test: add a cli test

tests/test_cli.py

@@ -0,0 +1,30 @@
+"""Function to test the CLI"""
+
+import subprocess
+
+import xdem
+
+
+class TestCLI:
+    # Define paths to the DEM files using xDEM examples
+    ref_dem_path = xdem.examples.get_path("longyearbyen_ref_dem")
+    tba_dem_path = xdem.examples.get_path("longyearbyen_tba_dem")
+
+    def test_xdem_cli(self) -> None:
+        try:
+            # Run the xDEM CLI command with the reference and secondary DEM files
+            result = subprocess.run(
+                ["xdem", self.ref_dem_path, self.tba_dem_path],
+                capture_output=True,
+                text=True,
+            )
+            assert "hello world" in result.stdout
+            assert result.returncode == 0
+
+        except FileNotFoundError as e:
+            # In case 'xdem' is not found
+            raise AssertionError(f"CLI command 'xdem' not found : {e}")
+
+        except Exception as e:
+            # Any other errors during subprocess run
+            raise AssertionError(f"An error occurred while running the CLI: {e}")