diff --git a/flat_set.hpp b/flat_set.hpp
index 9c661e9..f5652f0 100644
--- a/flat_set.hpp
+++ b/flat_set.hpp
@@ -78,19 +78,19 @@ namespace flat_hpp
         }
 
         flat_set(
-            std::initializer_list<value_type> il,
+            std::initializer_list<value_type> ilist,
             const Allocator& a)
         : data_(a) {
-            insert(il.begin(), il.end());
+            insert(ilist);
         }
 
         flat_set(
-            std::initializer_list<value_type> il,
+            std::initializer_list<value_type> ilist,
             const Compare& c = Compare(),
             const Allocator& a = Allocator())
         : data_(a)
         , compare_(c) {
-            insert(il.begin(), il.end());
+            insert(ilist);
         }
 
         iterator begin() noexcept { return data_.begin(); }
@@ -121,36 +121,52 @@ namespace flat_hpp
             return data_.max_size();
         }
 
-        template < typename P
-                 , typename = std::enable_if_t<std::is_constructible<value_type, P>::value> >
-        std::pair<iterator, bool> insert(P&& p) {
-            //TODO(BlackMat): implme
-            return std::make_pair(end(), false);
+        std::pair<iterator, bool> insert(value_type&& value) {
+            const iterator iter = lower_bound(value);
+            return iter == end() || compare_(value, *iter)
+                ? std::make_pair(data_.insert(iter, std::move(value)), true)
+                : std::make_pair(iter, false);
         }
 
-        template < typename P
-                 , typename = std::enable_if_t<std::is_constructible<value_type, P>::value> >
-        std::pair<iterator, bool> insert(const_iterator hint, P&& p) {
-            //TODO(BlackMat): implme
-            return std::make_pair(end(), false);
+        std::pair<iterator, bool> insert(const value_type& value) {
+            const iterator iter = lower_bound(value);
+            return iter == end() || compare_(value, *iter)
+                ? std::make_pair(data_.insert(iter, value), true)
+                : std::make_pair(iter, false);
+        }
+
+        iterator insert(const_iterator hint, value_type&& value) {
+            return (hint == begin() || compare_(*(hint - 1), value))
+                && (hint == end() || compare_(value, *hint))
+                ? data_.insert(hint, std::move(value))
+                : insert(std::move(value)).first;
+        }
+
+        iterator insert(const_iterator hint, const value_type& value) {
+            return (hint == begin() || compare_(*(hint - 1), value))
+                && (hint == end() || compare_(value, *hint))
+                ? data_.insert(hint, value)
+                : insert(value).first;
         }
 
         template < typename InputIter >
         void insert(InputIter first, InputIter last) {
-            for ( auto iter = first; iter != last; ++iter ) {
-                insert(*iter);
+            while ( first != last ) {
+                insert(*first++);
             }
         }
 
+        void insert(std::initializer_list<value_type> ilist) {
+            insert(ilist.begin(), ilist.end());
+        }
+
         template < typename... Args >
         std::pair<iterator, bool> emplace(Args&&... args) {
-            //TODO(BlackMat): implme
             return insert(value_type(std::forward<Args>(args)...));
         }
 
         template < typename... Args >
-        std::pair<iterator, bool> emplace_hint(const_iterator hint, Args&&... args) {
-            //TODO(BlackMat): implme
+        iterator emplace_hint(const_iterator hint, Args&&... args) {
             return insert(hint, value_type(std::forward<Args>(args)...));
         }
 
@@ -159,67 +175,67 @@ namespace flat_hpp
         }
 
         iterator erase(const_iterator iter) {
-            //TODO(BlackMat): implme
-            return end();
+            return data_.erase(iter);
         }
 
         iterator erase(const_iterator first, const_iterator last) {
-            //TODO(BlackMat): implme
-            return end();
+            return data_.erase(first, last);
         }
 
