CON-3821 add unit test instructions to drawing (#3141)

* fix(drawing): add unit tests

* fix(drawing): prettier

Author: pedrodesu

subjects/drawing/README.md

@@ -34,6 +34,14 @@ Each shape must be drawn in a different color.
 
 > Don't forget to add the dependencies in your Cargo.toml.
 
+### Unit Tests
+
+You must implement unit tests within your `geometrical_shapes` module to ensure your logic is sound. Specifically, your tests should:
+
+- Verify that `random` functions never produce points outside the specified image dimensions.
+- Verify that shapes (like `Rectangle`) are correctly initialized even if the points are provided in reverse order.
+- Test edge cases, such as a line where both points are at the same coordinate.
+
 ### Bonus
 
 You may optionally implement the following shapes, including the structures and traits needed to draw them:

subjects/drawing/audit/README.md

@@ -18,6 +18,16 @@
 
 ###### Are the shapes drawn with different colors?
 
+#### Unit Tests
+
+##### Run the command `cargo test`.
+
+###### Do all tests pass without errors?
+
+###### Are there specific tests for the `random` function bounds (e.g., checking that points stay within the image width/height)?
+
+###### Are there tests for shape initialization, such as checking if a `Rectangle` handles inverted coordinates correctly?
+
 #### Bonus
 
 ###### +Can you draw a pentagon?