src/dawn/tests/unittests/EnumeratorTests.cpp

// Copyright 2023 The Dawn & Tint Authors
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#include <array>
#include <vector>

#include "dawn/common/Compiler.h"
#include "dawn/common/Enumerator.h"
#include "dawn/common/ityp_array.h"
#include "dawn/common/ityp_span.h"
#include "dawn/common/ityp_vector.h"
#include "gtest/gtest.h"

namespace dawn {
namespace {

class EnumeratorTest : public testing::Test {
  protected:
    template <typename Index, typename Thing, typename Value>
    void Check(Thing thingToEnumerate, const Value* values) {
        size_t i = 0;
        for (auto [index, value] : Enumerate(thingToEnumerate)) {
            ASSERT_EQ(index, Index(i));
            ASSERT_EQ(value, values[i]);
            i++;
        }
    }

    template <typename Thing>
    void CheckEmpty(Thing thingToEnumerate) {
        for ([[maybe_unused]] auto [index, value] : Enumerate(thingToEnumerate)) {
            FAIL();
        }
    }

    using Int = TypedInteger<struct IntT, size_t>;
};

// Test that Enumerate works with std::array
TEST_F(EnumeratorTest, StdArray) {
    // Empty array
    std::array<uint32_t, 0> emptyThing{};
    CheckEmpty(emptyThing);

    // Non-empty array
    std::array<uint32_t, 3> thing = {37, 45, 67};
    Check<size_t>(thing, thing.data());
}

// Test that Enumerate works with std::vector
TEST_F(EnumeratorTest, StdVector) {
    // Empty vector
    std::vector<uint32_t> emptyThing;
    CheckEmpty(emptyThing);

    // Non-empty vector
    std::vector<uint32_t> thing = {{37, 45, 67}};
    Check<size_t>(thing, thing.data());
}

// Test that Enumerate works with ityp::array
TEST_F(EnumeratorTest, ITypArray) {
    // Empty array
    ityp::array<Int, uint32_t, 0> emptyThing;
    CheckEmpty(emptyThing);

    // Non-empty array
    ityp::array<Int, uint32_t, 3> thing = {37u, 45u, 67u};
    Check<Int>(thing, thing.data());
}

// Test that Enumerate works with ityp::span
TEST_F(EnumeratorTest, ITypSpan) {
    // Empty span
    ityp::span<Int, uint32_t> emptyThing;
    CheckEmpty(emptyThing);

    // Empty span for a non-null pointer.
    uint32_t whatever = 923847;
    auto emptyThingWithGarbagePointer = ityp::SpanFromUntyped<Int>(&whatever, 0);
    CheckEmpty(emptyThingWithGarbagePointer);

    // Non-empty span
    std::array<uint32_t, 3> backingArray = {{37, 45, 67}};
    auto thing = ityp::SpanFromUntyped<Int>(backingArray.data(), 3);
    Check<Int>(thing, thing.data());
}

// Test that Enumerate works with ityp::vector
TEST_F(EnumeratorTest, ITypVector) {
    // Empty vector
    ityp::vector<Int, uint32_t> emptyThing;
    CheckEmpty(emptyThing);

    // Non-empty vector
    ityp::vector<Int, uint32_t> thing = {{37, 45, 67}};
    Check<Int>(thing, thing.data());
}

// Test that Enumerate(const container) will give const reference to the values.
TEST_F(EnumeratorTest, ConstContainer) {
    // Non-empty array
    const ityp::array<Int, uint32_t, 3> values = {37u, 45u, 67u};
    for (auto [i, value] : Enumerate(values)) {
        static_assert(std::is_same_v<decltype(value), const uint32_t&>);
    }
}

}  // anonymous namespace
}  // namespace dawn