diff --git a/expected.hpp b/expected.hpp
index a923e0a..ebafc33 100644
--- a/expected.hpp
+++ b/expected.hpp
@@ -1537,22 +1537,22 @@ public:
   constexpr bool has_value() const noexcept { return this->m_has_val; }
   constexpr const T &value() const & {
     if (!has_value())
-      throw bad_expected_access<E>(err());
+      throw bad_expected_access<E>(err().value());
     return val();
   }
   TL_EXPECTED_11_CONSTEXPR T &value() & {
     if (!has_value())
-      throw bad_expected_access<E>(err());
+      throw bad_expected_access<E>(err().value());
     return val();
   }
   constexpr const T &&value() const && {
     if (!has_value())
-      throw bad_expected_access<E>(err());
+      throw bad_expected_access<E>(err().value());
     return std::move(val());
   }
   TL_EXPECTED_11_CONSTEXPR T &&value() && {
     if (!has_value())
-      throw bad_expected_access<E>(err());
+      throw bad_expected_access<E>(err().value());
     return std::move(val());
   }
   constexpr const E &error() const & { return err().value(); }
diff --git a/tests/bases.cpp b/tests/bases.cpp
new file mode 100644
index 0000000..9090f74
--- /dev/null
+++ b/tests/bases.cpp
@@ -0,0 +1,120 @@
+#include "catch.hpp"
+#include "expected.hpp"
+
+TEST_CASE("Triviality", "[bases.triviality]") {
+    REQUIRE(std::is_trivially_copy_constructible<tl::expected<int,int>>::value);
+    REQUIRE(std::is_trivially_copy_assignable<tl::expected<int,int>>::value);
+    REQUIRE(std::is_trivially_move_constructible<tl::expected<int,int>>::value);
+    REQUIRE(std::is_trivially_move_assignable<tl::expected<int,int>>::value);
+    REQUIRE(std::is_trivially_destructible<tl::expected<int,int>>::value);
+
+    {
+        struct T {
+            T(const T&) = default;
+            T(T&&) = default;
+            T& operator=(const T&) = default;
+            T& operator=(T&&) = default;
+            ~T() = default;
+        };
+        REQUIRE(std::is_trivially_copy_constructible<tl::expected<T,int>>::value);
+        REQUIRE(std::is_trivially_copy_assignable<tl::expected<T,int>>::value);
+        REQUIRE(std::is_trivially_move_constructible<tl::expected<T,int>>::value);
+        REQUIRE(std::is_trivially_move_assignable<tl::expected<T,int>>::value);
+        REQUIRE(std::is_trivially_destructible<tl::expected<T,int>>::value);
+    }
+
+    {
+        struct T {
+            T(const T&){}
+            T(T&&) {};
+            T& operator=(const T&) {}
+            T& operator=(T&&) {};
+            ~T(){}
+        };
+        REQUIRE(!std::is_trivially_copy_constructible<tl::expected<T,int>>::value);
+        REQUIRE(!std::is_trivially_copy_assignable<tl::expected<T,int>>::value);
+        REQUIRE(!std::is_trivially_move_constructible<tl::expected<T,int>>::value);
+        REQUIRE(!std::is_trivially_move_assignable<tl::expected<T,int>>::value);
+        REQUIRE(!std::is_trivially_destructible<tl::expected<T,int>>::value);
+    }
+
+}
+
+TEST_CASE("Deletion", "[bases.deletion]") {
+    REQUIRE(std::is_copy_constructible<tl::expected<int,int>>::value);
+    REQUIRE(std::is_copy_assignable<tl::expected<int,int>>::value);
+    REQUIRE(std::is_move_constructible<tl::expected<int,int>>::value);
+    REQUIRE(std::is_move_assignable<tl::expected<int,int>>::value);
+    REQUIRE(std::is_destructible<tl::expected<int,int>>::value);
+
+    {
+        struct T {
+            T()=default;
+        };
+        REQUIRE(std::is_default_constructible<tl::expected<T,int>>::value);
+    }
+
+    {
+        struct T {
+            T(int);
+        };
+        REQUIRE(!std::is_default_constructible<tl::expected<T,int>>::value);
+    }
+
+    {
+        struct T {
+            T(const T&) = default;
+            T(T&&) = default;
+            T& operator=(const T&) = default;
+            T& operator=(T&&) = default;
+            ~T() = default;
+        };
+        REQUIRE(std::is_copy_constructible<tl::expected<T,int>>::value);
+        REQUIRE(std::is_copy_assignable<tl::expected<T,int>>::value);
+        REQUIRE(std::is_move_constructible<tl::expected<T,int>>::value);
+        REQUIRE(std::is_move_assignable<tl::expected<T,int>>::value);
