test: add test for testing setup_go function

CMakeLists.txt

@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.19)
+cmake_minimum_required(VERSION 3.29)
 
 project(
   SetupGo

test/CMakeLists.txt

@@ -4,6 +4,7 @@ function(add_cmake_test FILE)
       NAME ${NAME}
       COMMAND ${CMAKE_COMMAND}
         -D CMAKE_MODULE_PATH=${CMAKE_MODULE_PATH}
+        -D CMAKE_BUILD_DIR=${CMAKE_CURRENT_SOURCE_DIR}/build
         -D TEST_MATCHES=^${NAME}$
         -P ${CMAKE_CURRENT_SOURCE_DIR}/${FILE}
     )
@@ -15,3 +16,8 @@ add_cmake_test(
   "Create directory recursively"
   # Add more test cases here.
 )
+
+add_cmake_test(
+  cmake/SetupGoTest.cmake
+  "Set up the latest version of Go"
+)

test/cmake/SetupGoTest.cmake

@@ -0,0 +1,38 @@
+# Matches everything if not defined
+if(NOT TEST_MATCHES)
+  set(TEST_MATCHES ".*")
+endif()
+
+set(TEST_COUNT 0)
+
+include(SetupGo)
+
+if("Set up the latest version of Go" MATCHES ${TEST_MATCHES})
+  math(EXPR TEST_COUNT "${TEST_COUNT} + 1")
+
+  setup_go()
+
+  if(NOT DEFINED GO_EXECUTABLE)
+    message(FATAL_ERROR "The GO_EXECUTABLE variable should be defined")
+  endif()
+
+  if(NOT EXISTS ${GO_EXECUTABLE})
+    message(FATAL_ERROR "The Go executable at '${GO_EXECUTABLE}' should exist")
+  endif()
+
+  if(NOT IS_EXECUTABLE ${GO_EXECUTABLE})
+    message(FATAL_ERROR "The Go executable at '${GO_EXECUTABLE}' should be executable")
+  endif()
+
+  execute_process(
+    COMMAND ${GO_EXECUTABLE} version
+    RESULT_VARIABLE RES
+  )
+  if(NOT RES EQUAL 0)
+    message(FATAL_ERROR "It should not fail to execute the Go executable")
+  endif()
+endif()
+
+if(TEST_COUNT LESS_EQUAL 0)
+  message(FATAL_ERROR "Nothing to test with: ${TEST_MATCHES}")
+endif()