Adding cfg_all

Cargo.toml

@@ -55,6 +55,7 @@ clap = "4.0.32"
 # Using features (aka conditional compilation with cfg)
 [features]
 foo = [] # feature has no explicit dependencies
+aa = [] # feature has no explicit dependencies
 
 # Todo: how to use them?
 # Compile time env. vars

src/cfg.rs

@@ -13,11 +13,19 @@ const XX : i32 = 44;
 #[test] fn ex_1_should_fail_with_foo() {
     assert_eq!(XX, 44);
 }
+
 // Using: if cfg!(feature = "foo")
 #[test] fn ex_2_using_if_cfg_and_should_fail_with_foo() {
     if cfg!(feature = "foo") {
         assert_eq!(42, 4);
     } else {
         assert_eq!(42, 42);
     }
+}
+
+// Will fail with 
+// cargo t cfg_all --features "foo aa"
+#[test] fn ex_3_cfg_all() {
+    #[cfg(all(feature= "foo", feature= "aa"))]
+    assert_eq!(42, 43);
 }