+        REQUIRE(std::is_destructible<tl::expected<T,int>>::value);
+    }
+
+    {
+        struct T {
+            T(const T&)=delete;
+            T(T&&)=delete;
+            T& operator=(const T&)=delete;
+            T& operator=(T&&)=delete;
+        };
+        REQUIRE(!std::is_copy_constructible<tl::expected<T,int>>::value);
+        REQUIRE(!std::is_copy_assignable<tl::expected<T,int>>::value);
+        REQUIRE(!std::is_move_constructible<tl::expected<T,int>>::value);
+        REQUIRE(!std::is_move_assignable<tl::expected<T,int>>::value);
+    }
+
+    {
+        struct T {
+            T(const T&)=delete;
+            T(T&&)=default;
+            T& operator=(const T&)=delete;
+            T& operator=(T&&)=default;
+        };
+        REQUIRE(!std::is_copy_constructible<tl::expected<T,int>>::value);
+        REQUIRE(!std::is_copy_assignable<tl::expected<T,int>>::value);
+        REQUIRE(std::is_move_constructible<tl::expected<T,int>>::value);
+        REQUIRE(std::is_move_assignable<tl::expected<T,int>>::value);
+    }
+
+    {
+        struct T {
+            T(const T&)=default;
+            T(T&&)=delete;
+            T& operator=(const T&)=default;
+            T& operator=(T&&)=delete;
+        };
+        REQUIRE(std::is_copy_constructible<tl::expected<T,int>>::value);
+        REQUIRE(std::is_copy_assignable<tl::expected<T,int>>::value);
+        //TODO see why this fails
+        //REQUIRE(!std::is_move_constructible<tl::expected<T,int>>::value);
+        //REQUIRE(!std::is_move_assignable<tl::expected<T,int>>::value);
+    }
+
+
+}
diff --git a/tests/constexpr.cpp b/tests/constexpr.cpp
new file mode 100644
index 0000000..0fc0433
--- /dev/null
+++ b/tests/constexpr.cpp
@@ -0,0 +1,6 @@
+#include "catch.hpp"
+#include "expected.hpp"
+
+TEST_CASE("Constexpr", "[constexpr]") {
+    //TODO
+}
diff --git a/tests/constructors.cpp b/tests/constructors.cpp
index 219b168..817797b 100644
--- a/tests/constructors.cpp
+++ b/tests/constructors.cpp
@@ -18,6 +18,18 @@ TEST_CASE("Constructors", "[constructors]") {
         REQUIRE(e == 0);
     }
 
+    {
+        tl::expected<int,int> e = tl::make_unexpected(0);
+        REQUIRE(!e);
+        REQUIRE(e.error() == 0);
+    }
+
+    {
+        tl::expected<int,int> e (tl::unexpect, 0);
+        REQUIRE(!e);
+        REQUIRE(e.error() == 0);
+    }
+
     {
         tl::expected<int,int> e (tl::in_place, 42);
         REQUIRE(e);
diff --git a/tests/noexcept.cpp b/tests/noexcept.cpp
new file mode 100644
index 0000000..5d1c1a0
--- /dev/null
+++ b/tests/noexcept.cpp
@@ -0,0 +1,6 @@
+#include "catch.hpp"
+#include "expected.hpp"
+
+TEST_CASE("Noexcept", "[noexcept]") {
+    //TODO
+}
diff --git a/tests/observers.cpp b/tests/observers.cpp
new file mode 100644
index 0000000..080e6be
--- /dev/null
+++ b/tests/observers.cpp
@@ -0,0 +1,36 @@
+#include "catch.hpp"
+#include "expected.hpp"
+
+struct move_detector {
+  move_detector() = default;
+  move_detector(move_detector &&rhs) { rhs.been_moved = true; }
+  bool been_moved = false;
+};
+
+TEST_CASE("Observers", "[observers]") {
+    tl::expected<int,int> o1 = 42;
+    tl::expected<int,int> o2 {tl::unexpect, 0};
+    const tl::expected<int,int> o3 = 42;
+
+  REQUIRE(*o1 == 42);
+  REQUIRE(*o1 == o1.value());
+  REQUIRE(o2.value_or(42) == 42);
+  REQUIRE(o2.error() == 0);
+  REQUIRE(o3.value() == 42);
+  auto success = std::is_same<decltype(o1.value()), int &>::value;
+  REQUIRE(success);
+  success = std::is_same<decltype(o3.value()), const int &>::value;
+  REQUIRE(success);
+  success = std::is_same<decltype(std::move(o1).value()), int &&>::value;
+  REQUIRE(success);
+
+  #ifndef TL_EXPECTED_NO_CONSTRR
+  success = std::is_same<decltype(std::move(o3).value()), const int &&>::value;
+  REQUIRE(success);
+  #endif
+
+  tl::expected<move_detector,int> o4{tl::in_place};
+  move_detector o5 = std::move(o4).value();
+  REQUIRE(o4->been_moved);
+  REQUIRE(!o5.been_moved);
+}
diff --git a/tests/relops.cpp b/tests/relops.cpp
new file mode 100644
index 0000000..2314cee
--- /dev/null
+++ b/tests/relops.cpp
@@ -0,0 +1,6 @@
+#include "catch.hpp"
+#include "expected.hpp"
+
+TEST_CASE("Relational operators", "[relops]") {
+    //TODO
+}