diff --git a/test/raw.cpp b/test/raw.cpp
new file mode 100644
index 0000000..81de96d
--- /dev/null
+++ b/test/raw.cpp
@@ -0,0 +1,156 @@
+#include <catch2/catch.hpp>
+#include <endian.h>
+#include <stdexcept>
+#include <stdplus/raw.hpp>
+#include <string_view>
+#include <vector>
+
+namespace stdplus
+{
+namespace raw
+{
+namespace
+{
+
+TEST_CASE("Copy From Empty", "[CopyFrom]")
+{
+    const std::string_view s;
+    CHECK_THROWS_AS(copyFrom<int>(s), std::runtime_error);
+    CHECK(s.empty());
+}
+
+TEST_CASE("Copy From Basic", "[CopyFrom]")
+{
+    int a = 4;
+    const std::string_view s(reinterpret_cast<char*>(&a), sizeof(a));
+    CHECK(a == copyFrom<int>(s));
+}
+
+TEST_CASE("Copy From Partial", "[CopyFrom]")
+{
+    const std::vector<char> s = {'a', 'b', 'c'};
+    CHECK('a' == copyFrom<char>(s));
+    const char s2[] = "def";
+    CHECK('d' == copyFrom<char>(s2));
+}
+
+TEST_CASE("Extract Too Small", "[Extract]")
+{
+    std::string_view s("a");
+    CHECK_THROWS_AS(extract<int>(s), std::runtime_error);
+    CHECK(1 == s.size());
+}
+
+TEST_CASE("Extract Basic", "[Extract]")
+{
+    int a = 4;
+    std::string_view s(reinterpret_cast<char*>(&a), sizeof(a));
+    CHECK(a == extract<int>(s));
+    CHECK(s.empty());
+}
+
+TEST_CASE("Extract Partial", "[Extract]")
+{
+    std::string_view s("abc");
+    CHECK('a' == extract<char>(s));
+    CHECK(2 == s.size());
+}
+
+TEST_CASE("As View Byte", "[AsView]")
+{
+    int32_t a = 4;
+    auto s = asView<uint8_t>(a);
+    CHECK(a == copyFrom<int>(s));
+}
+
+TEST_CASE("As View Int", "[AsView]")
+{
+    int32_t a = 4;
+    auto s = asView<char16_t>(a);
+    CHECK(a == copyFrom<int>(s));
+}
+
+TEST_CASE("As View Arr", "[AsView]")
+{
+    std::vector<uint32_t> arr = {htole32(1), htole32(2)};
+    auto s = asView<char16_t>(arr);
+    REQUIRE(4 == s.size());
+    CHECK(htole16(1) == s[0]);
+    CHECK(htole16(0) == s[1]);
+    CHECK(htole16(2) == s[2]);
+    CHECK(htole16(0) == s[3]);
+}
+
+#ifdef STDPLUS_SPAN_TYPE
+TEST_CASE("Span Extract TooSmall", "[Extract]")
+{
+    const std::vector<char> v = {'c'};
+    span<const char> s = v;
+    CHECK_THROWS_AS(extract<int>(s), std::runtime_error);
+    CHECK(1 == s.size());
+}
+
+TEST_CASE("Span Extract Basic", "[Extract]")
+{
+    const std::vector<int> v = {4};
+    span<const int> s = v;
+    CHECK(v[0] == extract<int>(s));
+    CHECK(s.empty());
+}
+
+TEST_CASE("Span Extract Larger", "[Extract]")
+{
+    const std::vector<int> v{3, 4, 5};
+    span<const int> s = v;
+    CHECK(v[0] == extract<int>(s));
+    CHECK(v.size() - 1 == s.size());
+}
+
+TEST_CASE("As Span const", "[AsSpan]")
+{
+    const uint64_t data = htole64(0xffff0000);
+    auto s = asSpan<uint32_t>(data);
+    CHECK(s.size() == 2);
+    CHECK(s[0] == htole32(0xffff0000));
+    CHECK(s[1] == htole32(0x00000000));
+}
+
+TEST_CASE("As Span Arr const", "[AsSpan]")
+{
+    const std::vector<uint32_t> arr = {htole32(1), htole32(2)};
+    auto s = asSpan<uint16_t>(arr);
+    REQUIRE(4 == s.size());
+    CHECK(htole16(1) == s[0]);
+    CHECK(htole16(0) == s[1]);
+    CHECK(htole16(2) == s[2]);
+    CHECK(htole16(0) == s[3]);
+}
+
+TEST_CASE("As Span", "[AsSpan]")
+{
+    uint64_t data = htole64(0xffff0000);
+    auto s = asSpan<uint16_t>(data);
+    CHECK(s.size() == 4);
+    s[2] = 0xfefe;
+    CHECK(s[0] == htole16(0x0000));
+    CHECK(s[1] == htole16(0xffff));
+    CHECK(s[2] == htole16(0xfefe));
+    CHECK(s[3] == htole16(0x0000));
+}
+
+TEST_CASE("As Span Arr", "[AsSpan]")
+{
+    std::vector<uint32_t> arr = {htole32(1), htole32(2)};
+    auto s = asSpan<uint16_t>(arr);
+    REQUIRE(4 == s.size());
+    CHECK(htole16(1) == s[0]);
+    CHECK(htole16(0) == s[1]);
+    CHECK(htole16(2) == s[2]);
+    CHECK(htole16(0) == s[3]);
+}
+
+#endif
+
+} // namespace
+} // namespace raw
+} // namespace stdplus