LibTest: Add TEST_SETUP macro that runs before all test cases

Author: https://github.com/petelliott
Commit: https://github.com/SerenityOS/serenity/commit/83680934e5f
Pull-request: https://github.com/SerenityOS/serenity/pull/9679
Reviewed-by: https://github.com/ADKaster ✅

Userland/Libraries/LibTest/TestCase.h

@@ -39,9 +39,17 @@ private:
 
 // Helper to hide implementation of TestSuite from users
 void add_test_case_to_suite(const NonnullRefPtr<TestCase>& test_case);
-
+void set_suite_setup_function(Function<void()> setup);
 }
 
+#define TEST_SETUP                                                  \
+    static void __setup();                                          \
+    struct __setup_type {                                           \
+        __setup_type() { Test::set_suite_setup_function(__setup); } \
+    };                                                              \
+    static struct __setup_type __setup_type;                        \
+    static void __setup()
+
 #define __TESTCASE_FUNC(x) __test_##x
 #define __TESTCASE_TYPE(x) __TestCase_##x
 

Userland/Libraries/LibTest/TestSuite.cpp

@@ -7,6 +7,7 @@
 
 #include <LibTest/Macros.h> // intentionally first -- we redefine VERIFY and friends in here
 
+#include <AK/Function.h>
 #include <LibCore/ArgsParser.h>
 #include <LibTest/TestSuite.h>
 #include <stdlib.h>
@@ -49,6 +50,12 @@ void add_test_case_to_suite(const NonnullRefPtr<TestCase>& test_case)
     TestSuite::the().add_case(test_case);
 }
 
+// Declared in TestCase.h
+void set_suite_setup_function(Function<void()> setup)
+{
+    TestSuite::the().set_suite_setup(move(setup));
+}
+
 int TestSuite::main(const String& suite_name, int argc, char** argv)
 {
     m_suite_name = suite_name;
@@ -66,6 +73,9 @@ int TestSuite::main(const String& suite_name, int argc, char** argv)
     args_parser.add_positional_argument(search_string, "Only run matching cases.", "pattern", Core::ArgsParser::Required::No);
     args_parser.parse(argc, argv);
 
+    if (m_setup)
+        m_setup();
+
     const auto& matching_tests = find_cases(search_string, !do_benchmarks_only, !do_tests_only);
 
     if (do_list_cases) {

Userland/Libraries/LibTest/TestSuite.h

@@ -43,6 +43,8 @@ public:
 
     void current_test_case_did_fail() { m_current_test_case_passed = false; }
 
+    void set_suite_setup(Function<void()> setup) { m_setup = move(setup); }
+
 private:
     static TestSuite* s_global;
     NonnullRefPtrVector<TestCase> m_cases;
@@ -50,6 +52,7 @@ private:
     u64 m_benchtime = 0;
     String m_suite_name;
     bool m_current_test_case_passed = true;
+    Function<void()> m_setup;
 };
 
 }