supposed to read CXX & CC from env, but for some reason this doesnt work ?

Index: tests/tests.rs
--- tests/tests.rs.orig
+++ tests/tests.rs
@@ -69,8 +69,8 @@ fn compile(
     skip_warning_as_error: bool,
 ) {
     let cc = match language {
-        Language::Cxx => env::var("CXX").unwrap_or_else(|_| "g++".to_owned()),
-        Language::C => env::var("CC").unwrap_or_else(|_| "gcc".to_owned()),
+        Language::Cxx => env::var("CXX").unwrap_or_else(|_| "c++".to_owned()),
+        Language::C => env::var("CC").unwrap_or_else(|_| "cc".to_owned()),
         Language::Cython => env::var("CYTHON").unwrap_or_else(|_| "cython".to_owned()),
     };
 
