diff --git a/Makefile b/Makefile
index 73edb673..f27b162a 100755
--- a/Makefile
+++ b/Makefile
@@ -167,11 +167,15 @@ lint-manual: ## Run all manual tools in pre-commit
 
 .PHONY: coverage
 coverage: ## Build and run the tests with the GCOV profile and process the results
-coverage: venv
+coverage: venv $(_build_path)/CMakeCache.txt
 	$(ACTIVATE) cmake --build $(_build_path) --config Gcov
 	$(ACTIVATE) ctest --build-config Gcov --output-on-failure --test-dir $(_build_path)
 	$(ACTIVATE) cmake --build $(_build_path) --config Gcov --target process_coverage
 
+.PHONY: view-coverage
+view-coverage: ## View the coverage report
+	sensible-browser $(_build_path)/coverage/coverage.html
+
 # Help target
 .PHONY: help
 help: ## Show this help.
diff --git a/etc/clang-20-toolchain.cmake b/etc/clang-20-toolchain.cmake
index b41013da..d2be17fa 100644
--- a/etc/clang-20-toolchain.cmake
+++ b/etc/clang-20-toolchain.cmake
@@ -7,5 +7,6 @@ include_guard(GLOBAL)
 
 set(CMAKE_C_COMPILER clang-20)
 set(CMAKE_CXX_COMPILER clang++-20)
+set(GCOV_EXECUTABLE "llvm-cov-20 gcov" CACHE STRING "GCOV executable" FORCE)
 
 include("${CMAKE_CURRENT_LIST_DIR}/clang-flags.cmake")
diff --git a/etc/clang-21-toolchain.cmake b/etc/clang-21-toolchain.cmake
index a2c0b6d7..1f533a40 100644
--- a/etc/clang-21-toolchain.cmake
+++ b/etc/clang-21-toolchain.cmake
@@ -7,5 +7,6 @@ include_guard(GLOBAL)
 
 set(CMAKE_C_COMPILER clang-21)
 set(CMAKE_CXX_COMPILER clang++-21)
+set(GCOV_EXECUTABLE "llvm-cov-21 gcov" CACHE STRING "GCOV executable" FORCE)
 
 include("${CMAKE_CURRENT_LIST_DIR}/clang-flags.cmake")
diff --git a/etc/gcc-flags.cmake b/etc/gcc-flags.cmake
index 1d451f59..641808d1 100644
--- a/etc/gcc-flags.cmake
+++ b/etc/gcc-flags.cmake
@@ -36,7 +36,7 @@ set(CMAKE_CXX_FLAGS_ASAN
 )
 
 set(CMAKE_CXX_FLAGS_GCOV
-    "-O0 -fno-inline -g --coverage -fprofile-abs-path"
+    "-O0 -fno-default-inline -fno-inline -g --coverage -fprofile-abs-path"
     CACHE STRING
     "C++ GCOV Flags"
     FORCE
diff --git a/tests/beman/optional/optional.t.cpp b/tests/beman/optional/optional.t.cpp
index ae2296a8..c76bb6f6 100644
--- a/tests/beman/optional/optional.t.cpp
+++ b/tests/beman/optional/optional.t.cpp
@@ -153,6 +153,53 @@ TEST(OptionalTest, OptionalOfOptional) {
     EXPECT_TRUE(oo2.value() == 43);
 }
 
+TEST(OptionalTest, EmplaceVariadic) {
+    struct for_emplace {
+        int a;
+        int b;
+        int c;
+    } f{4, 5, 6};
+
+    beman::optional::optional<for_emplace> o3;
+    o3.emplace(1, 2, 3);
+    EXPECT_TRUE(o3.has_value());
+
+    beman::optional::optional<for_emplace> engaged{f};
+    engaged.emplace(1, 2, 3);
+    EXPECT_TRUE(engaged.has_value());
+    EXPECT_EQ(engaged->a, 1);
+}
+
+TEST(OptionalTest, EmplaceInitializerList) {
+    struct for_emplace {
+        std::vector<int> v; // something to construct with list
+        std::string      name = "";
+        for_emplace(std::initializer_list<int> l) : v(l) {}
+        for_emplace(std::initializer_list<int> l, std::string n) : v(l), name(n) {}
+    } f{{1, 2, 3}};
+
+    beman::optional::optional<for_emplace> o3;
+    o3.emplace({1, 2, 3});
+    EXPECT_TRUE(o3.has_value());
+
+    beman::optional::optional<for_emplace> engaged{f};
+
+    auto e1 = engaged.emplace({1, 2, 3});
+
+    EXPECT_TRUE(engaged.has_value());
+    EXPECT_EQ(engaged->v[0], 1);
+    EXPECT_EQ(engaged->name, std::string(""));
+    EXPECT_EQ(engaged->v[0], e1.v[0]);
+    EXPECT_EQ(engaged->name, e1.name);
+
+    auto e2 = engaged.emplace({2, 3, 4}, "Name");
+    EXPECT_TRUE(engaged.has_value());
+    EXPECT_EQ(engaged->v[0], 2);
+    EXPECT_EQ(engaged->name, std::string("Name"));
+    EXPECT_EQ(engaged->v[0], e2.v[0]);
+    EXPECT_EQ(engaged->name, e2.name);
+}
+
 TEST(OptionalTest, AssignmentValue) {
     beman::optional::optional<int> o1 = 42;
     beman::optional::optional<int> o2 = 12;
@@ -192,6 +239,15 @@ TEST(OptionalTest, AssignmentValue) {
     o1      = s;
     EXPECT_TRUE(*o1 == 54);
 
