Add an ALMOST_EQUAL for comparing floats.

fuc2.wrap

@@ -1,5 +1,5 @@
 [wrap-git]
-directory=fuc2-0.1.0
+directory=fuc2-0.2.0
 url=https://lcthw.dev/cpp/fuc2.git
 revision=HEAD
 depth=1

include/fuc2/testing.hpp

@@ -57,6 +57,19 @@ namespace fuc2 {
     }
   }
 
+  void ALMOST_EQUAL(auto v1, auto v2, int decimal_places, const std::string &message="",
+      const std::source_location location = std::source_location::current())
+  {
+    double multiplier = std::pow(10.0, decimal_places);
+    auto r_v1 = std::round(v1 * multiplier) / multiplier;
+    auto r_v2 = std::round(v2 * multiplier) / multiplier;
+
+    if(r_v1 != r_v2) {
+      auto test_value = fmt::format("{} != {} rounded {} places {} != {}", v1, v2, decimal_places, r_v1, r_v2);
+      throw std::runtime_error(craft_error("ALMOST_EQUAL", test_value, message, location));
+    }
+  }
+
   void BLOWS_UP(std::function<void()> cb, const std::string &message="",
       const std::source_location location = std::source_location::current());
 }

meson.build

@@ -1,5 +1,5 @@
 project('fuc2', 'cpp',
-  version: '0.1.0',
+  version: '0.2.0',
   default_options: [
     'cpp_std=c++23',
     'cpp_args=-D_GLIBCXX_DEBUG=1 -D_GLIBCXX_DEBUG_PEDANTIC=1',

tests/sample1.cpp

@@ -42,6 +42,13 @@ namespace sample1 {
     EQUAL(ages.size(), size_t(0), "wrong count");
   }
 
+  void test_almost_equal() {
+    double x = 0.12345;
+    double y = 0.12346;
+
+    ALMOST_EQUAL(x, y, 4);
+  }
+
   void test_push_blows_up() {
     std::deque<float> ages;
 
@@ -60,6 +67,7 @@ namespace sample1 {
       .options={ .fail_fast=false },
       .tests={
         TEST(test_push_pop_back),
+        TEST(test_almost_equal),
         TEST(test_push_pop_front),
         TEST(test_push_blows_up),
       }