rustlings 100 done

exercises/tests/Cargo.toml

@@ -0,0 +1,7 @@
+[package]
+name = "tests7"
+version = "0.0.1"
+edition = "2021"
+[[bin]]
+name = "tests7"
+path = "tests7.rs"

exercises/tests/build.rs

@@ -1,7 +1,6 @@
 //! This is the build script for both tests7 and tests8.
 //!
 //! You should modify this file to make both exercises pass.
-
 fn main() {
     // In tests7, we should set up an environment variable
     // called `TEST_FOO`. Print in the standard output to let
@@ -11,14 +10,14 @@ fn main() {
         .unwrap()
         .as_secs(); // What's the use of this timestamp here?
     let your_command = format!(
-        "Your command here with {}, please checkout exercises/tests/build.rs",
+        "rustc-env=TEST_FOO=",
         timestamp
     );
     println!("cargo:{}", your_command);
 
     // In tests8, we should enable "pass" feature to make the
     // testcase return early. Fill in the command to tell
     // Cargo about that.
-    let your_command = "Your command here, please checkout exercises/tests/build.rs";
+    let your_command = "rustc-cfg=pass";
     println!("cargo:{}", your_command);
 }

exercises/tests/tests7.rs

@@ -34,7 +34,6 @@
 // Execute `rustlings hint tests7` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
 
 fn main() {}
 

exercises/tests/tests8.rs

@@ -7,7 +7,6 @@
 // Execute `rustlings hint tests8` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
 
 fn main() {}
 

exercises/tests/tests9.rs

@@ -27,15 +27,15 @@
 //
 // You should NOT modify any existing code except for adding two lines of attributes.
 
-// I AM NOT DONE
-
 extern "Rust" {
     fn my_demo_function(a: u32) -> u32;
+    #[link_name = "my_demo_function"]
     fn my_demo_function_alias(a: u32) -> u32;
 }
 
 mod Foo {
     // No `extern` equals `extern "Rust"`.
+    #[no_mangle]
     fn my_demo_function(a: u32) -> u32 {
         a
     }