+    beman::optional::optional<short> emptyShort;
+    o1 = emptyShort;
+    EXPECT_FALSE(o1);
+
+    o1 = o4;
+    EXPECT_TRUE(*o1 == 42);
+    o1 = std::move(emptyShort);
+    EXPECT_FALSE(o1);
+
     struct not_trivial_copy_assignable {
         int i_;
         constexpr not_trivial_copy_assignable(int i) : i_(i) {}
@@ -243,6 +299,58 @@ TEST(OptionalTest, AssignmentValue) {
     EXPECT_FALSE(o8);
 }
 
+TEST(OptionalTest, ConvertingAssignmentValue) {
+    beman::optional::optional<int> o1 = 42;
+    beman::optional::optional<int> o2;
+
+    short s = 9;
+    o1      = s;
+    o2      = s;
+    EXPECT_TRUE(o1);
+    EXPECT_TRUE(o2);
+}
+
+TEST(OptionalTest, ConvertingValueAssignment) {
+    struct base {};
+
+    struct convertible {
+        operator base() { return base{}; }
+    };
+
+    beman::optional::optional<base> empty;
+    beman::optional::optional<base> engaged(base{});
+
+    empty   = convertible{};
+    engaged = convertible{};
+    EXPECT_TRUE(empty);
+    EXPECT_TRUE(engaged);
+}
+
+TEST(OptionalTest, ValueObserver) {
+    beman::optional::optional<int> empty;
+    beman::optional::optional<int> bound{5};
+    EXPECT_TRUE(bound);
+    EXPECT_FALSE(empty);
+    EXPECT_EQ(*bound, 5);
+    EXPECT_EQ(bound.value(), 5);
+    EXPECT_EQ(std::as_const(bound).value(), 5);
+    EXPECT_EQ(std::move(bound).value(), 5);
+
+    EXPECT_THROW(
+        {
+            try {
+                empty.value();
+            } catch (const beman::optional::bad_optional_access& e) {
+                EXPECT_STREQ("Optional has no value", e.what());
+                throw;
+            }
+        },
+        beman::optional::bad_optional_access);
+
+    EXPECT_THROW({ std::as_const(empty).value(); }, beman::optional::bad_optional_access);
+    EXPECT_THROW({ std::move(empty).value(); }, beman::optional::bad_optional_access);
+}
+
 TEST(OptionalTest, Triviality) {
     EXPECT_TRUE(std::is_trivially_copy_constructible<beman::optional::optional<int>>::value);
     EXPECT_TRUE(std::is_trivially_copy_assignable<beman::optional::optional<int>>::value);
@@ -401,6 +509,16 @@ TEST(OptionalTest, MakeOptional) {
     EXPECT_TRUE(o5->v[1] == 1);
     EXPECT_TRUE(std::get<0>(o5->t) == 2);
     EXPECT_TRUE(std::get<1>(o5->t) == 3);
+
+    struct for_variadic {
+        int a;
+        int b;
+        int c;
+    };
+
+    auto o6 = beman::optional::make_optional<for_variadic>(0, 1, 3);
+    EXPECT_TRUE(o6);
+    EXPECT_EQ(o6->a, 0);
 }
 
 TEST(OptionalTest, Nullopt) {
diff --git a/tests/beman/optional/optional_constexpr.t.cpp b/tests/beman/optional/optional_constexpr.t.cpp
index 00b64aab..626ce9e2 100644
--- a/tests/beman/optional/optional_constexpr.t.cpp
+++ b/tests/beman/optional/optional_constexpr.t.cpp
@@ -161,6 +161,14 @@ consteval bool testConstexprAssignmentValue() {
     o1      = s;
     retval &= (*o1 == 54);
 
+    beman::optional::optional<short> emptyShort;
+    o1 = emptyShort;
+    retval &= !o1.has_value();
+
+    o1 = o4;
+    o1 = std::move(emptyShort);
+    retval &= !o1.has_value();
+
     struct not_trivial_copy_assignable {
         int i_;
         constexpr not_trivial_copy_assignable(int i) : i_(i) {}
diff --git a/tests/beman/optional/optional_ref.t.cpp b/tests/beman/optional/optional_ref.t.cpp
index 0bc9deae..321c0356 100644
--- a/tests/beman/optional/optional_ref.t.cpp
+++ b/tests/beman/optional/optional_ref.t.cpp
@@ -92,6 +92,8 @@ beman::optional::optional<Thing&> process() {
     return t;
 }
 
