AK: Add roundtrip tests for BitStream

Tests/AK/TestBitStream.cpp

@@ -8,6 +8,8 @@
 #include <AK/MemoryStream.h>
 #include <LibTest/TestCase.h>
 
+using namespace Test::Randomized;
+
 // Note: This does not do any checks on the internal representation, it just ensures that the behavior of the input and output streams match.
 TEST_CASE(little_endian_bit_stream_input_output_match)
 {
@@ -129,3 +131,90 @@ TEST_CASE(big_endian_bit_stream_input_output_match)
         EXPECT_EQ(0b1101001000100001u, result);
     }
 }
+
+RANDOMIZED_TEST_CASE(roundtrip_u8_little_endian)
+{
+    GEN(n, Gen::unsigned_int(NumericLimits<u8>::max()));
+
+    auto memory_stream = make<AllocatingMemoryStream>();
+    LittleEndianOutputBitStream sut_write { MaybeOwned<Stream>(*memory_stream) };
+    LittleEndianInputBitStream sut_read { MaybeOwned<Stream>(*memory_stream) };
+
+    MUST(sut_write.write_bits(n, 8));
+    MUST(sut_write.flush_buffer_to_stream());
+    auto result = MUST(sut_read.read_bits<u64>(8));
+
+    EXPECT_EQ(result, n);
+}
+
+RANDOMIZED_TEST_CASE(roundtrip_u16_little_endian)
+{
+    GEN(n, Gen::unsigned_int(NumericLimits<u16>::max()));
+
+    auto memory_stream = make<AllocatingMemoryStream>();
+    LittleEndianOutputBitStream sut_write { MaybeOwned<Stream>(*memory_stream) };
+    LittleEndianInputBitStream sut_read { MaybeOwned<Stream>(*memory_stream) };
+
+    MUST(sut_write.write_bits(n, 16));
+    MUST(sut_write.flush_buffer_to_stream());
+    auto result = MUST(sut_read.read_bits<u64>(16));
+
+    EXPECT_EQ(result, n);
+}
+
+RANDOMIZED_TEST_CASE(roundtrip_u32_little_endian)
+{
+    GEN(n, Gen::unsigned_int(NumericLimits<u32>::max()));
+
+    auto memory_stream = make<AllocatingMemoryStream>();
+    LittleEndianOutputBitStream sut_write { MaybeOwned<Stream>(*memory_stream) };
+    LittleEndianInputBitStream sut_read { MaybeOwned<Stream>(*memory_stream) };
+
+    MUST(sut_write.write_bits(n, 32));
+    MUST(sut_write.flush_buffer_to_stream());
+    auto result = MUST(sut_read.read_bits<u64>(32));
+
+    EXPECT_EQ(result, n);
+}
+
+RANDOMIZED_TEST_CASE(roundtrip_u8_big_endian)
+{
+    GEN(n, Gen::unsigned_int(NumericLimits<u8>::max()));
+
+    auto memory_stream = make<AllocatingMemoryStream>();
+    BigEndianOutputBitStream sut_write { MaybeOwned<Stream>(*memory_stream) };
+    BigEndianInputBitStream sut_read { MaybeOwned<Stream>(*memory_stream) };
+
+    MUST(sut_write.write_bits(n, 8));
+    auto result = MUST(sut_read.read_bits<u64>(8));
+
+    EXPECT_EQ(result, n);
+}
+
+RANDOMIZED_TEST_CASE(roundtrip_u16_big_endian)
+{
+    GEN(n, Gen::unsigned_int(NumericLimits<u16>::max()));
+
+    auto memory_stream = make<AllocatingMemoryStream>();
+    BigEndianOutputBitStream sut_write { MaybeOwned<Stream>(*memory_stream) };
+    BigEndianInputBitStream sut_read { MaybeOwned<Stream>(*memory_stream) };
+
+    MUST(sut_write.write_bits(n, 16));
+    auto result = MUST(sut_read.read_bits<u64>(16));
+
+    EXPECT_EQ(result, n);
+}
+
+RANDOMIZED_TEST_CASE(roundtrip_u32_big_endian)
+{
+    GEN(n, Gen::unsigned_int(NumericLimits<u32>::max()));
+
+    auto memory_stream = make<AllocatingMemoryStream>();
+    BigEndianOutputBitStream sut_write { MaybeOwned<Stream>(*memory_stream) };
+    BigEndianInputBitStream sut_read { MaybeOwned<Stream>(*memory_stream) };
+
+    MUST(sut_write.write_bits(n, 32));
+    auto result = MUST(sut_read.read_bits<u64>(32));
+
+    EXPECT_EQ(result, n);
+}