-        iterator erase(const key_type& key) {
-            //TODO(BlackMat): implme
-            return end();
+        size_type erase(const key_type& key) {
+            const iterator iter = find(key);
+            return iter != end()
+                ? (erase(iter), 1)
+                : 0;
         }
 
         void swap(flat_set& other) {
-            //TODO(BlackMat): implme
+            using std::swap;
+            swap(data_, other.data_);
+            swap(compare_, other.compare_);
         }
 
         size_type count(const key_type& key) const {
-            const auto iter = find(key);
+            const const_iterator iter = find(key);
             return iter != end() ? 1 : 0;
         }
 
         iterator find(const key_type& key) {
-            //TODO(BlackMat): implme
-            return end();
+            const iterator iter = lower_bound(key);
+            return iter != end() && !compare_(key, *iter)
+                ? iter
+                : end();
         }
 
         const_iterator find(const key_type& key) const {
-            //TODO(BlackMat): implme
-            return end();
+            const const_iterator iter = lower_bound(key);
+            return iter != end() && !compare_(key, *iter)
+                ? iter
+                : end();
         }
 
         std::pair<iterator, iterator> equal_range(const key_type& key) {
-            //TODO(BlackMat): implme
-            return {end(), end()};
+            return std::equal_range(begin(), end(), key, compare_);
         }
 
         std::pair<const_iterator, const_iterator> equal_range(const key_type& key) const {
-            //TODO(BlackMat): implme
-            return {end(), end()};
+            return std::equal_range(begin(), end(), key, compare_);
         }
 
         iterator lower_bound(const key_type& key) {
-            //TODO(BlackMat): implme
-            return end();
+            return std::lower_bound(begin(), end(), key, compare_);
         }
 
         const_iterator lower_bound(const key_type& key) const {
-            //TODO(BlackMat): implme
-            return end();
+            return std::lower_bound(begin(), end(), key, compare_);
         }
 
         iterator upper_bound(const key_type& key) {
-            //TODO(BlackMat): implme
-            return end();
+            return std::upper_bound(begin(), end(), key, compare_);
         }
 
         const_iterator upper_bound(const key_type& key) const {
-            //TODO(BlackMat): implme
-            return end();
+            return std::upper_bound(begin(), end(), key, compare_);
         }
 
         key_compare key_comp() const {
diff --git a/flat_set_tests.cpp b/flat_set_tests.cpp
index 8e0451b..cafc05a 100644
--- a/flat_set_tests.cpp
+++ b/flat_set_tests.cpp
@@ -18,13 +18,12 @@ namespace
         using value_type = T;
 
         T* allocate(std::size_t n) {
-            (void)n;
-            return nullptr;
+            return static_cast<T*>(std::malloc(sizeof(T) * n));
         }
 
         void deallocate(T* p, std::size_t n) {
-            (void)p;
             (void)n;
+            std::free(p);
         }
     };
 
@@ -69,95 +68,244 @@ TEST_CASE("flat_set") {
     SECTION("ctors") {
         using alloc_t = dummy_allocator<int>;
         using set_t = flat_set<int, std::less<int>, alloc_t>;
+        using set2_t = flat_set<int, std::greater<int>, alloc_t>;
 
         {
             auto s0 = set_t();
-            auto s1 = set_t(alloc_t());
+            auto s1 = set2_t(alloc_t());
             auto s2 = set_t(std::less<int>());
-            auto s3 = set_t(std::less<int>(), alloc_t());
+            auto s3 = set2_t(std::greater<int>(), alloc_t());
         }
 
         {
-            std::vector<int> v;
+            std::vector<int> v{1,2,3};
             auto s0 = set_t(v.cbegin(), v.cend());
-            auto s1 = set_t(v.cbegin(), v.cend(), alloc_t());
+            auto s1 = set2_t(v.cbegin(), v.cend(), alloc_t());
             auto s2 = set_t(v.cbegin(), v.cend(), std::less<int>());
-            auto s3 = set_t(v.cbegin(), v.cend(), std::less<int>(), alloc_t());
+            auto s3 = set2_t(v.cbegin(), v.cend(), std::greater<int>(), alloc_t());
+
+            REQUIRE(std::vector<int>(s0.begin(), s0.end()) == std::vector<int>({1,2,3}));
+            REQUIRE(std::vector<int>(s1.begin(), s1.end()) == std::vector<int>({3,2,1}));
+            REQUIRE(std::vector<int>(s2.begin(), s2.end()) == std::vector<int>({1,2,3}));
+            REQUIRE(std::vector<int>(s3.begin(), s3.end()) == std::vector<int>({3,2,1}));
         }
 