+beman::optional::optional<Thing&> processEmpty() { return beman::optional::nullopt; }
+
 TEST(OptionalRefTest, BaseDerivedCastConstruction) {
     base                                b;
     derived&                            dref(b); // ok
@@ -145,6 +147,9 @@ TEST(OptionalRefTest, Assignment) {
     o = process(); // well-formed
     EXPECT_TRUE(o);
 
+    o = processEmpty(); // well-formed
+    EXPECT_FALSE(o);
+
     beman::optional::optional<const int&> o2;
     EXPECT_FALSE(o2);
     o2 = [&]() { return i1; }();
@@ -152,6 +157,66 @@ TEST(OptionalRefTest, Assignment) {
     EXPECT_EQ(*o2, 7);
 }
 
+TEST(OptionalRefTest, NullOptAssignment) {
+    beman::optional::optional<int&> i1;
+    EXPECT_FALSE(i1);
+    int i = 5;
+    i1    = i;
+
+    EXPECT_TRUE(i1);
+    i1 = beman::optional::nullopt;
+    EXPECT_FALSE(i1);
+    i1 = i;
+    EXPECT_TRUE(i1);
+}
+
+TEST(OptionalRefTest, ConstRefAssignment) {
+    int                                   i = 7;
+    beman::optional::optional<int&>       i1{i};
+    const beman::optional::optional<int&> i2 = i1;
+
+    beman::optional::optional<const int&> c1;
+    c1 = i2;
+    EXPECT_TRUE(c1);
+    EXPECT_EQ(*c1, 7);
+
+    i = 5;
+    EXPECT_EQ(*c1, 5);
+    const beman::optional::optional<int&> empty(beman::optional::nullopt);
+    c1 = empty;
+    EXPECT_FALSE(c1);
+}
+
+TEST(OptionalRefTest, ConvertingConstRvalRef) {
+    int                                   i = 7;
+    beman::optional::optional<int&>       i1{i};
+    const beman::optional::optional<int&> i2 = i1;
+
+    beman::optional::optional<const int&> c1;
+    c1 = std::move(i2);
+    EXPECT_TRUE(c1);
+    EXPECT_EQ(*c1, 7);
+
+    i = 5;
+    EXPECT_EQ(*c1, 5);
+    const beman::optional::optional<int&> empty(beman::optional::nullopt);
+    c1 = std::move(empty);
+    EXPECT_FALSE(c1);
+}
+
+TEST(OptionalRefTest, NullOptConstruction) {
+    beman::optional::optional<int&> i1(beman::optional::nullopt);
+    EXPECT_FALSE(i1);
+    int i = 5;
+    i1    = i;
+
+    EXPECT_TRUE(i1);
+    i1 = beman::optional::nullopt;
+    EXPECT_FALSE(i1);
+    i1 = i;
+    EXPECT_TRUE(i1);
+}
+
 TEST(OptionalRefTest, RelationalOps) {
     int                             i1 = 4;
     int                             i2 = 42;
@@ -527,17 +592,21 @@ TEST(OptionalRefTest, Observers) {
     beman::optional::optional<int_box&>       ob1 = i1;
     beman::optional::optional<int_box&>       ob2;
     const beman::optional::optional<int_box&> ob3 = i1;
-    success                                       = std::is_same<decltype(ob1->i_), int>::value;
-    static_assert(std::is_same<decltype(ob1->i_), int>::value);
+
+    EXPECT_EQ(ob1->i_, 3);
+    EXPECT_EQ(ob3->i_, 3);
+
+    success = std::is_same_v<decltype(ob1->i_), int>;
+    static_assert(std::is_same_v<decltype(ob1->i_), int>);
     EXPECT_TRUE(success);
-    success = std::is_same<decltype(ob2->i_), int>::value;
-    static_assert(std::is_same<decltype(ob2->i_), int>::value);
+    success = std::is_same_v<decltype(ob2->i_), int>;
+    static_assert(std::is_same_v<decltype(ob2->i_), int>);
     EXPECT_TRUE(success);
-    success = std::is_same<decltype(ob3->i_), int>::value;
-    static_assert(std::is_same<decltype(ob3->i_), int>::value);
+    success = std::is_same_v<decltype(ob3->i_), int>;
+    static_assert(std::is_same_v<decltype(ob3->i_), int>);
     EXPECT_TRUE(success);
-    success = std::is_same<decltype(std::move(ob1)->i_), int>::value;
-    static_assert(std::is_same<decltype(std::move(ob1)->i_), int>::value);
+    success = std::is_same_v<decltype(std::move(ob1)->i_), int>;
+    static_assert(std::is_same_v<decltype(std::move(ob1)->i_), int>);
     EXPECT_TRUE(success);
 }