// Copyright 2022 The Dawn & Tint Authors
//
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// modification, are permitted provided that the following conditions are met:
//
// 1. Redistributions of source code must retain the above copyright notice, this
//    list of conditions and the following disclaimer.
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// 2. Redistributions in binary form must reproduce the above copyright notice,
//    this list of conditions and the following disclaimer in the documentation
//    and/or other materials provided with the distribution.
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// 3. Neither the name of the copyright holder nor the names of its
//    contributors may be used to endorse or promote products derived from
//    this software without specific prior written permission.
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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#include "src/tint/utils/result.h"

#include <string>

#include "gmock/gmock.h"

namespace tint {
namespace {

struct S {
    int value;
};
static inline bool operator==(const S& a, const S& b) {
    return a.value == b.value;
}

TEST(ResultTest, SuccessInt) {
    auto r = Result<int>(123);
    ASSERT_EQ(r, Success);
    EXPECT_EQ(r.Get(), 123);
}

TEST(ResultTest, SuccessStruct) {
    auto r = Result<S>({123});
    ASSERT_EQ(r, Success);
    EXPECT_EQ(r->value, 123);
    EXPECT_EQ(r, S{123});
}

TEST(ResultTest, Failure) {
    auto r = Result<int>(Failure{});
    EXPECT_NE(r, Success);
}

TEST(ResultTest, CustomFailure) {
    auto r = Result<int, std::string>("oh noes!");
    EXPECT_NE(r, Success);
    EXPECT_EQ(r.Failure(), "oh noes!");
}

TEST(ResultTest, ValueCast) {
    struct X {};
    struct Y : X {};

    Y* y = nullptr;
    auto r_y = Result<Y*>{y};
    auto r_x = Result<X*>{r_y};

    (void)r_x;
    (void)r_y;
}

TEST(ResultTest, CheckResultMacro_ExpressionEvaluatedOnlyOnce) {
    uint32_t count = 0;
    auto f = [&]() -> Result<SuccessType> {
        count++;
        return Failure{"failed"};
    };
    auto caller = [&]() -> Result<SuccessType> {
        TINT_CHECK_RESULT(f());
        return Success;
    };
    ASSERT_NE(caller(), Success);
    EXPECT_EQ(count, 1u);
}

}  // namespace
}  // namespace tint
