diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
new file mode 100644
index 0000000..6c53e81
--- /dev/null
+++ b/.github/workflows/ci.yml
@@ -0,0 +1,31 @@
+name: CI
+
+on:
+  push:
+  pull_request:
+
+permissions:
+  contents: read
+
+jobs:
+  build-and-test:
+    name: macOS / C++23 / CTest
+    runs-on: macos-26
+    timeout-minutes: 10
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Configure
+        run: |
+          cmake -S . -B build \
+            -DDSA_ENABLE_TESTS=ON \
+            -DDSA_ENABLE_WARNINGS=ON \
+            -DCMAKE_BUILD_TYPE=Release
+
+      - name: Build
+        run: cmake --build build --parallel
+
+      - name: Run automated tests
+        run: ctest --test-dir build --output-on-failure --no-tests=error
\ No newline at end of file
diff --git a/src/algorithms/counting_sort.cpp b/src/algorithms/counting_sort.cpp
index 6455bd8..4ab4d01 100644
--- a/src/algorithms/counting_sort.cpp
+++ b/src/algorithms/counting_sort.cpp
@@ -1,5 +1,7 @@
 #include "algorithms/counting_sort.hpp"
 
+#include <stdexcept>
+
 namespace {
 
 int digit_at(int value, int exponent) {
diff --git a/src/algorithms/radix_sort.cpp b/src/algorithms/radix_sort.cpp
index 16477e5..b0515cf 100644
--- a/src/algorithms/radix_sort.cpp
+++ b/src/algorithms/radix_sort.cpp
@@ -2,6 +2,8 @@
 
 #include "algorithms/counting_sort.hpp"
 
+#include <stdexcept>
+
 namespace dsa::algorithms {
 
 void radix_sort(
diff --git a/src/data_structures/direct_access_table.cpp b/src/data_structures/direct_access_table.cpp
index 8f511f1..0486c00 100644
--- a/src/data_structures/direct_access_table.cpp
+++ b/src/data_structures/direct_access_table.cpp
@@ -85,11 +85,7 @@ void DirectAccessTable::direct_access_insert(Node* x) {
         throw std::invalid_argument("x cannot be a null pointer");
     }
     
-    if (x->key < 0) {
-        throw std::invalid_argument("Key cannot be negative");
-    }
-    
-    if (static_cast<std::size_t>(x->key) >= capacity_) {
+    if (x->key >= capacity_) {
         throw std::out_of_range("Key is outside the table range");
     }
 
@@ -100,10 +96,6 @@ void DirectAccessTable::direct_access_delete(Node* x) {
     if (x == nullptr) {
         throw std::invalid_argument("x cannot be a null pointer");
     }
-
-    if (x->key < 0) {
-        throw std::invalid_argument("Key cannot be negative");
-    }
     
     if (static_cast<std::size_t>(x->key) >= capacity_) {
         throw std::out_of_range("Key is outside the table range");
diff --git a/src/data_structures/static_hash_chained_table.cpp b/src/data_structures/static_hash_chained_table.cpp
index 2c799c5..4a8f9df 100644
--- a/src/data_structures/static_hash_chained_table.cpp
+++ b/src/data_structures/static_hash_chained_table.cpp
@@ -229,6 +229,8 @@ std::size_t StaticHashChainedTable::hash_function(std::size_t k) const {
         case HashFunctionType::MultiplyShift:
             return multiply_shift_hash(k);
     }
+
+    throw std::logic_error("Unknown hash function type");
 }
 
 }  // namespace dsa::data_structures
\ No newline at end of file