Fix path lookup for python_versions.json file

python/docker/test_wheels/scripts/README.md

@@ -2,15 +2,29 @@
 
 ## Installation
 
-For regular use:
-```
+**Important:** This package requires access to the `python_versions.json` configuration file in the opm-simulators repository. Choose one of these installation methods:
+
+### Option 1: Install within repository (Recommended)
+```bash
+# Create venv inside the opm-simulators repository
+$ cd /path/to/opm-simulators/python/docker/test_wheels/scripts
 $ python -m venv .venv
 $ source .venv/bin/activate
 $ pip install .    # Installs package and dependencies
 ```
 
-For development (editable install with locked dependency versions):
+### Option 2: Global installation with environment variable
+```bash
+# Install anywhere, but set environment variable
+$ python -m venv .venv
+$ source .venv/bin/activate
+$ pip install .
+$ export OPM_SIMULATORS_ROOT=/path/to/opm-simulators
 ```
+
+### For development (editable install with locked dependency versions):
+```bash
+$ cd /path/to/opm-simulators/python/docker/test_wheels/scripts
 $ uv venv
 $ uv sync          # Installs package in editable mode with exact versions from uv.lock
 $ source .venv/bin/activate
@@ -100,3 +114,34 @@ $ opm-wheels show-wheel-files \
     opm_simulators-2025.10-cp312-cp312-manylinux_2_27_x86_64.whl
 ```
 
+## Troubleshooting
+
+### FileNotFoundError: Could not locate python_versions.json
+
+This error occurs when the CLI cannot find the configuration file. Solutions:
+
+1. **Run from within the repository:**
+   ```bash
+   cd /path/to/opm-simulators
+   cd python/docker/test_wheels/scripts
+   source .venv/bin/activate
+   opm-wheels run-docker-image --help
+   ```
+
+2. **Set environment variable for global installations:**
+   ```bash
+   export OPM_SIMULATORS_ROOT=/path/to/opm-simulators
+   opm-wheels run-docker-image --help
+   ```
+
+3. **Verify the configuration file exists:**
+   ```bash
+   ls /path/to/opm-simulators/python/docker/python_versions.json
+   ```
+
+### RuntimeError: Not a valid Git repository
+
+This error means you're not inside a Git repository. Either:
+- Navigate to the opm-simulators repository directory, or  
+- Use the `OPM_SIMULATORS_ROOT` environment variable method
+

python/docker/test_wheels/scripts/src/opm_wheels/config_reader.py

@@ -4,14 +4,28 @@ from pathlib import Path
 from typing import Dict, List
 
 from opm_wheels.constants import PythonVersion
+from opm_wheels.helpers import get_git_root
 
 
 def get_config_path() -> Path:
     """Get the path to the python_versions.json config file."""
-    # Go up from docker/test_wheels/scripts/src/opm_wheels to docker root
-    current_dir = Path(__file__).parent
-    config_path = current_dir / ".." / ".." / ".." / ".." / "python_versions.json"
-    return config_path.resolve()
+    try:
+        # Try to find git root (works when inside repo)
+        repo_root = get_git_root()
+        return repo_root / "python/docker/python_versions.json"
+    except RuntimeError:
+        # Fallback to environment variable for global installations
+        env_root = os.environ.get('OPM_SIMULATORS_ROOT')
+        if env_root:
+            repo_root = Path(env_root)
+            config_path = repo_root / "python/docker/python_versions.json"
+            if config_path.exists():
+                return config_path
+        
+        raise FileNotFoundError(
+            "Could not locate python_versions.json. Either run from within "
+            "opm-simulators repository or set OPM_SIMULATORS_ROOT environment variable."
+        )
 
 
 def load_python_config() -> Dict: