             yield(sum);
 160
 161             prev = current;
 162             current = sum;
 163         }
 164     };
 165
 166     Coroutine<void, int> coro(fibonacci_task);
 167     ASSERT_TRUE(coro);
 168
 169     for (const auto expected : expected_values) {
 170         ASSERT_TRUE(coro);
 171         int returned = coro.get();
 172         ASSERT_EQ(returned, expected);
 173     }
 174 }
 175
 176 /**
 177  * This test is using a bi-channel coroutine (accepting and
 178  * yielding values) for testing a cooperative task.
 179  * The caller and the coroutine have a string each; they are
 180  * composing a new string by merging the strings together one
 181  * character per time.
 182  * The result string is hence passed back and forth between the
 183  * coroutine and the caller.
 184  */
 185 TEST(Coroutine, Cooperative)
 186 {
 187     const std::string caller_str("HloWrd");
 188     const std::string coro_str("el ol!");
 189     const std::string expected("Hello World!");
 190
 191     auto cooperative_task =
 192     [&coro_str] (Coroutine<std::string, std::string>::CallerType& yield)
 193     {
 194         for (auto& appended_c : coro_str) {
 195             auto old_str = yield.get();
 196             yield(old_str + appended_c);
 197         }
 198     };
 199
 200     Coroutine<std::string, std::string> coro(cooperative_task);
 201
 202     std::string result;
 203     for (auto& c : caller_str) {
 204         ASSERT_TRUE(coro);
 205         result += c;
 206         result = coro(result).get();
 207     }
 208
 209     ASSERT_EQ(result, expected);
 210 }
 211
 212 /**
 213  * This test is testing nested coroutines by using one inner and one
 214  * outer coroutine. It basically ensures that yielding from the inner
 215  * coroutine returns to the outer coroutine (mid-layer of execution) and
 216  * not to the outer caller.
 217  */
 218 TEST(Coroutine, Nested)
 219 {
 220     const std::string wrong("Inner");
 221     const std::string expected("Inner + Outer");
 222
 223     auto inner_task =
 224     [] (Coroutine<void, std::string>::CallerType& yield)
 225     {
 226         std::string inner_string("Inner");
 227         yield(inner_string);
 228     };
 229
 230     auto outer_task =
 231     [&inner_task] (Coroutine<void, std::string>::CallerType& yield)
 232     {
 233         Coroutine<void, std::string> coro(inner_task);
 234         std::string inner_string = coro.get();
 235
 236         std::string outer_string("Outer");
 237         yield(inner_string + " + " + outer_string);
 238     };
 239
 240
 241     Coroutine<void, std::string> coro(outer_task);
 242     ASSERT_TRUE(coro);
 243
 244     std::string result = coro.get();
 245
 246     ASSERT_NE(result, wrong);
 247     ASSERT_EQ(result, expected);
 248 }
 249
 250 /**
 251  * This test is stressing the scenario where two distinct fibers are
 252  * calling the same coroutine.  First the test instantiates (and runs) a
 253  * coroutine, then spawns another one and it passes it a reference to
 254  * the first coroutine. Once the new coroutine calls the first coroutine
 255  * and the first coroutine yields, we are expecting execution flow to
 256  * be yielded to the second caller (the second coroutine) and not the
 257  * original caller (the test itself)
 258  */
 259 TEST(Coroutine, TwoCallers)
 260 {
 261     bool valid_return = false;
 262
 263     Coroutine<void, void> callee{[]
 264         (Coroutine<void, void>::CallerType& yield)
 265     {
 266         yield();
 267         yield();
 268     }};
 269
 270     Coroutine<void, void> other_caller{[&callee, &valid_return]
 271         (Coroutine<void, void>::CallerType& yield)
 272     {
 273         callee();
 274         valid_return = true;
 275         yield();
 276     }};
 277
 278     ASSERT_TRUE(valid_return);
 279 }