Make checks for volume pass within reasaonable ranges

Relying on volumes down to the ml allows us to make changes to volume
calculations, and keep the tests withing reasaonable boundaries.

references #74263

tests/char_volume_test.cpp

@@ -44,18 +44,23 @@ TEST_CASE( "character_baseline_volumes", "[volume]" )
     Character &you = get_player_character();
     REQUIRE( you.get_mutations().empty() );
     REQUIRE( you.height() == 175 );
+    CHECK( ( you.get_base_volume() > 55_liter && you.get_base_volume() < 80_liter ) );
 
     REQUIRE( your_height_with_trait( trait_SMALL2 ) == 70 );
-    CHECK( your_volume_with_trait( trait_SMALL2 ) == 23326_ml );
+    CHECK( ( your_volume_with_trait( trait_SMALL2 ) > 20_liter &&
+             your_volume_with_trait( trait_SMALL2 ) < 30_liter ) );
 
     REQUIRE( your_height_with_trait( trait_SMALL ) == 122 );
-    CHECK( your_volume_with_trait( trait_SMALL ) == 42476_ml );
+    CHECK( ( your_volume_with_trait( trait_SMALL ) > 40_liter &&
+             your_volume_with_trait( trait_SMALL ) < 50_liter ) );
 
     REQUIRE( your_height_with_trait( trait_LARGE ) == 227 );
-    CHECK( your_volume_with_trait( trait_LARGE ) == 116034_ml );
+    CHECK( ( your_volume_with_trait( trait_LARGE ) > 100_liter &&
+             your_volume_with_trait( trait_LARGE ) < 120_liter ) );
 
     REQUIRE( your_height_with_trait( trait_HUGE ) == 280 );
-    CHECK( your_volume_with_trait( trait_HUGE ) == 156228_ml );
+    CHECK( ( your_volume_with_trait( trait_HUGE ) > 150_liter &&
+             your_volume_with_trait( trait_HUGE ) < 200_liter ) );
 }
 
 TEST_CASE( "character_at_volume_can_or_cannot_enter_vehicle", "[volume]" )