Updated README files of main repo and exc01

Author: razorblade23

README.md

@@ -10,19 +10,24 @@ These exercises are intended to complement [The Python Ledger](https://thepython
 2. **Install dependencies.** From the repo root:
    ```bash
    python -m venv .venv
-   source .venv/bin/activate   # .venv\Scripts\activate on Windows
+   source .venv/bin/activate
    pip install -r requirements-dev.txt
    ```
 3. **Each exercise directory contains:**
    - `README.md` — the task description
    - `<exercise_name>.py` — a mostly-empty file where you write your code
    - `test_<exercise_name>.py` — the tests that check your code
    - `solution/` — a reference solution, plus the same tests fully unlocked
-4. **Run tests for one exercise** by `cd`-ing into its folder and running:
+4. **Run tests for first exercise** by running:
    ```bash
-   pytest test_<exercise_name>.py -v
+   python check.py 01
    ```
    The first run will fail. That's expected — open the exercise file and write the code needed to make it pass.
+
+   All excercises are marked numericly, so you can use the number, or use the full path to test (TAB completions work too)
+   ```bash
+   python check.py foundations/01_hello_world
+   ```
 5. **Some tests start marked `@pytest.mark.skip`.** This is intentional, same idea as unlocking levels. Once the active test passes, open the spec file, remove the `@pytest.mark.skip(...)` line above the next test, and run again. Keep going until every test in the file passes with no skips left.
 6. **Once you're done**, compare against `solution/` — but not before. There's more than one valid way to pass the tests; the solution is just one example.
 

exercises/foundations/01_hello_world/README.md

@@ -7,10 +7,15 @@ In this directory you'll find 2 other files:
 1. `hello_world.py`
 2. `test_hello_world.py`
 
-Run the test from inside this directory:
+Run the test from the root directory (python-exercises):
+**Note:** try `python3` if the command fails
 
 ```bash
-pytest test_hello_world.py -v
+python check.py 01
+```
+or
+```bash
+python check.py foundations/01_hello_world
 ```
 
 Watch it fail. Right now `hello_world.py` is empty, so nothing gets printed.