         {
             auto s0 = set_t({0,1,2});
-            auto s1 = set_t({0,1,2}, alloc_t());
+            auto s1 = set2_t({0,1,2}, alloc_t());
             auto s2 = set_t({0,1,2}, std::less<int>());
-            auto s3 = set_t({0,1,2}, std::less<int>(), alloc_t());
+            auto s3 = set2_t({0,1,2}, std::greater<int>(), alloc_t());
+
+            REQUIRE(std::vector<int>(s0.begin(), s0.end()) == std::vector<int>({0,1,2}));
+            REQUIRE(std::vector<int>(s1.begin(), s1.end()) == std::vector<int>({2,1,0}));
+            REQUIRE(std::vector<int>(s2.begin(), s2.end()) == std::vector<int>({0,1,2}));
+            REQUIRE(std::vector<int>(s3.begin(), s3.end()) == std::vector<int>({2,1,0}));
         }
     }
     SECTION("capacity") {
         using set_t = flat_set<int>;
         set_t s0;
-        s0.empty();
-        s0.size();
-        s0.max_size();
+
+        REQUIRE(s0.empty());
+        REQUIRE_FALSE(s0.size());
+        REQUIRE(s0.max_size() == std::allocator<int>().max_size());
+
+        s0.insert(42);
+
+        REQUIRE_FALSE(s0.empty());
+        REQUIRE(s0.size() == 1u);
+        REQUIRE(s0.max_size() == std::allocator<int>().max_size());
+
+        s0.insert(42);
+        REQUIRE(s0.size() == 1u);
+
+        s0.insert(84);
+        REQUIRE(s0.size() == 2u);
+
+        s0.clear();
+
+        REQUIRE(s0.empty());
+        REQUIRE_FALSE(s0.size());
+        REQUIRE(s0.max_size() == std::allocator<int>().max_size());
     }
     SECTION("inserts") {
         struct obj_t {
             obj_t(int i) : i(i) {}
             int i;
+
+            bool operator<(const obj_t& o) const {
+                return i < o.i;
+            }
+
+            bool operator==(const obj_t& o) const {
+                return i == o.i;
+            }
         };
 
         using set_t = flat_set<obj_t>;
 
