ladybird/AK/Tests/Span.cpp

/*
 * Copyright (c) 2020, the SerenityOS developers.
 * All rights reserved.
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 * Redistribution and use in source and binary forms, with or without
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 *    and/or other materials provided with the distribution.
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 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
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#include <AK/TestSuite.h>

#include <AK/Checked.h>
#include <AK/Span.h>
#include <AK/StdLibExtras.h>

TEST_CASE(default_constructor_is_empty)
{
    Span<int> span;
    EXPECT(span.is_empty());
}

TEST_CASE(span_works_with_constant_types)
{
    const u8 buffer[4] { 1, 2, 3, 4 };
    ReadonlyBytes bytes { buffer, 4 };

    EXPECT(AK::IsConst<AK::RemoveReference<decltype(bytes[1])>::Type>::value);
    EXPECT_EQ(bytes[2], 3);
}

TEST_CASE(span_works_with_mutable_types)
{
    u8 buffer[4] { 1, 2, 3, 4 };
    Bytes bytes { buffer, 4 };

    EXPECT_EQ(bytes[2], 3);
    ++bytes[2];
    EXPECT_EQ(bytes[2], 4);
}

TEST_CASE(iterator_behaves_like_loop)
{
    u8 buffer[256];
    for (int idx = 0; idx < 256; ++idx) {
        buffer[idx] = static_cast<u8>(idx);
    }

    Bytes bytes { buffer, 256 };
    size_t idx = 0;
    for (auto iter = bytes.begin(); iter < bytes.end(); ++iter) {
        EXPECT_EQ(*iter, buffer[idx]);

        ++idx;
    }
}

TEST_CASE(modifying_is_possible)
{
    int values_before[8] = { 1, 2, 3, 4, 5, 6, 7, 8 };
    int values_after[8] = { 7, 6, 5, 4, 3, 2, 1, 0 };

    Span<int> span { values_before, 8 };
    for (auto& value : span) {
        value = 8 - value;
    }

    for (int idx = 0; idx < 8; ++idx) {
        EXPECT_EQ(values_before[idx], values_after[idx]);
    }
}

TEST_CASE(at_and_index_operator_return_same_value)
{
    u8 buffer[256];
    for (int idx = 0; idx < 256; ++idx) {
        buffer[idx] = static_cast<u8>(idx);
    }

    Bytes bytes { buffer, 256 };
    for (int idx = 0; idx < 256; ++idx) {
        EXPECT_EQ(buffer[idx], bytes[idx]);
        EXPECT_EQ(bytes[idx], bytes.at(idx));
    }
}

TEST_CASE(can_subspan_whole_span)
{
    u8 buffer[16];
    Bytes bytes { buffer, 16 };

    Bytes subspan = bytes.subspan(0, 16);

    EXPECT_EQ(subspan.data(), buffer);
    EXPECT_EQ(subspan.size(), 16u);
}

TEST_CASE(can_subspan_as_intended)
{
    const u16 buffer[8] { 1, 2, 3, 4, 5, 6, 7, 8 };

    Span<const u16> span { buffer, 8 };
    auto subspan = span.subspan(3, 2);

    EXPECT_EQ(subspan.size(), 2u);
    EXPECT_EQ(subspan[0], 4);
    EXPECT_EQ(subspan[1], 5);
}

TEST_MAIN(Span)