Add two very simple examples of using doctest with CMake (#209)

* add some very simple examples of using doctest after having installed it using cmake

* ran clang-format

* update naming in comments

examples/dll_installed_doctest/CMakeLists.txt

@@ -0,0 +1,14 @@
+cmake_minimum_required(VERSION 3.0)
+
+project(example_dll VERSION 0.0.1 LANGUAGES CXX)
+
+find_package(doctest REQUIRED)
+
+add_library("dll" SHARED dll.cpp)
+target_compile_features("dll" PRIVATE cxx_std_17)
+target_compile_definitions("dll" PUBLIC -D_EXPORT)
+target_link_libraries("dll" doctest::doctest)
+
+add_executable(${PROJECT_NAME} main.cpp)
+target_compile_features(${PROJECT_NAME} PRIVATE cxx_std_17)
+target_link_libraries(${PROJECT_NAME} dll)

examples/dll_installed_doctest/dll.cpp

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+#define DOCTEST_CONFIG_IMPLEMENTATION_IN_DLL
+#define DOCTEST_CONFIG_IMPLEMENT
+#include <doctest/doctest.h>
+
+#include "dll.h"
+#include <stdio.h>
+
+extern "C" {
+void say_hello_dll() { printf("%s", "Hello, World!\n"); }
+}
+
+int factorial(int number) {
+  return number < 1 ? 1 : number <= 1 ? number : factorial(number - 1) * number;
+}
+
+TEST_CASE("testing the factorial function") {
+  CHECK(factorial(0) == 1);
+  CHECK(factorial(1) == 1);
+  CHECK(factorial(2) == 2);
+  CHECK(factorial(3) == 6);
+  CHECK(factorial(10) == 3628800);
+}

examples/dll_installed_doctest/dll.h

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+#pragma once
+
+#include "exporting.h"
+
+extern "C" {
+DLL_API void say_hello_dll();
+}

examples/dll_installed_doctest/exporting.h

@@ -0,0 +1,15 @@
+#pragma once
+
+#ifdef _EXPORT
+#ifdef _MSC_VER
+#define DLL_API __declspec(dllexport)
+#elif defined __GNUC__
+#define DLL_API __attribute__((visibility("default")))
+#endif
+#else
+#ifdef _MSC_VER
+#define DLL_API __declspec(dllimport)
+#elif defined __GNUC__
+#define DLL_API __attribute__((visibility("hidden")))
+#endif
+#endif

examples/dll_installed_doctest/main.cpp

@@ -0,0 +1,34 @@
+#define DOCTEST_CONFIG_IMPLEMENTATION_IN_DLL
+#include <doctest/doctest.h>
+
+#include "dll.h"
+
+int main(int argc, char **argv) {
+  doctest::Context context;
+  context.applyCommandLine(argc, argv);
+
+  int res = context.run(); // run doctest
+
+  // important - query flags (and --exit) rely on the user doing this
+  if (context.shouldExit()) {
+    // propagate the result of the tests
+    return res;
+  }
+
+  say_hello_dll(); // test dll func
+}
+
+int square(const int number) { return number * number; }
+
+TEST_CASE("testing the square function") {
+  CHECK(square(2) == 4);
+  CHECK(square(4) == 16);
+  CHECK(square(5) == 25);
+  CHECK(square(8) == 64);
+}
+
+// running notes
+// ./example_dll --no-run (run normal program)
+// ./example_dll --exit (run tests then exit)
+// ./example_dll (run tests then run program)
+// ./example_dll --success (print successful test casts)

examples/executable_installed_doctest/CMakeLists.txt

@@ -0,0 +1,9 @@
+cmake_minimum_required(VERSION 3.0)
+
+project(example_exe VERSION 0.0.1 LANGUAGES CXX)
+
+find_package(doctest REQUIRED)
+
+add_executable(${PROJECT_NAME} main.cpp)
+target_compile_features(${PROJECT_NAME} PRIVATE cxx_std_17)
+target_link_libraries(${PROJECT_NAME} doctest::doctest)

examples/executable_installed_doctest/main.cpp

@@ -0,0 +1,35 @@
+#define DOCTEST_CONFIG_IMPLEMENT
+#include <doctest/doctest.h>
+
+int main(int argc, char **argv) {
+  doctest::Context context;
+  context.applyCommandLine(argc, argv);
+
+  int res = context.run(); // run doctest
+
+  // important - query flags (and --exit) rely on the user doing this
+  if (context.shouldExit()) {
+    // propagate the result of the tests
+    return res;
+  }
+
+  printf("%s", "Hello, World!");
+}
+
+int factorial(const int number) {
+  return number < 1 ? 1 : number <= 1 ? number : factorial(number - 1) * number;
+}
+
+TEST_CASE("testing the factorial function") {
+  CHECK(factorial(0) == 1);
+  CHECK(factorial(1) == 1);
+  CHECK(factorial(2) == 2);
+  CHECK(factorial(3) == 6);
+  CHECK(factorial(10) == 3628800);
+}
+
+// running notes
+// ./example_exe --no-run (run normal program)
+// ./example_exe --exit (run tests then exit)
+// ./example_exe (run tests then run program)
+// ./example_exe --success (print successful test casts)