Adds a simple exercise for structures

exercises/structs/structs1.rs

@@ -0,0 +1,46 @@
+// structs1.rs
+// Address all the TODOs to make the tests pass!
+
+struct ColorClassicStruct {
+    // TODO: Something goes here
+}
+
+struct ColorTupleStruct(/* TODO: Something goes here */);
+
+struct ColorUnitStruct;
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn classic_c_structs() {
+        // TODO: Instantiate a classic c struct!
+        // let green =
+
+        assert_eq!(green.name, "green");
+        assert_eq!(green.hex, "#00FF00");
+    }
+
+    #[test]
+    fn tuple_structs() {
+        // TODO: Instantiate a tuple struct!
+        // For more fun, use the field initialization shorthand.
+        // let green =
+
+        assert_eq!(green.0, "green");
+        assert_eq!(green.1, "#00FF00");
+    }
+
+    #[test]
+    fn unit_structs() {
+        // TODO: Instantiate a unit struct!
+        // let green =
+
+        if let ColorUnitStruct = green {
+            assert!(true);
+        } else {
+            assert!(false);
+        }
+    }
+}