chore(tests): update tests3.rs

added macros assert_eq!() and assert_ne!() and added a further information link

exercises/tests/README.md

@@ -5,3 +5,4 @@ Going out of order from the book to cover tests -- many of the following exercis
 ## Further information
 
 - [Writing Tests](https://doc.rust-lang.org/book/ch11-01-writing-tests.html)
+- [Unit testing](https://doc.rust-lang.org/stable/rust-by-example/testing/unit_testing.html)

exercises/tests/tests3.rs

@@ -1,11 +1,11 @@
 // tests3.rs
 // This test isn't testing our function -- make it do that in such a way that
-// the test passes. Then write a second test that tests whether we get the result
+// the test passes, but just replace the ???
-// we expect to get when we call `is_even(5)`.
 // Execute `rustlings hint tests3` for hints :)
 
 // I AM NOT DONE
 
+// Don't modify this function
 pub fn is_even(num: i32) -> bool {
     num % 2 == 0
 }
@@ -16,11 +16,16 @@ mod tests {
 
     #[test]
     fn is_true_when_even() {
-        assert!();
+        assert!(???);
     }
 
     #[test]
     fn is_false_when_odd() {
-        assert!();
+        assert_eq!(false, ???);
+    }
+
+    #[test]
+    fn is_false_when_odd2() {
+        assert_ne!(true, ???);
     }
 }