feat: cargo + testing

Cargo.toml

@@ -2,6 +2,7 @@
 name = "rust-by-example"
 version = "0.1.0"
 edition = "2021"
+default-run = "rust-by-example"
 
 [dependencies]
 # clap = "2.27.1" # from crates.io

src/bin/secondary_main.rs

@@ -0,0 +1,4 @@
+fn main() {
+    println!("This was ran with '$ cargo run --bin secondary_main'");
+    println!("This is a secondary main!");
+}

src/main.rs

@@ -18,6 +18,10 @@
 // mod exercises;
 mod concepts;
 
+#[cfg(test)]
+#[path = "./test/basic_test.rs"]
+mod test;
+
 fn main() {
     // helloworld::hello_world_module();
     // primitives::primitives_module();

src/test/basic_test.rs

@@ -0,0 +1,14 @@
+#[cfg(test)]
+pub mod tests {
+    #[test]
+    fn test_success() {
+        let my_hello = "Hello world!";
+        assert_eq!(my_hello, "Hello world!");
+    }
+
+    #[test]
+    fn test_failure() {
+        let my_hello = "ef u world!";
+        assert_eq!(my_hello, "Hello world!");
+    }
+}