diff --git a/.github/workflows/coverage.yml b/.github/workflows/coverage.yml
new file mode 100644
index 0000000..05fb869
--- /dev/null
+++ b/.github/workflows/coverage.yml
@@ -0,0 +1,42 @@
+name: Coverage
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+
+permissions:
+   contents: read  # to fetch code (actions/checkout)
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.head_ref || github.run_id }}
+  cancel-in-progress: true
+
+jobs:
+  codecov:
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+
+    steps:
+    - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683  # v4.2.2
+    - name: Install packages
+      run: sudo apt-get install -y lcov
+
+    - name: Configure
+      run: cmake -DCMAKE_BUILD_TYPE=Coverage -S . -B build
+    - name: Build
+      run: cmake --build build
+    - name: Run Tests
+      working-directory: build
+      run: ctest
+    - name: Generating coverage report
+      run: cmake --build build --target coverage_html
+
+    - name: Upload HTML coverage report
+      uses: actions/upload-artifact@b4b15b8c7c6ac21ea08fcf65892d2ee8f75cf882  # v4.4.3
+      with:
+        name: cov-html
+        path: build/coverage_report/**
+
diff --git a/.gitignore b/.gitignore
index 259148f..c3b5630 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,5 @@
+build/
+
 # Prerequisites
 *.d
 
diff --git a/CMakeLists.txt b/CMakeLists.txt
new file mode 100644
index 0000000..efb3f61
--- /dev/null
+++ b/CMakeLists.txt
@@ -0,0 +1,13 @@
+cmake_minimum_required(VERSION 3.14)
+project(xsf)
+
+# Scipy requ C++17
+# https://docs.scipy.org/doc/scipy/dev/toolchain.html#c-language-standards
+set(CMAKE_CXX_STANDARD 17)
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
+
+include_directories(${CMAKE_SOURCE_DIR}/include)
+
+# Tests
+enable_testing()
+add_subdirectory(tests)
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
new file mode 100644
index 0000000..3018d1a
--- /dev/null
+++ b/tests/CMakeLists.txt
@@ -0,0 +1,23 @@
+# Get googletest
+# https://google.github.io/googletest/quickstart-cmake.html
+include(FetchContent)
+FetchContent_Declare(
+  googletest
+  GIT_REPOSITORY https://github.com/google/googletest.git
+  GIT_TAG        b514bdc898e2951020cbdca1304b75f5950d1f59  # v1.15.2
+)
+# For Windows: Prevent overriding the parent project's compiler/linker settings
+set(gtest_force_shared_crt ON CACHE BOOL "" FORCE)
+FetchContent_MakeAvailable(googletest)
+
+include(GoogleTest)
+include(${CMAKE_SOURCE_DIR}/tests/Coverage.cmake)
+
+# Add Tests
+function(add_gtest test_name)
+    add_executable(${test_name} ${test_name}.cpp)
+    target_link_libraries(${test_name} GTest::gtest_main)
+    gtest_discover_tests(${test_name})
+endfunction()
+
+add_gtest(airy)
diff --git a/tests/Coverage.cmake b/tests/Coverage.cmake
new file mode 100644
index 0000000..b12e021
--- /dev/null
+++ b/tests/Coverage.cmake
@@ -0,0 +1,30 @@
+if(CMAKE_BUILD_TYPE STREQUAL "Coverage")
+
+# Enable coverage compilation option
+if(CMAKE_CXX_COMPILER_ID MATCHES "Clang|GNU")
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} --coverage")
+    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} --coverage")
+endif()
+if(MSVC)
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /coverage")
+    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} /coverage")
+endif()
+
+# Add custom targets for generating coverage reports
+add_custom_target(coverage
+    COMMAND lcov --capture --directory . --output-file coverage.info
+    COMMAND lcov --output-file coverage.info --extract coverage.info '*/include/xsf/*'
+    COMMAND lcov --list coverage.info
+    WORKING_DIRECTORY ${CMAKE_BINARY_DIR}
+    COMMENT "Generating coverage report"
+)
+
+# Generate coverage reports in HTML format
+add_custom_target(coverage_html
+    COMMAND genhtml --demangle-cpp --legend coverage.info --output-directory coverage_report
+    WORKING_DIRECTORY ${CMAKE_BINARY_DIR}
+    COMMENT "Generating HTML coverage report"
+)
+add_dependencies(coverage_html coverage)
+
+endif() # CMAKE_BUILD_TYPE=Coverage
\ No newline at end of file
diff --git a/tests/airy.cpp b/tests/airy.cpp
new file mode 100644
index 0000000..143a0c2
--- /dev/null
+++ b/tests/airy.cpp
@@ -0,0 +1,46 @@
+#include <limits>
+#include <complex>
+#include <gtest/gtest.h>
+#include <xsf/airy.h>
+
+TEST(Airy, BasicAssertions) {
+  const double nan64 = std::numeric_limits<double>::quiet_NaN();
+  const std::complex<double> nan64c(std::nan(""), std::nan(""));
+  double x, ai, aip, bi, bip;
+  
+  x = 0.0;
+  xsf::airy(x, ai, aip, bi, bip);
+  EXPECT_NE(ai, nan64);
+  EXPECT_NE(aip, nan64);
+  EXPECT_NE(bi, nan64);
+  EXPECT_NE(bip, nan64);
+
+  xsf::airye(x, ai, aip, bi, bip);
+  EXPECT_NE(ai, nan64);
+  EXPECT_NE(aip, nan64);
+  EXPECT_NE(bi, nan64);
+  EXPECT_NE(bip, nan64);
+
+  double apt, bpt, ant, bnt;
+  x = 1.0;
+  xsf::itairy(x, apt, bpt, ant, bnt);
+  EXPECT_NE(apt, nan64);
+  EXPECT_NE(bpt, nan64);
+  EXPECT_NE(ant, nan64);
+  EXPECT_NE(bnt, nan64);
+
+  // std::complex
+  std::complex<double> z, cai, caip, cbi, cbip;
+  z = 0.0;
+  xsf::airy(z, cai, caip, cbi, cbip);
+  EXPECT_NE(cai, nan64c);
+  EXPECT_NE(caip, nan64c);
+  EXPECT_NE(cbi, nan64c);
+  EXPECT_NE(cbip, nan64c);
+
+  xsf::airye(z, cai, caip, cbi, cbip);
+  EXPECT_NE(cai, nan64c);
+  EXPECT_NE(caip, nan64c);
+  EXPECT_NE(cbi, nan64c);
+  EXPECT_NE(cbip, nan64c);
+}