         {
             set_t s0;
-            s0.insert(42);
-            s0.insert(obj_t(42));
-            s0.insert(s0.cend(), 84);
-            s0.insert(s0.cend(), obj_t(84));
-            s0.emplace(100500);
-            s0.emplace_hint(s0.cend(), 100500);
+
+            auto i0 = s0.insert(1);
+            REQUIRE(s0 == set_t{1});
+            REQUIRE(i0 == std::make_pair(s0.begin(), true));
+
+            auto i1 = s0.insert(obj_t(1));
+            REQUIRE(s0 == set_t{1});
+            REQUIRE(i1 == std::make_pair(s0.begin(), false));
+
+            auto i2 = s0.insert(obj_t(2));
+            REQUIRE(s0 == set_t{1,2});
+            REQUIRE(i2 == std::make_pair(s0.begin() + 1, true));
+
+            s0.insert(s0.cbegin(), 1);
+            s0.insert(s0.cbegin(), 2);
+            s0.insert(s0.cend(), 1);
+            s0.insert(s0.cend(), 2);
+            REQUIRE(s0 == set_t{1,2});
+
+            s0.insert(s0.cbegin(), 0);
+            REQUIRE(s0 == set_t{0,1,2});
+            s0.insert(s0.cend(), 3);
+            REQUIRE(s0 == set_t{0,1,2,3});
+            s0.insert(s0.cbegin(), 4);
+            s0.insert(s0.cend(), -1);
+            REQUIRE(s0 == set_t{-1,0,1,2,3,4});
+
+            s0.insert(s0.cbegin() + 2, obj_t(5));
+            REQUIRE(s0 == set_t{-1,0,1,2,3,4,5});
+            s0.insert(s0.cbegin(), obj_t(-2));
+            REQUIRE(s0 == set_t{-2,-1,0,1,2,3,4,5});
+        }
+
+        {
+            set_t s0;
+
+            auto e0 = s0.emplace(3);
+            REQUIRE(s0 == set_t{3});
+            REQUIRE(e0 == std::make_pair(s0.begin(), true));
+
+            auto e1 = s0.emplace(obj_t(3));
+            REQUIRE(e1 == std::make_pair(s0.begin(), false));
+
+            auto e2 = s0.emplace(4);
+            REQUIRE(s0 == set_t{3,4});
+            REQUIRE(e2 == std::make_pair(s0.begin() + 1, true));
+
+            auto e3 = s0.emplace_hint(s0.cbegin(), 1);
+            REQUIRE(e3 == s0.begin());
+            auto e4 = s0.emplace_hint(s0.cend(), 2);
+            REQUIRE(e4 == s0.begin() + 1);
+            s0.emplace_hint(s0.cbegin(), 5);
+            s0.emplace_hint(s0.cend(), 6);
+            REQUIRE(s0 == set_t{1,2,3,4,5,6});
         }
     }
     SECTION("erasers") {
         using set_t = flat_set<int>;
-        set_t s0;
-        s0.clear();
-        s0.erase(s0.begin());
-        s0.erase(s0.cbegin());
-        s0.erase(s0.begin(), s0.end());
-        s0.erase(s0.cbegin(), s0.cend());
-        s0.erase(42);
-        set_t s1;
-        s0.swap(s1);
-        swap(s0, s1);
+        {
+            set_t s0{1,2,3,4,5};
+            s0.clear();
+            REQUIRE(s0.empty());
+        }
+        {
+            set_t s0{1,2,3,4,5};
+            auto i = s0.erase(s0.find(3));
+            REQUIRE(i == s0.begin() + 2);
+            REQUIRE(s0 == set_t{1,2,4,5});
+        }
+        {
+            set_t s0{1,2,3,4,5};
+            auto i = s0.erase(s0.begin() + 2, s0.end());
+            REQUIRE(i == s0.end());
+            REQUIRE(s0 == set_t{1,2});
+        }
+        {
+            set_t s0{1,2,3,4,5};
+            REQUIRE(s0.erase(2) == 1);
+            REQUIRE(s0.erase(6) == 0);
+            REQUIRE(s0 == set_t{1,3,4,5});
+        }
+        {
+            set_t s0{1,2,3};
+            set_t s1{3,4,5};
+            s0.swap(s1);
+            REQUIRE(s0 == set_t{3,4,5});
+            REQUIRE(s1 == set_t{1,2,3});
+            swap(s1, s0);
+            REQUIRE(s0 == set_t{1,2,3});
