Tests: Move AK tests to Tests/AK

Tests/AK/TestBinarySearch.cpp

@@ -0,0 +1,118 @@
+/*
+ * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <LibTest/TestCase.h>
+
+#include <AK/BinarySearch.h>
+#include <AK/Span.h>
+#include <cstring>
+#include <new>
+
+TEST_CASE(vector_ints)
+{
+    Vector<int> ints;
+    ints.append(1);
+    ints.append(2);
+    ints.append(3);
+
+    auto test1 = *binary_search(ints, 1);
+    auto test2 = *binary_search(ints, 2);
+    auto test3 = *binary_search(ints, 3);
+    EXPECT_EQ(test1, 1);
+    EXPECT_EQ(test2, 2);
+    EXPECT_EQ(test3, 3);
+}
+
+TEST_CASE(span_rvalue_reference)
+{
+    Array<long, 3> array { 1, 2, 3 };
+
+    size_t nearby_index = 0;
+    auto* pointer = binary_search(array.span(), 2, &nearby_index);
+
+    EXPECT_EQ(nearby_index, 1u);
+    EXPECT_EQ(pointer, &array[1]);
+}
+
+TEST_CASE(array_doubles)
+{
+    Array<double, 3> array { 1.1, 9.9, 33.33 };
+
+    EXPECT_EQ(binary_search(array, 1.1), &array[0]);
+    EXPECT_EQ(binary_search(array, 33.33), &array[2]);
+    EXPECT_EQ(binary_search(array, 9.9), &array[1]);
+}
+
+TEST_CASE(vector_strings)
+{
+    Vector<String> strings;
+    strings.append("bat");
+    strings.append("cat");
+    strings.append("dog");
+
+    auto string_compare = [](const String& a, const String& b) -> int {
+        return strcmp(a.characters(), b.characters());
+    };
+    auto test1 = *binary_search(strings, String("bat"), nullptr, string_compare);
+    auto test2 = *binary_search(strings, String("cat"), nullptr, string_compare);
+    auto test3 = *binary_search(strings, String("dog"), nullptr, string_compare);
+    EXPECT_EQ(test1, String("bat"));
+    EXPECT_EQ(test2, String("cat"));
+    EXPECT_EQ(test3, String("dog"));
+}
+
+TEST_CASE(single_element)
+{
+    Vector<int> ints;
+    ints.append(1);
+
+    auto test1 = *binary_search(ints, 1);
+    EXPECT_EQ(test1, 1);
+}
+
+TEST_CASE(not_found)
+{
+    Vector<int> ints;
+    ints.append(1);
+    ints.append(2);
+    ints.append(3);
+
+    auto test1 = binary_search(ints, -1);
+    auto test2 = binary_search(ints, 0);
+    auto test3 = binary_search(ints, 4);
+    EXPECT_EQ(test1, nullptr);
+    EXPECT_EQ(test2, nullptr);
+    EXPECT_EQ(test3, nullptr);
+}
+
+TEST_CASE(no_elements)
+{
+    Vector<int> ints;
+
+    auto test1 = binary_search(ints, 1);
+    EXPECT_EQ(test1, nullptr);
+}
+
+TEST_CASE(constexpr_array_search)
+{
+    constexpr Array<int, 3> array = { 1, 17, 42 };
+
+    static_assert(binary_search(array, 42) == &array[2]);
+    static_assert(binary_search(array, 17) == &array[1]);
+    static_assert(binary_search(array, 3) == nullptr);
+}
+
+TEST_CASE(unsigned_to_signed_regression)
+{
+    const Array<u32, 5> input { 0, 1, 2, 3, 4 };
+
+    // The algorithm computes 1 - input[2] = -1, and if this is (incorrectly) cast
+    // to an unsigned then it will look in the wrong direction and miss the 1.
+
+    size_t nearby_index = 1;
+    EXPECT_EQ(binary_search(input, 1u, &nearby_index), &input[1]);
+    EXPECT_EQ(nearby_index, 1u);
+}