TEST_README.md

Testing with CTest

dotenv includes tests to verify the functionality of loading and retrieving environment variables. These tests are written using Google Test and can be run using CTest.

Setting Up Tests

To run the tests, make sure you have Google Test installed or use CMake to download it automatically. Here’s an example CMake setup that downloads Google Test as an external dependency for testing purposes.

1. In your project directory, create a tests/ folder with a CMakeLists.txt file.

2. Inside tests/CMakeLists.txt, add the following:

   # Download and configure Google Test
   include(FetchContent)
   FetchContent_Declare(
     googletest
     URL https://github.com/google/googletest/archive/release-1.12.1.zip
   )
   set(gtest_force_shared_crt ON CACHE BOOL "" FORCE)
   FetchContent_MakeAvailable(googletest)
   
   # Create a test executable
   add_executable(test_dotenv test_dotenv.cpp)
   target_link_libraries(test_dotenv gtest_main)
   add_test(NAME dotenvTests COMMAND test_dotenv)

3. In your main CMakeLists.txt, enable testing and add the tests directory:

   enable_testing()
   add_subdirectory(tests)

Writing Tests

Create a file test_dotenv.cpp inside the tests directory to define test cases. Here’s an example:

#include "dotenv.h"
#include <gtest/gtest.h>

TEST(dotenvTest, LoadFromFile) {
    dotenv env(".env");
    EXPECT_EQ(env.get("DB_HOST", "default_host"), "127.0.0.1");
    EXPECT_EQ(env.get("DB_USER", "default_user"), "admin");
    EXPECT_EQ(env.get("DB_PASSWORD", "default_password"), "secret");
}

TEST(dotenvTest, DefaultValues) {
    dotenv env(".env");
    EXPECT_EQ(env.get("NON_EXISTENT_VAR", "default_value"), "default_value");
}

int main(int argc, char **argv) {
    ::testing::InitGoogleTest(&argc, argv);
    return RUN_ALL_TESTS();
}

Running Tests with CTest

1. Build the Project with CMake, which will automatically set up the test executable:

   mkdir build && cd build
   cmake ..
   make

2. Run Tests using CTest:

   ctest

   CTest will automatically discover and execute the tests, providing a summary of the results.

Interpreting Results

CTest will display output indicating which tests passed or failed. Each test case will show a success message or provide details if a test failed. This feedback ensures that the dotenv library functions as expected across different scenarios.