Added RapidCheck

3 files changed, 39 insertions, 1 deletions

diff --git a/meson.build b/meson.build
index bff85ce..9f860b9 100644
--- a/meson.build
+++ b/meson.build
@@ -3,6 +3,14 @@ project('fg-engine', 'cpp',
 
 cpp = meson.get_compiler('cpp')
 
+cmake = import('cmake')
+
+rc_options = cmake.subproject_options()
+rc_options.add_cmake_defines({'RC_ENABLE_CATCH': 'ON'})
+rapidcheck_proj = cmake.subproject('rapidcheck', options: rc_options)
+rapidcheck_dep = rapidcheck_proj.dependency('rapidcheck')
+rapidcheck_catch_dep = rapidcheck_proj.dependency('rapidcheck_catch')
+
 if cpp.get_id() in ['msvc', 'clang-cl']
   add_project_arguments('/std:c++latest', language: 'cpp')
 else
@@ -25,7 +33,7 @@ catch2_dep = dependency('catch2-with-main')
 
 test_exe = executable('fg-tests',
   sources: files('tests/test_fixed_point.cpp'),
-  dependencies: [sim_core_dep, catch2_dep],
+  dependencies: [sim_core_dep, catch2_dep, rapidcheck_dep, rapidcheck_catch_dep],
 )
 
 test('unit tests', test_exe, args: ['-r', 'automake'])
diff --git a/subprojects/rapidcheck.wrap b/subprojects/rapidcheck.wrap
new file mode 100644
index 0000000..bdd4274
--- /dev/null
+++ b/subprojects/rapidcheck.wrap
@@ -0,0 +1,4 @@
+[wrap-git]
+url = https://github.com/emil-e/rapidcheck.git
+revision = 6e8dadfdafa3a74eabb52ead87f8787f72eccd0b
+clone-recursive = true
diff --git a/tests/test_fixed_point.cpp b/tests/test_fixed_point.cpp
index 8c5c269..87a6ef2 100644
--- a/tests/test_fixed_point.cpp
+++ b/tests/test_fixed_point.cpp
@@ -1,4 +1,5 @@
 #include <catch2/catch_test_macros.hpp>
+#include <rapidcheck/catch.h>
 #include "fixed_point.h"
 
 TEST_CASE("fp_t addition is commutative") {
@@ -96,3 +97,28 @@ TEST_CASE("fp_t division truncates precision below 1 ULP") {
     fp_t c = fp_t::from_raw(0);
     CHECK(a / b == c);
 }
+
+namespace rc {
+    template<>
+    struct Arbitrary<fp_t> {
+        static Gen<fp_t> arbitrary() {
+            return gen::map(gen::arbitrary<std::int32_t>(),
+                            [](std::int32_t raw) { return fp_t::from_raw(raw); });
+        }
+    };
+}
+
+TEST_CASE("fp_t addition is commutative for any bit pattern (fuzzed)") {
+    rc::prop("a + b == b + a",
+        [](const fp_t& a, const fp_t& b) {
+            RC_ASSERT(a + b == b + a);
+        });
+}
+
+TEST_CASE("fp_t division by itself is identity for any nonzero value (fuzzed)") {
+    rc::prop("a / a == from_int(1) when a.raw != 0",
+        [](const fp_t& a) {
+            RC_PRE(a.raw != 0);
+            RC_ASSERT(a / a == fp_t::from_int(1));
+        });
+}