Tests: Move AK tests to Tests/AK

Tests/AK/TestCircularDuplexStream.cpp

@@ -0,0 +1,63 @@
+/*
+ * Copyright (c) 2020, the SerenityOS developers.
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <LibTest/TestCase.h>
+
+#include <AK/CircularDuplexStream.h>
+
+TEST_CASE(works_like_a_queue)
+{
+    constexpr size_t capacity = 32;
+
+    CircularQueue<u8, capacity> queue;
+    CircularDuplexStream<capacity> stream;
+
+    for (size_t idx = 0; idx < capacity; ++idx) {
+        queue.enqueue(static_cast<u8>(idx % 256));
+        stream << static_cast<u8>(idx % 256);
+    }
+
+    for (size_t idx = 0; idx < capacity; ++idx) {
+        u8 byte = 0;
+        stream >> byte;
+
+        EXPECT_EQ(queue.dequeue(), byte);
+    }
+
+    EXPECT(stream.eof());
+}
+
+TEST_CASE(overwritting_is_well_defined)
+{
+    constexpr size_t half_capacity = 16;
+    constexpr size_t capacity = 2 * half_capacity;
+
+    CircularDuplexStream<capacity> stream;
+
+    for (size_t idx = 0; idx < capacity; ++idx)
+        stream << static_cast<u8>(idx % 256);
+
+    Array<u8, half_capacity> buffer;
+    stream >> buffer;
+
+    for (size_t idx = 0; idx < half_capacity; ++idx)
+        EXPECT_EQ(buffer[idx], idx % 256);
+
+    for (size_t idx = 0; idx < half_capacity; ++idx)
+        stream << static_cast<u8>(idx % 256);
+
+    for (size_t idx = 0; idx < capacity; ++idx) {
+        u8 byte = 0;
+        stream >> byte;
+
+        if (idx < half_capacity)
+            EXPECT_EQ(byte, half_capacity + idx % 256);
+        else
+            EXPECT_EQ(byte, idx % 256 - half_capacity);
+    }
+
+    EXPECT(stream.eof());
+}