+            REQUIRE(s1 == set_t{3,4,5});
+        }
     }
     SECTION("lookup") {
         using set_t = flat_set<int>;
-        set_t s0;
-        s0.count(10);
-        s0.find(10);
-        my_as_const(s0).find(10);
-        s0.equal_range(20);
-        my_as_const(s0).equal_range(20);
-        s0.lower_bound(30);
-        my_as_const(s0).lower_bound(30);
-        s0.upper_bound(30);
-        my_as_const(s0).upper_bound(30);
+        {
+            set_t s0{1,2,3,4,5};
+            REQUIRE(s0.count(3));
+            REQUIRE_FALSE(s0.count(6));
+            REQUIRE(my_as_const(s0).count(5));
+            REQUIRE_FALSE(my_as_const(s0).count(0));
+        }
+        {
+            set_t s0{1,2,3,4,5};
+            REQUIRE(s0.find(2) == s0.begin() + 1);
+            REQUIRE(my_as_const(s0).find(3) == s0.cbegin() + 2);
+            REQUIRE(s0.find(6) == s0.end());
+            REQUIRE(my_as_const(s0).find(0) == s0.cend());
+        }
+        {
+            set_t s0{1,2,3,4,5};
+            REQUIRE(s0.equal_range(3) == std::make_pair(s0.begin() + 2, s0.begin() + 3));
+            REQUIRE(s0.equal_range(6) == std::make_pair(s0.end(), s0.end()));
+            REQUIRE(my_as_const(s0).equal_range(3) == std::make_pair(s0.cbegin() + 2, s0.cbegin() + 3));
+            REQUIRE(my_as_const(s0).equal_range(0) == std::make_pair(s0.cbegin(), s0.cbegin()));
+        }
+        {
+            set_t s0{0,3,6,9};
+            REQUIRE(s0.lower_bound(0) == s0.begin());
+            REQUIRE(s0.lower_bound(1) == s0.begin() + 1);
+            REQUIRE(s0.lower_bound(10) == s0.end());
+            REQUIRE(my_as_const(s0).lower_bound(-1) == s0.cbegin());
+            REQUIRE(my_as_const(s0).lower_bound(7) == s0.cbegin() + 3);
+        }
     }
     SECTION("observers") {
-        using set_t = flat_set<int>;
-        set_t s0;
-        my_as_const(s0).key_comp();
-        my_as_const(s0).value_comp();
+        struct my_less {
+            int i;
+            my_less(int i) : i(i) {}
+            bool operator()(int l, int r) const {
+                return l < r;
+            }
+        };
+        using set_t = flat_set<int, my_less>;
+        set_t s0(my_less(42));
+        REQUIRE(my_as_const(s0).key_comp().i == 42);
+        REQUIRE(my_as_const(s0).value_comp().i == 42);
     }
     SECTION("operators") {
         using set_t = flat_set<int>;
-        set_t s0;
-        set_t s1;
-        REQUIRE(s0 == s1);
-        REQUIRE_FALSE(s0 != s1);
-        REQUIRE_FALSE(s0 < s1);
-        REQUIRE_FALSE(s0 > s1);
-        REQUIRE(s0 <= s1);
-        REQUIRE(s0 >= s1);
+
+        REQUIRE(set_t{1,2,3} == set_t{3,2,1});
+        REQUIRE_FALSE(set_t{1,2,3} == set_t{3,2,4});
+        REQUIRE_FALSE(set_t{1,2,3} == set_t{1,2,3,4});
+
+        REQUIRE(set_t{1,2,3} != set_t{3,2,4});
+        REQUIRE_FALSE(set_t{1,2,3} != set_t{3,2,1});
+
+        REQUIRE(set_t{2,3,4,6} < set_t{2,3,5});
+        REQUIRE(set_t{2,3,4,6} <= set_t{2,3,5});
+        REQUIRE_FALSE(set_t{2,3,5} < set_t{2,3,4,6});
+        REQUIRE_FALSE(set_t{2,3,5} <= set_t{2,3,4,6});
+
+        REQUIRE_FALSE(set_t{2,3,4,6} > set_t{2,3,5});
+        REQUIRE_FALSE(set_t{2,3,4,6} >= set_t{2,3,5});
+        REQUIRE(set_t{2,3,5} > set_t{2,3,4,6});
+        REQUIRE(set_t{2,3,5} >= set_t{2,3,4,6});
+
+        REQUIRE_FALSE(set_t{1,2,3} < set_t{1,2,3});
+        REQUIRE(set_t{1,2,3} <= set_t{1,2,3});
+        REQUIRE_FALSE(set_t{1,2,3} > set_t{1,2,3});
+        REQUIRE(set_t{1,2,3} >= set_t{1,2,3});
     }
 }